WAFER LEVEL INTEGRATION MODULE WITH INTERCONNECTS
A wafer level integration module and method for forming are disclosed. A construction includes semiconductor functional device fabrication carried out after interconnect structures are processed on a bare wafer. Interconnect structures are formed in a first side of the wafer. An insulation layer is deposited on the first side of the wafer to insulate walls of the interconnect structures. A conductive layer is deposited on the insulation layer filling the interconnect structures so as to contact the insulation layer on the walls of the interconnect structures. The conductive layer forms interconnection contacts on the first side of the wafer and interconnection vias extending into the wafer. The first conductive layer including the interconnection contacts is exposed on the first side of the wafer and a semiconductor functional device is formed on the first side of the wafer. The semiconductor functional device is interconnected with the interconnection contacts during the fabricating. At least portions of the conductive layer associated with the interconnection vias are exposed from the second side of the wafer.
The present application is a Continuation of U.S. patent application Ser. No. 12/991,545 entitled “WAFER LEVEL INTEGRATION MODULE WITH INTERCONNECTS” filed on Nov. 8, 2010, which is a National Stage Application of International Application PCT/SG2009/000164 filed on 6 May 2009, which claims priority to Singapore Application No. 200803479-5 filed 6 May 2008 by Gautham Viswanadam.
FIELD OF THE INVENTIONThis invention relates generally to an integrated circuit (IC) device and a method of manufacturing an IC device. More particularly, this invention relates to an IC device including one or more dies arranged in an array configuration within the defined wafer geometry, and to a method of manufacturing such an IC device.
BACKGROUND OF THE INVENTIONWith the miniaturization of electronic products, there is a continuous need to reduce the size of devices and to add more functionality so that more IC devices can be accommodated area on a substrate. In prior IC device fabrication, an IC device has a foot print approximately the size of a die of the IC device. Multiple dies with multiple interconnection pads on each die are processed together to form a semiconductor wafer first. The devices that have been arrayed on the wafer are then packaged in many ways. Two such conventional packaging methods include separating the dies from the arrayed wafer prior to packaging, and packaging the arrayed dies on the semiconductor wafer while the arrayed dies are still in wafer form. After packaging, the arrayed dies are then separated, and the IC devices under conventional packaging methods are typically used in the desired application as a wafer level package device.
Referring to
For example, U.S. Pat. No. 6,040,235 and U.S. Pat. No. 6,117,707 disclose two processes that are conventional. U.S. Pat. No. 6,040,235 discloses an IC device having a footprint approximately the size of a die of the IC device. The steps for manufacturing the IC device in such a conventional process includes providing a wafer that includes multiple dies wherein each die includes multiple connection pads; sandwiching the wafer between two protective layers; cutting notches through one of the protective layers along outlines of the dies to expose portions of the connection pads; forming metal contacts on the surface of the notched protective layer that are electrically connected to the exposed portions of the connection pads; and separating the dies to form individual dies. The step of cutting notches is sequential and therefore is time-consuming, and also requires an accurate fixed angular shaped cutting blade for cutting the notches. As cutting produces debris, the cutting step has to be performed outside of a clean room to prevent contamination and damage of the device. A cut wafer is then transported into the clean room for further processing, making handling of the wafer cumbersome. Additionally, the two protective layers on a resultant die also increase the cost of fabrication.
U.S. Pat. No. 6,117,707 discloses another IC device having multiple dies similar to that disclosed in U.S. Pat. No. 6,040,235. The dies are arranged in a stacked configuration. Interconnections between the dies of such an IC device are formed only after the stacks of dies are separated to form individualized IC devices. Accordingly, the process of interconnecting the dies in a device is performed on a device level and increases fabrication time.
The conventional fabricating methods disclose packaging/interconnection of the device IOs to the external system after the devices are pre-fabricated, which limits the number of IOs and functionality of device per square of silicon area. Also additional processes and packaging are required for routing of the interconnection lines across or within the chip to the IOs located peripherally around the chip to enable external interconnections. It is well known in the art of semiconductor industry that handling of devices once it is fabricated is a critical step. Risk involved in loosing wafer yields is highly dependent on the amount of handling and process stages the device wafer undergoes after the wafer reaches packaging and assembly houses.
