Container, a packaging body, manufacturing method of a container, manufacturing method of a packaging body, and a compound semiconductor substrate

Info

Publication number: 20070023321
Type: Application
Filed: Oct 3, 2006
Publication Date: Feb 1, 2007
Applicant:
Inventors: Noboru Gotou (Itami-shi), Takayuki Nishiura (Itami-shi), Osamu Ohama (Osaka)
Application Number: 11/541,653

Abstract

The invention relates to a container used to store a compound semiconductor substrate where the content of tin in the container is 1 ppm or less. Further, it relates to a container used to store a compound semiconductor substrate where the content of silicon in the container is 1 ppm or less. Further, it relates to a packaging body used to store a compound semiconductor substrate, where the content of tin in the packaging body is 1 ppm or less. Further, it relates to a manufacturing method of the container and the packaging body and a compound semiconductor substrate stored in the container and the packaging body.

Description

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a container, a packaging body, manufacturing method of a container, manufacturing method of a packaging body, and a compound semiconductor substrate.

2. Description of the Background Art

Conventionally, a container made of polypropylene has been mainly used as a container for storage and conveyance of a compound semiconductor substrate. The reasons why the container made of polypropylene has been used as the container for a compound semiconductor substrate include: i) it is inexpensive; ii) it generates fewer dust particles because it has a higher strength compared with a container made of polyethylene, which is also inexpensive; iii) the amount of the impurities contained in the resin is relatively few; iv) because it is softer than a hard container such as a container made of polycarbonate and a container made of PEEK (Poly-Ether-Ether-Ketone), damage to the compound semiconductor substrate by an external impact at transport and the occurrence of scratches on the compound semiconductor substrate can be effectively prevented; and the like.

The container made of polypropylene can be manufactured, for example, by stamping and molding a graft polymer obtained by a graft reaction of polypropylene, which was obtained by polymerizing a propylene gas under the existence of an alkylaluminum such as triethylaluminium and a titanium-based catalyst such as titanium trichloride, and a silane compound (an organic compound including silicon), and then, by cross-linking the graft polymer by contacting with water under the existence of a silanol condensed catalyst (an organic compound including tin) such as dibutyltindilaurate (DBTDL) and tributyltindilaurate (TBTDL) (for example, refer to Japanese Patent Laying-Open No. 59-115351 or Japanese Patent Laying-Open No. 2-166106).

Further, the compound semiconductor substrate stored in a container is normally stored and conveyed in a condition of being stored in a packaging body. Examples of the packaging body used include materials in which an external nylon film restrains transmission of moisture and oxygen and has an appropriate strength, and an inner polyethylene film to seal the heat that is stacked in two-layers (for example, refer to Japanese Patent Laying-Open No. 2002-274594 or Japanese Patent Laying-Open No. 2003-175906). In other words, by heat-sealing a packaging body after packing a container in which a compound semiconductor substrate is stored, the compound semiconductor substrate stored in a container is stored in a packaging body in a sealed state.

In the packaging body, the nylon film and the polyethylene film are adhered with a polyester-based adhesive, and an organic compound including tin, zinc, or titanium is often used as the adhesive.

SUMMARY OF THE INVENTION

However, in the case of using the conventional container and packaging body, an abnormality of electric characteristics could occur from an outer peripheral part of the semiconductor device in which a high resistance semiconductor layer was epitaxially grown on the surface of the compound semiconductor substrate after storage. It is known that an abnormality of electric characteristics occurs due to a change over time of the compound semiconductor substrate, and it more likely occurs especially in a semiconductor device using a compound semiconductor substrate that is stored for a long period of time.

In view of the above-described considerations, the objectives of the present invention are to provide a container and a packaging body that can restrain the deterioration of electric characteristics of a semiconductor device manufactured with a compound semiconductor substrate after storage, and manufacturing methods thereof, and further, to provide a compound semiconductor substrate stored by the container and packaging body.

The container in the present invention is used to store a compound semiconductor substrate, wherein the content of tin in the container is 1 ppm or less.

Further, the container in the present invention is used to store a compound semiconductor substrate, wherein the content of silicon in the container is 1 ppm or less.

Further, the packaging body in the present invention is used to store a compound semiconductor substrate, wherein the content of tin in the packaging body is 1 ppm or less.

Further, the packaging body in the present invention is used to store a compound semiconductor substrate, including a plurality of layers wherein the plurality of layers includes at least one layer of a layer restraining transmission of tin, and the content of tin in the whole layer located more inside than the inner most layer among layers restraining transmission of tin is 1 ppm or less.

Further, the manufacturing method of the container in the present invention is a method of manufacturing the above-described container, including the steps of selecting a resin composition and forming a container using the selected resin composition.

Further, the manufacturing method of the packaging body in the present invention is a method of manufacturing the above-described packaging body, including the steps of selecting a sheet and forming a packaging body using the selected sheet.

