INTEGRATED CIRCUIT PACKAGE MOLD ASSEMBLY
An integrated circuit (“IC”) package mold includes an upper mold platen that defines an upper mold cavity for receiving an upper substrate having a die attach side with a plurality of dies mounted thereon and a non-attach side with no dies mounted thereon. The die attach side of the upper substrate faces upwardly. A lower mold platen defines a lower mold cavity for receiving a lower substrate having a die attach side with a plurality dies mounted thereon and a non-attach side with no dies mounted thereon. The die attach side of the lower substrate faces downwardly.
Integrated circuits, also referred to as “IC's” or “semiconductor chips” or simply “chips,” are electronic circuits made by diffusion of trace elements into the surface of thin substrates of semiconductor material. Integrated circuits were first produced in the mid 20th Century. Because of their small size and relatively low production cost, integrated circuits are now used in most modern electronics. Semiconductor chips are typically mass produced in the form of a single wafer that contains a large number of identical integrated circuits. The wafer is cut (“singulated”) into a number of individual semiconductor chips referred to as “dies” or “dice.”
Dies and sometimes other components such as passive devices are “packaged” to prevent damage to the dies and to facilitate attachment of the dies to circuit boards. Various packaging materials and processes have been used to package integrated circuit dies. One conventional packaging method involves mounting individual dies in a predetermined pattern on a substrate strip. The dies mounted on the substrate strip are then encapsulated in a plastic material, such as by a transfer molding process. Next, the encapsulated dies are singulated into individual integrated circuit packages by cutting the encapsulated die/substrate strip in accordance with the predetermined die mounting pattern. Typical cutting tools include saws and punches. Each integrated circuit package generally includes at least one die and the underlying portion of the substrate strip on which it was mounted. The underlying substrate strip is sometimes a leadframe to which the die is electrically connected.
SUMMARYAn integrated circuit (“IC”) package mold assembly includes an upper mold platen defines an upper mold cavity for receiving an upper substrate having a die attach side with a plurality of dies mounted thereon and a non-attach side with no dies mounted thereon. The die attach side faces upwardly. A lower mold platen defines a lower mold cavity for receiving a lower substrate having a die attach side with a plurality dies mounted thereon and a non-attach side with no dies mounted thereon. The die attach side of the lower substrate faces downwardly.
Each of the dies 24, 26, 28 is electrically connected to an associated leadframe portion 25, 27, 29 of the leadframe sheet 22. In the assembly 10 of
After insertion of the leadframe sheet 22 and attached wire bonded dies 24, etc., the mold 10 is closed and the mold cavity 16 is filled with molten mold compound 40. The mold compound 40 flows under pressure into the cavity 16 through the runner 18, which is conventionally connected to a pressurized source of molten mold compound 40. After the mold compound 40 has filled the cavity, curing of the mold compound commences, initially while the mold 10 is closed, and subsequently after it is has been opened and the entire assembly of leadframe sheet 22, dies 24, etc. and mold compound 40 has been removed. After removal from the mold 10, the portion of the mold compound 40 that was in the runner 18 is removed from the portion of the mold compound covering the leadframe sheet 22. The portion of the mold compound that was in the runner is scrapped as waste. This waste is typically around 40% of the total amount of mold compound injected in a molding operation.
After the molded leadframe assembly has completed curing it is singulated along saw streets 36, 38, etc., indicated by dashed lines in
The mold assembly 110 includes an upper substrate 122, which may be a leadframe sheet substrate. Hereafter “leadframe sheet substrate” is referred to by the shorter phrase “leadframe sheet.” It is to be understood that substrates other than leadframe sheets may be used in the embodiments described in
The substrate 122 has a first end 124 and a second end 126 and has a die attach side 128 and an opposite or “non-attach side” 129. A lower substrate 132, which in this embodiment may be a leadframe sheet, has a first end 134 and a second end 136 and also includes a die attach side 138 and an opposite or non-attach side 139. The upper substrate 122 and the lower substrate 132 each comprise a plurality of corresponding separate substrate portions 140 and 142, respectively, which are vertically aligned.
The mold assembly 110 also includes upper and lower substrate dies. The upper substrate dies 152 are mounted on the upper substrate portions 140 of the upper substrate 124 and are electrically connected thereto, as by upper bond wires 154. Similarly lower substrate dies 162 are attached to the separate substrate portions 142 of the lower substrate 134 and are connected thereto by lower leadframe bond wires 164. As illustrated in
As further illustrated by
Next the upper and lower molded substrates 122, etc., 132, etc., are separated and the liner 170, if used, is removed. Each substrate 122, etc., 132, and associated dies and mold compound, etc., is then singulated by conventional methods to provide a plurality of separate IC packages.
