SEMICONDUCTOR COMPONENT AND METHOD OF MANUFACTURE
A semiconductor component having a semiconductor chip mounted on a packaging substrate and a method for manufacturing the semiconductor component that uses batch processing steps for fabricating the packaging substrate. A heatsink is formed using an injection molding process. The heatsink has a front surface for mating with a semiconductor chip and a leadframe assembly. The heatsink also has a back surface from which a plurality of fins extend. The leadframe assembly includes a leadframe having leadframe leads extending from opposing sides of the leadframe to a central area of the leadframe. A liquid crystal polymer is disposed in a ring-shaped pattern on the leadframe leads. The liquid-crystal polymer is partially cured. The leadframe assembly is mounted on the front surface of the heatsink and the liquid crystal polymer is further cured to form a packaging assembly, which is then singulated into packaging substrates.
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The present application is a divisional of U.S. application Ser. No. 11/958,889 filed Dec. 18, 2007, which in turn is a continuation of U.S. application Ser. No. 11/327,552 filed Jan. 6, 2006, now U.S. Pat. No. 7,335,534. Said application Ser. No. 11/958,889 and said application Ser. No. 11/327,552 are hereby incorporated herein by reference in their entireties.
TECHNICAL FIELDThe present disclosure relates, in general, to a semiconductor component and, more particularly, to a semiconductor component package.
BACKGROUNDSemiconductor component manufacturers are constantly striving to increase the performance of their products, while decreasing their cost of manufacture. A cost intensive area in the manufacture of semiconductor components is packaging the semiconductor chips that contain the semiconductor devices. As those skilled in the art are aware, discrete semiconductor devices and integrated circuits are fabricated in wafers, which are then singulated or diced to produce semiconductor chips. One or more semiconductor chips are placed in a package to protect them from environmental and physical stresses.
Packaging semiconductor chips increases the cost and complexity of manufacturing semiconductor components because the packaging designs must not only provide protection, they must also permit transmission of electrical signals to and from the semiconductor chips and removal of heat generated by the semiconductor chip.
Claimed subject matter is particularly pointed out and distinctly claimed in the concluding portion of the specification. However, such subject matter may be understood by reference to the following detailed description when read with the accompanying drawings in which:
It will be appreciated that for simplicity and/or clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, if considered appropriate, reference numerals have been repeated among the figures to indicate corresponding and/or analogous elements.
DETAILED DESCRIPTIONIn the following detailed description, numerous specific details are set forth to provide a thorough understanding of claimed subject matter. However, it will be understood by those skilled in the art that claimed subject matter may be practiced without these specific details. In other instances, well-known methods, procedures, components and/or circuits have not been described in detail.
In the following description and/or claims, the terms coupled and/or connected, along with their derivatives, may be used. In particular embodiments, connected may be used to indicate that two or more elements are in direct physical and/or electrical contact with each other. Coupled may mean that two or more elements are in direct physical and/or electrical contact. However, coupled may also mean that two or more elements may not be in direct contact with each other, but yet may still cooperate and/or interact with each other. For example, “coupled” may mean that two or more elements do not contact each other but are indirectly joined together via another element or intermediate elements. Finally, the terms “on,” “overlying,” and “over” may be used in the following description and claims. “On,” “overlying,” and “over” may be used to indicate that two or more elements are in direct physical contact with each other. However, “over” may also mean that two or more elements are not in direct contact with each other. For example, “over” may mean that one element is above another element but not contact each other and may have another element or elements in between the two elements. Furthermore, the term “and/or” may mean “and”, it may mean “or”, it may mean “exclusive-or”, it may mean “one”, it may mean “some, but not all”, it may mean “neither”, and/or it may mean “both”, although the scope of claimed subject matter is not limited in this respect. In the following description and/or claims, the terms “comprise” and “include,” along with their derivatives, may be used and are intended as synonyms for each other.