In addition, the compound semiconductor substrate in the present invention is stored in at least a kind of container and packaging body selected from the group comprising the above-described container and the above-described packaging body, and placed in a nitrogen environment.

Furthermore, the “content of tin” in the present invention is calculated by converting to a mass of tin as a simple substance in the case when tin is included in a form of a tin compound such as an organic tin compound in the container and/or packaging body of the present invention. Further, the “content of tin” in the present invention is calculated by a sum of the mass of tin as a simple substance and the mass of tin as a simple substance calculated by being converted from a tin compound in the case when tin is included in both forms of tin as a simple substance and a tin compound such as an organic tin compound in the container and/or packaging body of the present invention.

Further, the “content of silicon” in the present invention is calculated by converting to a mass of silicon as a simple substance in the case when silicon is included in a form of a silicon compound in the container and/or packaging body of the present invention, and a sum of the mass of silicon as a simple substance and the mass of silicon as a simple substance calculated by being converted from a silicon compound in the case when silicon is included in both forms of silicon as a simple substance and a silicon compound in the container and/or packaging body of the present invention.

Further, in the present invention, “inside” means the side where the stored compound semiconductor substrate is located when the compound semiconductor substrate is stored in the container and/or packaging body of the present invention, and “outside” means the opposite side from the side where the stored compound semiconductor substrate is located when the compound semiconductor substrate is stored in the container and/or packaging body of the present invention.

According to the present invention, a container and a packaging body that can restrain the deterioration of electric characteristics of a semiconductor device manufactured with a compound semiconductor substrate after storage, and manufacturing methods thereof, and further, a compound semiconductor substrate stored by the container and packaging body can be provided.

The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of one preferred example of the container of the present invention.

FIG. 2 is a schematic perspective view of one of other preferred examples of the container of the present invention.

FIG. 3 is a schematic perspective view of one of further preferred examples of the container of the present invention.

FIG. 4 is a figure showing one example of a measurement result of sheet resistance on the surface of a wafer having a good evaluation of the electric characteristics.

FIG. 5 is a figure showing one example of a measurement result of sheet resistance on the surface of a wafer having a poor evaluation of the electric characteristics.

FIG. 6 is the result of a TOF-SIMS measurement at a center part of the surface of a GaAs substrate which was kept for three years in a container obtained by forming a polypropylene resin composition in which the content of tin is 15 ppm.

FIG. 7 is the result of a TOF-SIMS measurement at an outer peripheral part of the surface of a GaAs substrate which was kept for three years in a container obtained by forming a polypropylene resin composition in which the content of tin is 15 ppm.

FIG. 8 is a schematic cross-sectional view of one preferred example of a configuration of the packaging body of the present invention storing a compound semiconductor substrate.

FIG. 9 is a schematic enlarged sectional view of a part of one of other preferred examples of the packaging body of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiments of the present invention are explained below. Furthermore, in the drawings of the present application, a like reference letter indicates the same part or a corresponding part.

The container in the present invention is used to store a compound semiconductor substrate, characterized in that the content of tin in the container is 1 ppm or less. By using the container where the content of tin is controlled in such a manner, deterioration of electric characteristics of a semiconductor device manufactured with a compound semiconductor substrate which was stored and kept in the container for a long period of time, can be restrained.

For example, in the case that a container consists of a polypropylene resin composition, an organic tin compound included in the container moves among polypropylene molecular chains and bleeds into the inner surface of the container. Then, by contacting the inner surface of the container into which the organic tin compound has bled with the surface of a compound semiconductor substrate, the organic tin compound sticks onto the surface of the compound semiconductor substrate. In the case that a semiconductor device is manufactured by stacking a high resistance semiconductor layer on the surface of a compound semiconductor substrate on which the organic tin compound was stacked in such a manner under a high temperature of about 600° C., tin formed by decomposing the organic tin compound can get into the high resistance semiconductor layer. In a semiconductor device including a high resistance semiconductor layer in which tin has got into, current leaks from the high resistance semiconductor layer and the electric characteristics of the semiconductor device deteriorate.

Accordingly, as a result of the inventors' zealous investigation, by making the content of tin in a container 1 ppm or less of the mass of the container, it was found that the electric characteristics of a semiconductor device do not deteriorate even in the case of which the compound semiconductor substrate was kept in the container for a long period of time. Furthermore, for example, in the case that a container consists of a polypropylene resin composition, the organic tin compound is considered to be included in the polypropylene resin composition as an additive agent such as an antistatic agent mixed at a manufacturing step of the polypropylene resin composition and as a catalyst, etc.