Such conventional fabrication methods typically require additional device packaging methods after the devices are fabricated at the semiconductor wafer fabrication facilities which results in exposing the processed device to increased risk of contamination and damage. Therefore, there is a need for a method of fabricating a functional IC device that alleviates the problems associated with prior fabrication methods.
SUMMARY OF THE INVENTIONAn aspect of the invention includes a method of fabricating a wafer level integration module according to a construction whereby semiconductor functional device fabrication is carried out only after interconnect structures are processed on a bare wafer. The interconnect structures can be formed in a first side of the wafer. A first insulation layer on the first side of the wafer can be deposited so as to insulate walls of the interconnect structures. A first conductive layer can be deposited on the insulation layer so as to fill the interconnect structures. The conductive layer is deposited so as to contact the first insulation layer on the walls of the interconnect structures and to form interconnection contacts on the first side of the wafer and interconnection vias extending into the wafer. The first conductive layer can also form interconnection contacts on the first side of the wafer. A semiconductor functional device can be fabricated on the first side of the wafer so as to be interconnected with the interconnection contacts during the fabricating thereof. At least portions of the first conductive layer associated with the interconnection vias can be exposed from the second side of the wafer.
In an embodiment the conductive layer can be a high temperature conductive film. The conductive interconnect film may be exposed by chemical mechanical polishing. A substrate may be provided and attached to the first side of conductive interconnect film to protect the first side of the wafer. A conductive material may be deposited to the second layer conductive layer for contact with external devices.
In an embodiment the semiconductor functional device may comprise depositing additional layers forming the functional device. The additional layers may form a plurality of functional devices. The additional layers may be formed in a stack formation. The plurality of dies may be formed on the wafer. The dies may be separated along separation zones the plurality of dies. The functional device may be a transistor and the plurality of functional devices may be transistors.
In an embodiment the functionality of the semiconductor device may be tested after fabrication of the device tested. The testing of the semiconductor device comprises forming test pads on the first side of the wafer. The test pads may be removed after testing and before fabrication of a subsequent device. A fourth insulation layer may be deposited to protect the second conductive layer.
In order that embodiments of the invention may be fully and more clearly understood by way of non-limitative example from the following description taken in conjunction with the accompanying drawings in which like reference numerals designate similar or corresponding elements, regions and portions, and in which:
According to an embodiment of the present invention, there is provided a method 200 of manufacturing an integrated circuit (IC) device 90. According to the method, a wafer 10 is first provided having a first or top surface and a second or bottom surface. The wafer may be a blank polished or unpolished silicon wafer or the like. High aspect ratio micro-structures 16 that are specifically designed to provide a die level interconnect configuration and mapping, are provided on the first blank surface 12 of the wafer. The wafer with pre-formed conductive interconnect microstructures 16 are further processed for device fabrication, for example, at the wafer fabrication facilities. Once the front side 12 devices are fabricated, the silicon material 20 is then removed from a second side 14 of the device wafer 10, opposite the first side, to expose the high temperature conductive interconnect microstructures 16. Contacts are formed on the second side of the device wafer using conductive metal. These contacts are electrically connected to the interior of the microstructures and thereby electrically connect with the functional device 26. The dies 90(1),90(2) are separated along the separation zones 88 between the dies to produce individualized functional and packaged dies, each of which serves as a fully packaged IC device 90. Embodiments of the invention calls for a predetermined I/O pad distribution on the raw silicon wafer prior to the device fabrication process is started. A high temperature conductive interconnect film is deposited on a raw silicon wafer with necessary dielectric insulation components to prevent electrical current leakage and circuit shorting to silicon substrate in use. Once the interconnections are made, the device under application is fabricated and the wafer further processed for interconnecting the same to the external printed circuit board. where the packaging interconnections are pre-formed on the blank wafer first prior to packaging.
A method and apparatus for manufacturing an integrated circuit (IC) device 90 is disclosed. A wafer 10 is first provided having a first or top surface and a second or bottom surface. The wafer may be a blank polished or unpolished silicon wafer or the like. High aspect ratio micro-structures 16 that are specifically designed to provide a die level interconnect configuration and mapping, are provided on the first blank surface 12 of the wafer. The wafer with pre-formed conductive interconnect microstructures 16 are further processed for device fabrication, for example, at the wafer fabrication facilities. Once the front side 12 devices are fabricated, the silicon material 20 is then removed from a second side 14 of the device wafer 10, opposite the first side, to expose the high temperature conductive interconnect microstructures 16. Contacts are formed on the second side of the device wafer using conductive metal. These contacts are electrically connected to the interior of the microstructures and thereby electrically connect with the functional device 26. The dies 90(1),90(2) are separated along the separation zones 88 between the dies to produce individualized functional and packaged dies, each of which serves as a fully packaged IC device 90.