In accordance with one embodiment, after dispensing the liquid crystal material on the leadframe leads, it is partially cured (reference number 18) by exposing it to heat at a temperature ranging from about 260° C. to about 280° C. for a time period ranging from about 20 minutes to about 60 minutes under low pressure. A low pressure is a pressure of less than 1,000 pounds per square inch (psi), or less than 6895 kiloPascals (kPa). By way of example, the liquid crystal polymer is partially cured at a pressure of about 100 psi (i.e., about 689 kPa). The partial curing step sufficiently solidifies the liquid crystal material so that it maintains its form while making the liquid crystal polymer tacky or sticky.
The liquid crystal material is positioned on or mated with the heatsinks (reference number 20). Because the partial curing step makes the liquid crystal polymer tacky, it sticks to the heatsink, thereby coupling the leadframe leads to the heatsink. Preferably, mating the liquid crystal material with the heatsinks occurs while the heatsinks are still positioned in the molds in which they were cast.
The leadframe leads and heatsinks are pressed together by applying pressure to one or both of them and the liquid crystal material is fully cured (reference number 22) by exposing it to heat at a temperature ranging from about 280° C. to about 300° C. for a time period ranging from about 20 minutes to about 60 minutes under low pressure, e.g., about 100 psi (i.e., about 689 kPa). After fully curing the liquid crystal polymer, the plurality of heatsinks, leadframe leads, and liquid crystal polymer form a unitary packaging structure comprising a plurality of packaging substrates. The unitary packaging structure is singulated into individual packaging substrates using, for example, sawing or laser cutting (reference number 24).
After forming heatsinks 88, the top portion of the mold assembly is removed and a heatsink 88 having a platform 89 remains in each of cavities 52A-52D, 54A-54D, 56A-56D, and 58A-58D. It should be noted that platform 89 is an optional feature of heatsink 88 and is formed by including a cavity in the top portion (not shown) of the mold assembly.
Referring now to
A liquid crystal polymer is dispensed in annular or ring-shaped patterns to form a plurality of ring-shaped dielectric structures 132 over portions of a bottom side of leadframe 100. Ring-shaped dielectric structures 132 are thermally conductive, but electrically non-conductive. More particularly, each ring-shaped dielectric structure is a quadrilateral structure having opposing walls 134 and 136 and opposing walls 138 and 140. The portion of the liquid crystal polymer forming wall 134 is disposed on a central portion of leadframe lead 128, i.e., the liquid crystal polymer is spaced apart from an end 129 of leadframe lead 128. The portion of the liquid crystal polymer forming wall 136 is disposed adjacent an end 131 of leadframe lead 130. Preferably, end 131 of leadframe lead 130 is aligned with an edge of wall 136. However, the positioning of wall 136 on leadframe leads 128 and 130 are not limitations of the claimed subject matter. The liquid crystal polymer is partially cured by exposing it to heat at a temperature ranging from about 260° C. to about 280° C. for a time period 10 ranging from about 20 minutes to about 60 minutes under low pressure, e.g., 100 psi (i.e., about 689 kPa). As described with reference to
Referring now to
Referring now to
Semiconductor chip 152 has opposing surfaces 154 and 156 and is joined with platform 89 of singulated packaging substrate 142. In accordance with one embodiment, semiconductor chip 152 is a Radio Frequency (RF) power transistor in which a gate structure 158 is formed on a peripheral portion 160 of semiconductor chip 152 and a source region 162 is formed from a central portion of semiconductor chip 152. Gate structure 158 comprises a gate dielectric disposed on surface 154 and a gate conductor disposed on the gate dielectric. A contact 168 is formed on source region 162. Suitable metallization systems for contact 168 include a titanium-nickel-gold alloy or a titanium-nickel silver alloy. Contact 168 is soldered to platform 89. An end 172 of a microstrip line 170 is soldered to gate structure 158 and an opposing end 174 of microstrip line 170 is soldered to leadframe lead 128. Suitable materials for microstrip line 170 include gold plating on a ceramic substrate, gold plating over metal on a liquid crystal polymer substrate, or the like. Although gate structure 158 is described as being coupled to leadframe lead 128 by bonding a microstrip line 170 to its bottom surface, this is not a limitation of the claimed subject matter. For example, gate structure 158 can be coupled either to the top or bottom of leadframe lead 128 by an electrically conductive clip or the like. Preferably, the means for coupling gate structure 158 to leadframe lead 128 matches the impedance at gate structure 158 to reduce reflections of the electrical signal.