The container in the present invention is preferably manufactured as follows. First, a lot in which a plurality of pellets consisting of a polypropylene resin composition were stored, is prepared. Next, after a powder made by pulverizing a part of the pellets stored in the lot with a crusher was dissolved in sulfuric acid, the content of tin in the pellets is measured by ICP (Induced Coupling Plasma) light-emitting analysis. Then, the measured content of tin in the pellets is converted to the content of tin per one container of the present invention and a lot having the converted value of 1 ppm or less is selected. Finally, by using the pellets in the selected lot and molding with a known molding method such as injection molding, the container in the present invention can be manufactured.

Further, the case that silicon becomes a problem instead of tin depending on the structure of a semiconductor device and the forming condition of a high resistance semiconductor layer formed on the surface of a compound semiconductor substrate is considered. In this case as well, with a same reason as the above-described case of tin, it can be considered that deterioration of the electric characteristics of a semiconductor device can be restrained if the content of silicon is 1 ppm or less of the mass of the container. Here, the content of silicon is calculated in the same manner as in the case of tin and a container of the present invention in which the content of silicon is 1 ppm or less is formed, for example, in the same manner as in the above-described case of tin, by converting the content of tin in the pellets to the content of tin per one container of the present invention and selecting a lot for which the converted value is 1 ppm or less.

Furthermore, polypropylene resin compositions which can be used in the present invention include polypropylene. Here, examples of polypropylene used include a single polymer of polypropylene, a copolymer of polypropylene and α-olefin having 2 to 20 carbon atoms except polypropylene and their mixture. Examples of the α-olefin include ethylene, 1-butene, 1-pentene, and 1-hexene. Further, examples of the copolymer include a secondary copolymer and a ternary copolymer of polypropylene and α-olefin.

Further, the polypropylene resin composition preferably consists of a mixture of a graft polymer obtained by a graft reaction of the above-described polypropylene mixing with at least an organic peroxide and a silane compound, and a silanol condensed catalyst including tin. This is because a container with improved characteristics such as heat resistance, strength, and stiffness can be manufactured by molding the polypropylene resin composition in which the silanol condensed catalyst is mixed and then by exposing to a water environment.

Here, examples of the organic peroxide used include 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, t-butylperoxyisopropylcarbonate, 2,2-bis(t-butylperoxy)butane, t-butylperoxybenzate, dichmilperoxide, and 2,5-dimethyl-2,5-di(t-butylperoxy)hexane. The mixing amount of the organic peroxide is preferably 0.05 to 1 part by mass to polypropylene 100 part by mass.

Further, examples of the silane compound used include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, and γ-methacryloyloxypropyltrimethoxysilane. The mixing amount of the silane compound is preferably 1 to 20 part by mass to polypropylene 100 part by mass.

Further, examples of the silanol condensed catalyst used include dibutyltindilaurate, tributhyltindilaurate, dibuthyltindiacetate, and dibuthyltindioctate.

Further, it is needless to say that additives such as a pigment, a filler, an antistatic agent, a flame retardant, and an anti-aging agent can be properly mixed in the polypropylene resin composition.

A schematic perspective view of one preferred example of the container of the present invention is shown in FIG. 1. In a container 1, by closing a lid part 1b after installing a compound semiconductor substrate 2 in a support part 1a of container 1, compound semiconductor substrate 2 is stored. Here, support part 1a is concave where the center part is caved in and compound semiconductor substrate 2 is supported by a part of the outer peripheral part of compound semiconductor substrate 2 contacting to support part 1a.

A schematic perspective view of one of other preferred examples of the container of the present invention is shown in FIG. 2. In container 1, by closing lid part 1b after installing compound semiconductor substrate 2 in support part 1a of container 1 and installing a press member 3 on compound semiconductor substrate 2, compound semiconductor substrate 2 is stored. Here, support part 1a is also concave where the center part is caved in and compound semiconductor substrate 2 is supported by all of the outer peripheral part of compound semiconductor substrate 2 contacting to support part 1a.

A schematic perspective view of one of further preferred examples of the container of the present invention is shown in FIG. 3. In container 1, a part of the outer peripheral part of compound semiconductor substrate 2 is supported by container 1 and a plurality of compound semiconductor substrates 2 are stored.

A container of the present invention preferably has a structure that does not contact with the surface of the compound semiconductor substrate if possible, in order to avoid the surface of the compound semiconductor substrate to be contaminated by an organic tin compound that has bled into the inner surface of the container. Therefore, the container of the present invention preferably uses a configuration in which the container stores generally in a condition that a part of the outer peripheral part of the compound semiconductor substrate is contacting with the container.

Furthermore, needless to say, a configuration of the container of the present invention is not restrained to the above-described configurations shown in FIG. 1 to FIG. 3.

A packaging body in the present invention is used to store a compound semiconductor, characterized in that a content of tin in a packaging body is 1 ppm or less.