With reference to
In
Embodiments of the invention may be configured in a silicon on insulation (SOI) structure after the microstructures are fabricated, as shown in
A method 200 of the invention in accordance with an embodiment is shown in the flow chart of
Embodiments of the invention, the interconnect microstructures are formed first on the blank silicon wafer, and then the device is fabricated over the preformed interconnect microstructures.
With this configuration, the device design may be optimized with minimal routing and ease of design while minimizing noise, maximizing device speed, and maximizing I/O pad flexibility. Additionally, the device configuration allows more functionality for reduced silicon area which results in minimized silicon cost since no peripheral bond pads are required. This allows for minimizing size of devices and silicon costs as the scribe line geometry is minimized. The functional space for the devices or more chips per wafer are maximized which also minimizes cost. As no bond pads are exposed, there are no atmospheric corrosion issues, which increase device reliability. Additionally, as no three-dimensional channels at the backside of the device are required, no thin film stress related to the three dimensional films is introduced.
Embodiments of the invention may be adapted to any device of interest and no limitations are envisaged. The thickness of the devices may be minimized, for example in the order of 10 to 50 micron with minimal interconnect channels resulting in maximized device speed, and minimized overall form factors. This approach allows fabrication of build up layers using multi layer metal, passivation layers at the back side of the device within the wafer fabrication facilities, which minimizes risk of wafer damage or contamination. This results in increased wafer yields as no handling or assembly processes are carried out on the processed wafers. Embodiments of the invention allows pre-fabrication of standard gate I/O microstructures on the wafers prior to the device fabrication, allowing a flexibility to design and use only the required I/O microstructures for designs such as gate array metal interconnects that are popular in ASIC device fabrication. Multiple devices using same or different functions can be processed on top of each previously fabricated device wafer in stack format using an epitaxial silicon intermediate film, if required. Required I/Os may also be processed as an integral part of the device fabrication that may facilitate the multiple stack die interconnections to the second side of the active device wafer.
Embodiments of the present invention virtually eliminates the packaging and assembly activities for the devices as the interconnections are carried out prior to the device fabrication during the wafer fabrication process at the wafer fabs. Embodiments of the invention offer advantages such as elimination of the requirement of bond pads at the peripheral of the devices. This gives rise to reduced silicon area and more functionality on a given silicon size, thus reducing the silicon cost. Another advantage is that circuitry for interconnection of the IOs with in the chip is minimized, which improves speed of the device and contributes to minimizing in interconnect routing noise. This contributes to the overall improvement on performance of the devices. Additionally, since no packaging such as die bonding, wire bonding, and the like is required, the cost on packaging is completely eliminated. As the I/O are predetermined before the devices are fabricated, there is no limitation on the I/O pitch with in the chip and hence high density interconnect chips can be fabricated using this process. An embodiment of the invention allows all the primary interconnections and test pads to be located within the chip without running any interconnect lines to device peripherals. Since no peripheral bond pads are involved in embodiments of invention, the scribe lines can be minimized, such as for example down to as small as 20 to 30 micron, which will allow additional silicon for additional device accommodation, thus further reducing the cost of silicon per device. The resulting reduction in street between the devices fits well into the existing laser dicing processes with optimal silicon scribe areas.
While embodiments of the invention have been described and illustrated, it will be understood by those skilled in the technology concerned that many variations or modifications in details of design or construction may be made without departing from the present invention.
Claims
1. A method of fabricating a wafer level integration module according to a construction whereby semiconductor functional device fabrication is carried out only after interconnect structures are processed on a bare wafer comprising:
- forming the interconnect structures in a first side of the wafer;
- depositing a first insulation layer on the first side of the wafer so as to insulate walls of the interconnect structures;
- depositing a first conductive layer on the insulation layer, the first conductive layer filling the interconnect structures so as to contact the first insulation layer on the walls of the interconnect structures, the first conductive layer forming interconnection contacts on the first side of the wafer and interconnection vias extending into the wafer;
- exposing the first conductive layer to form interconnection contacts on the first side of the wafer;
- fabricating a semiconductor functional device on the first side of the wafer, the semiconductor functional device interconnected with the interconnection contacts during the fabricating the semiconductor functional device; and
- exposing from the second side of the wafer, at least portions of the first conductive layer associated with the interconnection vias.