A central portion of surface 156 serves as a drain 164 of RF power transistor 152. Optionally, the central portion of semiconductor chip 152 is thinned from surface 156 into semiconductor chip 152 during wafer processing, thereby forming a lip 166 along the periphery of surface 156. Thinning the central portion of semiconductor chip 152 improves the transfer of heat away from semiconductor chip 152, but makes it more fragile. Forming lip 166 from back surface 156 increases the structural integrity of semiconductor chip 152. A contact 176 is formed on drain region 164. Suitable metallization systems for contact 176 include an aluminum layer having a nickel-gold alloy disposed thereon or an aluminum layer having a nickel-silver alloy disposed thereon.
An end 182 of a clip 180 is soldered to drain contact 176 and an end 184 of clip 180 is soldered to leadframe lead 130. By way of example, clip 180 comprises a copper-tungsten alloy. The means for coupling leadframe lead 130 to drain contact 176 is not limited to being a clip. For example, the coupling means includes a solder connection, wirebonding techniques, lead bonding techniques, or the like.
Briefly referring to
Referring now to
A leadframe having leads on which liquid crystal polymer is dispensed in an annular or ring-shaped pattern is provided. The leadframe on which the liquid crystal polymer is dispensed is similar to leadframe 100 described with reference to
Referring again to
In accordance with one embodiment, the plurality of semiconductor chips mounted to heatsink 254 include an RF power transistor 280, a switching device 282, and a mixed signal integrated circuit 284. The backside or non-active side of each chip may be electrically coupled to heatsink 254 or the backsides of semiconductor chips 280, 282, and 284 may be coupled to heatsink 254 through an insulating material such as, for example, liquid crystal polymer. Leadframe leads 256-275 are coupled to portions of semiconductor chips 280, 282, and 284 using, for example, wirebonds or clips. It should be understood that the choice of which leadframe leads 256-275 to couple to a semiconductor chip and to which bond pads (not shown) on the semiconductor chip is a design choice. It should be further understood that the chips may be coupled to each other by, for example, wirebonding. For the sake of clarity, the wirebonds have not been shown in
Optionally, a lid such as, for example, lid 202, can be mounted on packaging substrate 250. Referring now to
Semiconductor chip 302 is coupled to a ball grid array substrate 306 via a liquid crystal polymer 322. Ball grid array substrate 306 has a top surface 330 having landing pads 332 and a bottom surface 334 having landing pads 336. Solder balls 338 are disposed on landing pads 336. Landing pads 332 are configured to mate with bumped bond pads 310 that are disposed on semiconductor chip 302. It should be noted that
Liquid crystal polymer 322 is dispensed on top surface 330 of ball grid array substrate 306. Liquid crystal polymer 322 is partially cured at a temperature ranging from about 260° C. to about 280° C. for a time ranging from about 20 minutes to about 60 minutes under low pressure, e.g., about 100 psi (689 kPa). The partially cured liquid crystal polymer 322 is mated with semiconductor chip 302. The partial curing leaves liquid crystal polymer 322 tacky which promotes adhesion with ball grid array substrate 306. Semiconductor chip 302 is pressed against ball grid array substrate 306 and the combination of the semiconductor chip 302, liquid crystal polymer 322, and ball grid array substrate 306 undergo a heat treatment. The heat treatment bonds bumped bond pads 310 with landing pads 332 and cures liquid crystal polymer 322, thereby forming semiconductor component 300. It should be noted that heatsink 304 also serves as a lid to provide protection from physical and environmental stresses.
Referring now to
Packaging substrate 352 includes a plurality of leadframe leads 370-387 coupled to heatsink 354 through a thermally conductive liquid crystal polymer 364. Prior to singulation, leadframe leads 370-387 are part of a leadframe (not shown) in which leadframe leads 370-374 and 379-383 are on opposing sides of the leadframe and leads 375-378 and 384-387 are on opposing sides of the leadframe. The number of leads and the number of leads per side of packaging substrate 352 are not a limitation of the claimed subject matter.