A schematic cross-sectional view of one preferred example of a configuration of the packaging body of the present invention storing a compound semiconductor substrate is shown in FIG. 8. In FIG. 8, a packaging body 4 has a two-layered structure of a polyethylene film layer 5 inside and a nylon film layer 6 outside, and compound semiconductor substrate 2 stored in container 1 consisting of, for example, a polypropylene resin composition, is stored in packaging body 4. Then, the inside of packaging body 4 is kept airtight by heat-sealing the polyethylene film layers 5 together.

Here, although polyethylene film layer 5 and nylon film layer 6 constituting packaging body 4 are adhered with, for example, a polyester-based adhesive, an organic tin compound can be included in the adhesive as a curing reaction accelerator. The organic tin compound moves among polypropylene molecular chains in polyethylene film layer 5 and bleeds into the inner surface of polyethylene film layer 5. Then, by contacting the inner surface of polyethylene film layer 5 into which the organic tin compound has bled with the outer surface of container 1, the organic tin compound sticks to the outer surface of container 1. Continuing, the organic tin compound stack on the outer surface of container 1 moves among polypropylene molecular chains in container 1 and bleeds into the inner surface of container 1.

Subsequently, by contacting the inner surface of container 1 where the organic tin compound has bled with the surface of compound semiconductor substrate 2, the organic tin compound sticks to the surface of compound semiconductor substrate 2. Then, as described above, in the case that a semiconductor device is manufactured by stacking a high resistance semiconductor layer on the surface of compound semiconductor substrate 2 where the organic tin compound was stuck, under a high temperature of about 600° C., tin formed by decomposing the organic tin compound can get into the high resistance semiconductor layer, and it is considered that the current leaks from the high resistance semiconductor layer, and the electric characteristics of the semiconductor device deteriorate.

Therefore, for example, even in the case of storing the compound semiconductor substrate in the container in which the content of tin is 1 ppm or less, when the content of tin in the packaging body which packs the container is more than 1 ppm, deterioration of the electric characteristics of the semiconductor device manufactured with the compound semiconductor substrate stored in this container and packaging body for a long period of time cannot be restrained sufficiently. Accordingly, by making a content of the tin in the packaging body 1 ppm or less, deterioration of the electric characteristics of the semiconductor device can be restrained more effectively.

Furthermore, in the above, the case was explained when after the organic tin compound in the inner surface of the packaging body of the present invention adheres to the outer surface of the container, it bleeds into the inner surface of the container, and adheres to the surface of the compound semiconductor substrate. It can be also considered that the organic tin compound on the inner surface of the packaging body of the present invention adheres directly onto the surface of the compound semiconductor substrate.

A packaging body in the present invention is preferably manufactured as follows. First, a sheet web in which a nylon film and a polyethylene film are adhered together with a polyester-based adhesive, is prepared. Next, a sheet is cut out from the sheet web, and after a powder made by pulverizing the cut-out sheet with a crusher is dissolved in sulfuric acid, the content of tin in the sheets is measured by ICP light-emitting analysis. Then, the measured content of tin in the sheet is converted to the content of tin per one packaging body of the present invention, a sheet web is selected from which a sheet having the converted value of 1 ppm or less is cut, and by using a sheet of the selected sheet web, the packaging body in the present invention is formed. The configuration of the packaging body of the present invention is not especially restrained.

Further, a schematic enlarged sectional view of a part of one of other preferred examples of the packaging body of the present invention is shown in FIG. 9. Here, packaging body 4 of the present invention is constituted with an inside layer 7 and an outside layer 8, and inside layer 7 and outside layer 8 are adhered together with an adhesive. Then, the content of tin in inside layer 7 is 1 ppm or less and outside layer 8 is a layer restraining transmission of tin. By having this constitution, not only can invasion of tin from the outside of packaging body 4 be restrained, but also deterioration of the electric characteristics of the semiconductor device manufactured with the compound semiconductor substrate after the storage can be restrained even in the case of which the compound semiconductor substrate was kept for a long period of time in the condition that the inner surface of inside layer 7 contacts with the surface of the compound semiconductor substrate and/or the outer surface of the container storing the compound semiconductor substrate because the content of tin in inside layer 7 is 1 ppm or less.

Here, examples of outside layer 8 that restrain transmission of tin include a nylon film and poly(ethyleneterephthalate) film. Further, examples of inside layer 7 used include a polyethylene film which is a material that can be heat-sealed together from a point of view to seal up and store the compound semiconductor substrate.

Further, outside layer 8 may consist of not only a single layer but also a plurality of layers and it is better if at least one of the layers is a layer that restrains transmission of tin (hereinafter termed the tin transmission restraining layer) in the case that outside layer 8 consists of a plurality of layers. Then, in this case, considering inside layer 7 to be all layers which are inside of the tin transmission restraining layer that is the most inside, it is better if the content of tin in inside layer 7 is 1 ppm or less. Furthermore, inside layer 7 may also consist of not only a single layer but also a plurality of layers.