2. The method of claim 1, wherein the structures include microstructures.
3. The method of claim 1, wherein the conductive layer is a high temperature conductive film.
4. The method of claim 1, wherein the exposing the first conductive layer, including the high temperature conductive film includes exposing by chemical mechanical polishing.
5. The method of claim 1, wherein the exposing the first conductive layer, including the high temperature conductive film includes exposing by back grinding.
6. The method of claim 1, further comprising providing a protection substrate to cover the first side of the wafer so as to protect the semiconductor functional device.
7. The method of claim 1, further comprising depositing a second insulation layer on the second side of the wafer; patterning the second insulation layer and exposing the interconnection vias; depositing a second conductive layer on the patterned second insulation layer for contact with external devices.
8. The method of claim 1, wherein the fabricating the semiconductor functional devices comprises depositing additional layers for forming a new functional device.
9. The method of claim 8 wherein the additional layers form a plurality of the new functional devices.
10. The method of claim 8 wherein the additional layers are formed in a stack formation.
11. The method of claim 1, wherein the interconnect via structures, the semiconductor functional device, the first conductive layer filling the interconnect structures, interconnection contacts and interconnection vias are formed as one of a plurality of dies formed on the wafer.
12. The method of claim 11 further comprising separating the plurality of dies along separation zones.
13. The method of claim 8, wherein the semiconductor functional device includes a transistor.
14. The method of claims 9 wherein the plurality of semiconductor functional devices include transistors.
15. The method of claim 1, further comprising testing the semiconductor functional device after fabrication.
16. The method of claim 15 wherein testing the semiconductor functional device comprises forming test pads on the first side of the wafer.
17. The method of claim 15 further comprising removing the test pads after testing and before fabrication of a subsequent semiconductor functional device.
18. The method of claim 1, further comprising depositing a third insulation layer to the first conductive layer when the first conductive layer is applied to the interconnect structures in a manner so as to partially fill the interconnect structures to control a resistance of the resulting interconnection vias to planarize and protect the first conductive layer on the first side of the wafer.
19. A wafer level integration module comprising:
- interconnect structures formed on a first side of the wafer, the interconnect structures having walls including a first insulation layer applied thereon from the first side of the wafer;
- a first conductive layer applied on the insulation layer on the walls of the interconnect structures, the first conductive layer filling the interconnect structures and forming interconnection contacts on the first side of the wafer and interconnection vias extending into the wafer to a given depth;
- interconnection contacts on the first side of the wafer, the interconnection contacts including exposed portions of the first conductive layer;
- a semiconductor functional device fabricated on the first side of the wafer, the semiconductor functional device interconnected with the interconnection contacts during the fabricating the semiconductor functional device after the interconnect structures are formed; and
- interconnect via contacts on the second side of the wafer, the interconnect via contacts formed from exposed portions of the first conductive layer associated with the interconnection vias.
20. The wafer level integration module of claim 19, wherein the exposed portions on the second side of the wafer include chemical mechanical polished exposed portions.
21. The wafer level integration module of claim 19, wherein the exposed portions on the second side of the wafer include back grinded exposed portions.
22. The wafer level integration module of claim 19, further comprising a protection substrate on the first side of the wafer that covers the semiconductor functional device.
23. The wafer level integration module of claim 19, further comprising:
- a second insulation layer on the second side of the wafer; the second insulation layer having an interconnection pattern that exposes at least some of the interconnection vias; and
- depositing a second conductive layer on the patterned second insulation layer for contact with external devices.
24. The wafer level integration module of claim 19, further comprising additional layers constituting a new functional device.
25. The wafer level integration module of claim 19, further comprising test pads on the first side of the wafer, the test pads connected to the functional semiconductor device.
26. wafer level integration module of claim 19, further comprising a resistivity controlling layer applied to the first conductive layer on the first side of the wafer, the resistivity controlling layer controlling a resistivity of the interconnection structures.
Type: Application
Filed: Jul 12, 2011
Publication Date: Nov 17, 2011
Inventor: Gautham Viswanadam (Singapore)
Application Number: 13/180,605
International Classification: H01L 21/66 (20060101); H01L 23/58 (20060101);