Liquid crystal polymer 364 is preferably dispensed on leadframe leads 370-387 and partially cured by heating to a temperature ranging from about 260° C. to about 280° C. for a time ranging from about 20 minutes to about 60 minutes under low pressure, e.g., about 100 psi (689 kPa). The partial curing leaves liquid crystal polymer 364 tacky or sticky. The partially cured liquid crystal polymer 364 is mated with heatsink 354. Because liquid crystal polymer 364 is tacky, it adheres to heatsink 354. Pressure is applied to either the leadframe, the heatsink, or both, and the liquid crystal polymer is cured by, for example, being heated to a temperature ranging from about 280° C. to about 300° C. for a time period ranging from about 20 minutes to about 60 minutes under low pressure, e.g., about 100 psi (689 kPa). Curing liquid crystal polymer 364 forms an assembly containing a plurality of packaging substrates 352, wherein each packaging substrate includes leadframe leads, liquid crystal polymer 364, and a heatsink 354.
The assembly is singulated to form individual packaging substrates 352. After singulation, leadframe leads 370-387 are preferably flush with the sides of heatsink 354, i.e., leadframe leads 370-374 are flush with side 356, leadframe leads 375-378 are flush with side 362, leadframe leads 384-387 are flush with side 360, and leadframe leads 379-383 are flush with side 358.
Semiconductor chip 353 is mounted on heatsink 354. The backside or non-active side of semiconductor chip 353 may be electrically coupled to heatsink 354 or it may be coupled to heatsink 354 through an insulating material such as, for example, liquid crystal polymer. Leadframe leads 370-387 are coupled to bond pads 390 disposed on semiconductor chip 353 using, for example, wirebonds. It should be understood that the choice of which leadframe leads 370-387 to couple to which bond pads 390 is a design choice. For the sake of clarity, the wirebonds have not been shown in
It may be desirable to dispense a glob top material (not shown) over semiconductor chip 353 and leadframe leads 370-387. The glob top material can protect semiconductor chip 353 against mechanical and environmental stresses.
Optionally, heatsink 354 has fins similar to those described with reference to heatsink 304 shown in
By now it should be appreciated that a semiconductor component and a method for manufacturing the semiconductor component have been provided. In one or more embodiments, a cost effective method for packaging a semiconductor chip is implemented using batch processing steps for forming the packaging substrate rather than using individual assembly steps. Manufacture of semiconductor packages in accordance with one or more embodiments provides a high quality assembly that is repeatable. In addition, in one or more embodiments various heatsinking finned structures for removing heat from the semiconductor devices may be implemented.
Although certain example embodiments and methods have been disclosed herein, it will be apparent from the foregoing disclosure to those skilled in the art that variations and modifications of such embodiments and methods may be made without departing from the spirit and scope of the disclosed subject matter.
Claims
1-44. (canceled)
45. An apparatus, comprising:
- a heatsink having first and second major surfaces;
- a leadframe having at least one leadframe lead; and
- a liquid crystal polymer disposed on a portion of the at least one leadframe lead;
- wherein the liquid crystal polymer is mated to the heatsink.
45. An apparatus as claimed in claim 45, the heatsink comprising a platform that serves as a die receiving area.
46. An apparatus as claimed in claim 45, wherein the heatsink includes one or more fins extending from the second major surface thereof.
47. An apparatus as claimed in claim 45, wherein the heatsink includes one or more fins extending from the second major surface thereof, at least one or more of the fins having a quadrilateral shape.
48. An apparatus as claimed in claim 45, wherein the heatsink includes three or more fins extending from the second major surface thereof, three or more of the fins have a quadrilateral shape and are substantially parallel to each other.
49. An apparatus as claimed in claim 45, wherein the heatsink includes one or more fins extending from the second major surface thereof, wherein one or more of the fins has a pyramidal shape.