The compound semiconductor substrate stored by the container and/or the packaging body of the present invention is preferably placed in a nitrogen environment. In this case, not only invasion and adhesion of foreign substances such as tin and silicon on the surface of the compound semiconductor substrate can be restrained, but also there is a tendency that the transitional change of the compound semiconductor substrate can be restrained. Therefore, without cleaning the compound semiconductor substrate of the present invention, a semiconductor layer can be epitaxially grown on the surface of the compound semiconductor substrate of the present invention. Furthermore, in the present invention, the inside of the container and/or the packaging body may be in a nitrogen environment and the compound semiconductor substrate may be placed in a nitrogen environment.

Examples of the compound semiconductor substrate in the present invention include a GaAs (gallium arsenide) substrate, an InP (indium phosphide) substrate, a GaN (gallium nitride) substrate, and an AlN (aluminum nitride) substrate.

EXAMPLE 1

After dichmilperoxide 0.5 part by mass and γ-methacryoxypropyltrimethoxysilane 10 part by mass were mixed in polypropylene 100 part by mass in powder form, the mixture was provided to an extruder, and a graft reaction was performed while stirring the mixture at a temperature of 180° C.

Subsequently, by providing a graft polymer obtained from the graft reaction and molded in a pellet form, and a master patch in which dibuthyltindilaurate was mixed by changing the mixing amount into the above-described polypropylene 100 part by mass to an extruder at the ratio of 9:1 and mixing, lots were obtained in which a plurality of each pellet consisting of five kinds of polypropylene resin compositions with different contents of tin were contained.

Then, after a part of these pellets were picked from these five kinds of lots, these pellets were pulverized with a crusher, and after the powder was dissolved with sulfuric acid, the content of tin in the pellet of each lot was measured with ICP light-emitting analysis. After this, by injection-molding using a pellet contained in each of five kinds of lots, five kinds of molding having a form of container 1 shown in FIG. 2 were obtained. Then, these moldings were soaked in water at 100° C. for 3 hours and the containers of sample No. 1 to 5 were manufactured.

A GaAs substrate of 4 inches diameter was contained in each container of sample No. 1 to 5 without using press member 3 shown in FIG. 2, and stored for three months under the same condition. Here, all of the outer peripheral part of the GaAs substrate was in contact with the surface of the container. Then, a high resistance GaAs layer of 500 nm thickness was layered on the surface of each GaAs substrate with an MBE method (Molecular Beam Epitaxy method) in a condition where the surface temperature of the GaAs substrate was 600° C. Subsequently, by layering a Si doped n-type AlGaAs layer of 50 nm thickness with an MBE method, a wafer having a HEMT (High Electron Mobility Transistor) structure was formed.

Then, the sheet resistance was measured for each of these wafers and evaluation of the electric characteristics was performed based on the evaluation criteria described below. The result is shown in Table 1. As shown in Table 1, for a wafer using a GaAs substrate stored in the container of sample No. 1 in which the content of tin was 1 ppm, variation of the sheet resistance on the wafer surface was 2% or less. Further, for a wafer using a GaAs substrate stored in the containers of samples No. 2 to 5 in which the content of tin was more than 1 ppm, it is confirmed that variation of sheet resistance on the wafer surface was 20% to 30%.

It is considered that because the high resistance GaAs layer was layered under the high temperature of 600° C. in the condition where an organic tin compound was adhered on the surface of the GaAs substrate, tin formed by decomposing the organic tin compound got into the high resistance GaAs layer and the sheet resistance on the wafer surface decreased. Furthermore, the content of tin shown in Table 1 is the value for which the content of tin in the pellet measured with the above-described ICP light-emitting analysis was converted to the content of tin per one container.

Here, because the containers of sample No. 1 to 5 were not molded in the condition where tin gets into, the content of tin shown in Table 1 is considered to be same as the content of tin in the containers of sample No. 1 to 5 after being molded. Further, the evaluation of the electric characteristics using the containers of sample No. 1 to 5 having a form shown in FIG. 2 is considered to be applicable to the containers with all other forms because it is the most severe case in which all of the outer peripheral part of the surface of the GaAs substrate is in contact with the surface of the container and stored.

TABLE 1 Sample No. Content of tin (ppm) Electric Characteristics 1 1 GOOD 2 12 POOR 3 15 POOR 4 14 POOR 5 14 POOR

Good : Variation of the sheet resistance on the wafer surface is 2% or less.

Poor: Variation of the sheet resistance on the wafer surface is more than 2%.

Furthermore, the variation of the sheet resistance of the wafer surface was calculated by dividing the standard deviation of the sheet resistance on the wafer surface by the mean value of the sheet resistance on the wafer surface.