With reference to
The prior art structure, as shown by
This clamping assembly 317, 319 vertically supports the leadframes 322, 332, counteracting a tendency of the leadframes to droop under their own weight prior to the inflow of mold compound (not shown in
As used herein terms such as up, down, above, under, vertical, horizontal, etc., are used in a relative sense to explain the physical relationship between various structures shown in the drawings, rather than in an absolute sense indicating an orientation of objects within a gravitational field.
Certain specific embodiments of double cavity mold assemblies and methods of use thereof have been expressly described in detail herein to aid those reading this disclosure to understand the inventive concepts involved. Alternative embodiments of such mold assemblies and methods will occur to those skilled in the art after reading this disclosure. It is intended that the language of the appended claims be broadly construed to cover such alternative embodiments, except as limited by the prior art.
Claims
1. An integrated circuit (“IC”) package mold assembly comprising:
- an upper mold platen defining an upper mold cavity for receiving an upper substrate having a die attach side with a plurality of dies mounted thereon and a non-attach side with no dies mounted thereon, wherein said die attach side is facing upwardly; and
- a lower mold platen defining a lower mold cavity for receiving a lower substrate having a die attach side with a plurality dies mounted thereon and a non-attach side with no dies mounted thereon, wherein said die attach side of said lower substrate is facing downwardly.
2. The assembly of claim 1 wherein said upper and lower mold platens comprises at least one pair of aligned projections extending into said mold cavities for engaging said upper and lower substrates therebetween.
3. The assembly of claim 1 further comprising a single runner in fluid communication with said upper and lower mold cavities.
4. An integrated circuit (“IC”) package mold assembly comprising:
- an upper mold platen defining an upper mold cavity;
- a lower mold platen defining a lower mold cavity;
- an upper substrate positioned in said upper mold cavity and having a plurality of integrally connected substrate portions, each said upper substrate portion having a die attach side and a non-attach side, IC dies being mounted on said die attach sides of said plurality of upper substrate portions; and
- a lower substrate positioned in said lower mold cavity and having a plurality of integrally connected lower substrate portions, each lower substrate portion having a die attach side and a non-attach side, IC dies being mounted on said die attach sides of said plurality of lower substrate portions;
- wherein said upper and lower substrates are positioned with said non-attach sides of said substrate portions thereof positioned in facing relationship.
5. The assembly of claim 4 wherein said upper and lower substrates comprise upper and lower leadframe substrates and further comprising a liner positioned between said upper and lower leadframe substrates.
6. The assembly of claim 4 wherein said upper and lower substrates comprises nFBGA (New Fine Pitch Ball Grid Array) substrates.
7. The assembly of claim 4 wherein said upper and lower substrates comprises flex-tape substrates.
8. The assembly of claim 4 wherein said upper and lower substrates have aligned holes extending therethrough.
9. The assembly of claim 8 further comprising a liner positioned between said upper and lower substrates and having holes therein aligned with said holes in said upper and lower substrates.
10. The assembly of claim 9 wherein each of said upper and lower substrates comprise leadframe sheet substrates with leadframe corner connection structures that connect leadframe portions on each corresponding leadframe sheet substrate;
- wherein said leadframe corner connection structures have openings therein that are aligned with corresponding ones of said holes extending through said liner.
11. The assembly of claim 8, said upper and lower mold cavities being filled with mold compound that fills said aligned holes extending through said substrates.
12. A method of making integrated circuit (“IC”) packages comprising:
- placing first and second IC package substrates having a plurality of individual portions associated with individual IC packages in non-attach side facing, mirror image relationship;
- placing the first and second substrates in a mold having upper and lower cavities with the first substrate positioned in an upper mold platen cavity and the second substrate positioned in a lower mold platen cavity that is in fluid communication with the upper mold platen cavity; and
- filling the upper and lower mold cavities with molten mold compound.
13. The method of claim 12 further comprising engaging aligned portions of the first and second IC package substrates with opposite mold platen projections.
14. The method of claim 13 further comprising producing a plurality of holes extending through aligned portions of the first and second substrates.
15. The method of claim 14 further comprising flowing mold compound into the mold to mold the two substrates including flowing mold compound through the plurality of holes to form connecting structures to hold the two molded substrates together.
16. The method of claim 15 further comprising:
- curing the mold compound; and
- removing connecting structures holding the molded substrates together.
17. The method of claim 16 further comprising separating the molded substrates.
18. The method of claim 17 further comprising dicing the separated molded substrates.
19. The method of claim 15 further comprising dicing the connected molded substrates.
20. The method of claim 19 further comprising removing the connecting structure during said dicing.
Type: Application
Filed: Oct 12, 2015
Publication Date: Apr 13, 2017
Inventor: Hiep Xuan Nguyen (Grand Prairie, TX)
Application Number: 14/880,976