50. An apparatus as claimed in claim 45, wherein the leadframe comprises first and second opposing sides spaced apart from each other by a central area, wherein a first leadframe lead extends from the first side into the central area and a second leadframe lead extends from the second side into the central area.
51. An apparatus as claimed in claim 45, wherein the liquid crystal polymer has a ring-shaped pattern having first and second opposing sides and third and fourth opposing sides, and wherein the first side of the ring-shaped pattern is disposed on the first leadframe lead and the second side of the ring-shaped pattern is disposed on the second leadframe lead.
52. An apparatus as claimed in claim 51, wherein the first side of the ring-shaped pattern is disposed on a central portion of the first leadframe lead and the second side of the ring-shaped pattern is disposed adjacent an end of the ring-shaped pattern.
53. An apparatus as claimed in claim 45, wherein the leadframe has first and second opposing sides spaced apart from each other by a central area, wherein a plurality of leadframe leads extends from the first side into the central area and a plurality of lead extends from the second side into the central area.
54. An apparatus as claimed in claim 45, wherein the liquid crystal polymer is disposed in a ring-shaped pattern having first and second opposing sides and third and fourth opposing sides, and wherein the first side of the ring-shaped pattern is disposed on the plurality of leadframe leads extending from the first side of the leadframe and the second side of the ring-shaped pattern is disposed on the plurality of leadframe leads extending from the second side of the leadframe.
56. An apparatus as claimed in claim 53, wherein the leadframe further has third and fourth opposing sides spaced apart from each other by the central area, wherein a plurality of leadframe leads extends from the third side into the central area and a plurality of leadframe leads extends from the fourth side into the central area, and wherein the step of disposing the liquid crystal polymer includes disposing the third side of the ring-shaped pattern on the plurality of leadframe leads extending from the third side and disposing the fourth side of the ring-shaped pattern on the plurality of leadframe leads extending from the fourth side.
57. An apparatus as claimed in claim 45, further comprising:
- a semiconductor chip having first and second major surfaces, wherein a gate structure is formed over the first major surface; and
- wherein the first major surface of the semiconductor chip is coupled with the first major surface of the heatsink.
58. An apparatus as claimed in claim 57, wherein a metallization system is disposed on the first major surface of the semiconductor chip; and
- wherein the first major surface of the semiconductor chip is coupled with the first major surface of the heatsink via solder.
59. An apparatus as claimed in claim 58, wherein the metallization system comprises one of a tin-nickel-gold metallization system or a tin-nickel-silver metallization system, or combinations thereof.
60. An apparatus as claimed in claim 57, further comprising a metal clip coupled to the second side of the semiconductor chip and to a first leadframe lead of the plurality of leadframe leads.
61. An apparatus as claimed in claim 57, further comprising a lid disposed over the semiconductor chip, wherein a portion of the lid is coupled to the metal clip.
62. An apparatus as claimed in claim 57, further comprising:
- a metallization system on the second major surface of the semiconductor chip; and
- a metal clip soldered to the metallization system on the second major surface of the semiconductor chip.
63. An apparatus as claimed in claim 62, wherein the metallization system on the second major surface of the semiconductor chip comprises aluminum with a nickel-gold alloy disposed thereon.
64. An apparatus as claimed in claim 57, wherein the gate structure is electrically coupled to a second leadframe lead of the plurality of leadframe leads.
65. An apparatus as claimed in claim 64, wherein the lid is soldered to the semiconductor chip.
66. An apparatus as claimed in claim 57, further comprising at least one other semiconductor chip coupled to the heatsink.
67. An apparatus as claimed in claim 66, further comprising a switching chip and a mixed signal integrated circuit coupled to the heatsink.
Type: Application
Filed: Feb 25, 2009
Publication Date: Jun 18, 2009
Applicant: HVVI Semiconductors, Inc. (Phoenix, AZ)
Inventor: Jeanne S. Pavio (Paradise Valley, AZ)
Application Number: 12/392,391
International Classification: H01L 23/495 (20060101); H01L 23/36 (20060101);