Further, one example of a measurement result of the sheet resistance on the wafer surface in which the above-described evaluation of the electric characteristics is good is shown in FIG. 4, and one example of a measurement result of the sheet resistance on the wafer surface in which the evaluation of the electric characteristics is poor is shown in FIG. 5. Here, variation of the sheet resistance of the wafer surface shown in FIG. 4 is 1.55%, and variation of the sheet resistance of the wafer surface shown in FIG. 5 is 21.61%. Further, when the measurement results of the sheet resistance on the wafer surface shown in FIG. 4 and FIG. 5 are compared, it is confirmed that there are a large number of points where the sheet resistance is low in the outer peripheral part of the wafer shown in FIG. 5. Therefore, the organic tin compound adhered on the outer peripheral part of the surface of the GaAs substrate which has been contacted with the container is considered to get into the high resistance GaAs layer layered on the surface of the GaAs substrate from the points.

Further, a GaAs substrate was stored and kept for three years in the container of a form shown in FIG. 2, which was obtained by molding a polypropylene resin composition in which the content of tin is 15 ppm by using the same manufacturing method as one of the above-described container of sample No. 3. Then, the impurities sticking on the surface of the GaAs substrate after storage were analyzed with TXRF (Total Reflection X-Ray Fluorescence). The result is shown in Table 2. As shown in Table 2, although tin was not detected in the center part of the surface of the GaAs substrate, tin was detected in the outer peripheral part.

TABLE 2 Center part of the surface Outer peripheral part of the Detected of the GaAs substrate surface of the GaAs substrate Element (×10¹⁰/cm²) (×10¹⁰/cm²) K 3 0 Ca 11 14 Ti 0 0 Sn 0 32

Further, a measurement result of TOF-SIMS (Time Of Fright Secondary Ion Mass Spectroscopy) in the center part of the surface of the GaAs substrate is shown in FIG. 6, and a measurement result of TOF-SIMS in the outer peripheral part of the surface of the GaAs substrate is shown in FIG. 7. When the measurement results of TOF-SIMS shown in FIG. 6 and FIG. 7 are compared, fragments of tin (Sn) and buthyltin (C₄H₉Sn) were confirmed in the outer peripheral part of the surface of the GaAs substrate as shown in FIG. 7.

EXAMPLE 2

Seven kinds of a sheet web, in which a nylon film of 25 μm thickness and a polyethylene film of 30 μm thickness were adhered together with seven kinds of a polyester-based adhesive with different contents of organic tin compound, were manufactured respectively. Then, by cutting out a sheet from these seven kinds of a sheet web respectively, dissolving in sulfuric acid a powder made by pulverizing the. cut-out sheet with a crusher, and performing ICP light-emitting analysis, the content of tin in these sheets was measured respectively.

Subsequently, a sheet was cut out from each of these seven kinds of a sheet web and the packaging body of sample No. 6 to 12 were manufactured. Then, a GaAs substrate of 4 inches diameter was stored in container 1 of a form shown in FIG. 2 in which the content of tin was 1 ppm without using press member 3 shown FIG. 2 in a nitrogen environment. Then, by packing respectively with packaging body 2 of samples No. 6 to 12 in the manner that all of the inner surface of the packaging body of sample No. 6 to 12 adhere tightly to the outer surface of the container and heat-sealing the peripheral edge part of each of these packaging bodies, the GaAs substrate was sealed hermetically.

Then, the packaging body of samples No. 6 to 12 in which the GaAs substrate was sealed were kept in this condition for one year. Then, a high resistance GaAs layer of 500 nm thickness was layered on the surface of each GaAs substrate after storage with an MBE method in a condition where the surface temperature of the GaAs substrate was 600° C. Continuing, by layering a Si doped n-type AlGaAs layer of 50 nm thickness with an MBE method, a wafer having a HEMT structure was formed.

Then, from the photoluminescence light-emitting intensity in the peripheral edge part of the wafer surface and the photoluminescence light-emitting intensity of the entire surface of the wafer, occurring by irradiating the entire surface of each wafer with light, the electric characteristics of the wafer were evaluated with the evaluation criteria described below. The result is shown in Table 3. Furthermore, the photoluminescence light-emitting intensity in the peripheral edge part of the above-described wafer surface is a mean value of the photoluminescence light-emitting intensity of any four points in the peripheral edge of the wafer surface.

TABLE 3 Sample No. Content of Tin (ppm) Evaluation 6 0.4 GOOD 7 0.6 GOOD 8 0.9 GOOD 9 1.0 GOOD 10 1.2 POOR 11 1.4 POOR 12 1.9 POOR

Poor: The photoluminescence light-emitting intensity in the peripheral edge part of the wafer surface is less than two times of the mean value of the photoluminescence light-emitting intensity of the entire surface of the wafer.

Good: Those other than the above-described poor evaluation.

As shown in Table 3, for a wafer manufactured using the GaAs substrate which was stored and kept in a nitrogen environment for one year in the packaging body of sample No. 10 to 12 in which the content of tin is more than 1 ppm, the photoluminescence light-emitting intensity in the peripheral edge part of the wafer surface was less than two times of the mean value of the photoluminescence light-emitting intensity of the entire surface of the wafer. Therefore, in the case that the substrate was stored in the packaging body of sample No. 10 to 12, because the photoluminescence light-emitting intensity in the peripheral edge part of the wafer surface was very much different from a mean value of the photoluminescence light-emitting intensity in the entire surface of the wafer, an abnormality of the electric characteristics for these wafers is considered to occur.

On the other hand, for a wafer manufactured using the GaAs substrate which was stored and kept in a nitrogen environment for one year in the packaging body of samples No. 6 to 9 in which the content of tin was 1 ppm or less, compared with the cases of samples No. 10 to 12, the photoluminescence light-emitting intensity in the peripheral edge part of the wafer surface was not different than the mean value of the photoluminescence light-emitting intensity of the entire surface of the wafer. Therefore, in the case that the substrate was stored in the packaging body of samples No. 6 to 9, because even the peripheral edge part of the wafer surface is considered to have stable electric characteristics, the occurrence of abnormality of the electric characteristics is considered to be restrained.

Furthermore, the content of tin shown in Table 3 is the value for which the content of tin in the sheet measured with the above-described ICP light-emitting analysis was converted to the content of tin per one packaging body of samples No. 6 to 12. Further, because Example 2 was performed in the most severe condition in which all of the inner surface of the packaging body was brought into close contact with the outer surface of the container and stored, it is considered to be applicable to the packaging bodies with all other forms.

EXAMPLE 3

A sheet was cut out from each of these seven kinds of a sheet web with different contents of the organic tin compound used in Example 2, and the packaging body of samples No. 13 to 19 were manufactured. Then, a GaAs substrate of 2 inches diameter was stored in container 1 of a form shown in FIG. 2 in which the content of tin was 1 ppm without using the press member 3 shown FIG. 2 in a nitrogen environment. Here, the outer peripheral part of a GaN substrate was in contact with the surface of container 1.

Then, the same as Example 2, by packing respectively with the packaging body of samples No. 13 to 19 in the manner that all of the inner surface of the packaging body of samples No. 13 to 19 adhere tightly to the outer surface of the container and heat-sealing the peripheral edge part of each of these packaging bodies, the GaAs substrate was sealed hermetically.

Then, the packaging body of sample No. 13 to 19 in which the GaN substrate was sealed were kept in this condition for one year. Then, by layering an i-type GaN layer of 3 μm thickness on the surface of each GaN substrate after storage with an MOCVD method (Metal-Organic Chemical Vapor Deposition method) and layering an Al_0.25Ga_0.75N layer of 30 nm thickness on the top, a wafer having a HEMT structure was formed.

Then, from the photoluminescence light-emitting intensity in the peripheral edge part of the wafer surface and the photoluminescence light-emitting intensity of the entire surface of the wafer, occurring by irradiating the entire surface of each wafer with light, the electric characteristics of the wafer were evaluated with the same evaluation criteria as in Example 2. The result is shown in Table 4. Furthermore, the photoluminescence light-emitting intensity in the peripheral edge part of the above-described wafer surface is the mean value of the photoluminescence light-emitting intensity of any four points in the peripheral edge of the wafer surface.

TABLE 4 Sample No. Content of Tin (ppm) Evaluation 13 0.4 Good 14 0.6 Good 15 0.9 Good 16 1.0 Good 17 1.2 Poor 18 1.4 Poor 19 1.9 Poor

As shown in Table 4, for a wafer manufactured using the GaN substrate which was stored and kept in a nitrogen environment for one year in the packaging body of samples No. 17 to 19 in which the content of tin was more than 1 ppm, because the photoluminescence light-emitting intensity in the peripheral edge part of the wafer surface was very much different than the mean value of the photoluminescence light-emitting intensity of the entire surface of the wafer, an abnormality of the electric characteristics for these wafers is considered to occur.

Furthermore, the content of tin shown in Table 4 is the value of which the content of tin in the sheet measured with the above-described ICP light-emitting analysis was converted to the content of tin per one packaging body of samples No. 13 to 19. Further, because example 3 was performed in the most severe condition in which all of the inner surface of the packaging body was brought into close contact with the outer surface of the container and stored, it is considered to be applicable to the packaging bodies with all other forms.

EXAMPLE 4

A sheet was cut out from each of the seven kinds of sheet web with different contents of the organic tin compound used in Example 2, and the packaging body of samples No. 20 to 26 were manufactured. Then, a GaAs substrate of 2 inches diameter was stored in container 1 of a form shown in FIG. 2 in which the content of tin was 1 ppm without using press member 3 shown FIG. 2 in a nitrogen environment. Here, the outer peripheral part of a GaN substrate was in contact with the surface of container 1.

Then, the same as Example 2, by packing respectively with the packaging body of samples No. 20 to 26 in the manner that all of the inner surface of the packaging body of samples No. 20 to 26 adhere tightly to the outer surface of the container and heat-sealing the peripheral edge part of each of these packaging bodies, the GaAs substrate was sealed hermetically.

Then, the packaging body of samples No. 20 to 26 in which the GaN substrate was sealed were kept in this condition for one year. Then, by layering an n-type GaN layer of 5 μm thickness, an In_0.2Ga_0.8N layer of 3 nm thickness, an Al_0.2Ga_0.8N layer of 60 nm thickness, and a p-type GaN layer of 150 nm thickness successively on the surface of each GaN substrate after the storage with an MOCVD method, a wafer having a LED (Light Emitting Diode) structure was formed.

Then, from the photoluminescence light-emitting intensity in the peripheral edge part of the wafer surface and the photoluminescence light-emitting intensity of the entire surface of the wafer, occurring by irradiating the entire surface of each wafer with light, the electric characteristics of the wafer were evaluated with the same evaluation criteria as in Example 2. The result is shown in Table 5. Furthermore, the photoluminescence light-emitting intensity in the peripheral edge part of the above-described wafer is the mean value of the photoluminescence light-emitting intensity of any 4 points in the peripheral edge of the wafer surface.

TABLE 5 Sample No. Content of Tin (ppm) Evaluation 20 0.4 Good 21 0.6 Good 22 0.9 Good 23 1.0 Good 24 1.2 Poor 25 1.4 Poor 26 1.9 Poor

As shown in Table 5, for a wafer manufactured using the GaN substrate which was stored and kept in a nitrogen environment for one year in the packaging body of samples No. 20 to 26 in which the content of tin was more than 1 ppm, because the photoluminescence light-emitting intensity in the peripheral edge part of the wafer surface was very much different than the mean value of the photoluminescence light-emitting intensity of the entire surface of the wafer, an abnormality of the electric characteristics for these wafers is considered to occur.

Furthermore, the content of tin shown in Table 5 is the value of which the content of tin in the sheet measured with the above-described ICP light-emitting analysis was converted to a content of tin per one packaging body of samples No. 20 to 26. Further, because example 4 was performed in the most severe condition in which all of the inner surface of the packaging body was brought into close contact with the outer surface of the container and stored, it is considered to be applicable to the packaging bodies with all other forms.

Furthermore, although the above-described Examples 2 to 4 show a case in which an HEMT structure was formed and a case in which an LED structure was formed, the same results as in Example 2 to 4 were obtained in the case where a Schottky diode structure was formed and the case where a laser diode structure was formed.

Further, because a semiconductor device is hardly manufactured using a compound semiconductor substrate which was stored as long as one year in the current semiconductor industry, the results shown in Examples 2 to 4 are considered to have sufficient industrial meaning.

The present invention is preferably utilized for a container and a packaging body used at the time of the storage and transportation of a compound semiconductor substrate. In the case where a semiconductor device was manufactured using a compound semiconductor substrate stored for a long period of time using the container and/or the packaging body of the present invention, the occurrence of abnormality of the electric characteristics of the semiconductor device can be restrained.

Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims.

Claims

1. A container used to store a compound semiconductor substrate, where the content of tin in the container is 1 ppm or less.

2. The manufacturing method of the container as in claim 1 comprising the steps of selecting a resin composition and forming the container using the selected resin composition.

3. A container used to store a compound semiconductor substrate, where the content of silicon in the container is 1 ppm or less.

4. The manufacturing method of the container as in claim 3 comprising the steps of selecting a resin composition and forming the container using the selected resin composition.

5. A packaging body used to store a compound semiconductor substrate, where the content of tin in the packaging body is 1 ppm or less.

6. The manufacturing method of the packaging body as in claim 5 comprising the steps of selecting a sheet and forming the packaging body using the selected sheet.

7. A packaging body used to store a compound semiconductor substrate, where the packaging body comprises a plurality of layers, the plurality of layers comprises at least one layer which restrains the transmission of tin, and the content of tin in all the layers located more inside than the inner most layer of the layers which restrain the transmission of tin is 1 ppm or less.

8. The manufacturing method of the packaging body as in claim 7 comprising the steps of selecting a sheet and forming the packaging body using the selected sheet.

9. A compound semiconductor substrate stored in at least one kind selected from a group comprising the container as in claim 1, the container as in claim 3, the packaging body as in claim 5, and the packaging body as in claim 7, and placed in a nitrogen environment.