JPH08213418A - Manufacture of semiconductor device and mold used for the manufacture thereof - Google Patents

Abstract

PURPOSE: To provide technology for preventing the warpage of a printed board in the case of manufacturing a semiconductor device in which a sealer made of resin is formed on one surface of the board. CONSTITUTION: A method for manufacturing a semiconductor device in which a sealer 3 made of resin 34 is formed on one surface of a printed board 2 comprises the steps of previously setting a protruding pedestal 35 substantially corresponding to a sealing unit for forming the sealer at the mold surface in direct contact with the board in a mold 25 used at the time of forming the sealer, and forming the sealer in the state that the board is inverted upside down at the time of clamping the mold 25. Even if the board is deformed due to the curing shrinkage of the resin after sealing, the board is molded in the state that the board is previously reversely warped, and hence the board becomes substantially flat due to the warpage by the shrinkage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device in which a sealing body made of resin is formed on one surface of a printed circuit board.
In particular, the present invention relates to a technique effectively applied to a manufacturing technique of a semiconductor device in which a sealing body is formed by transfer molding.

[0002]

2. Description of the Related Art As one of the sealing modes for semiconductor devices, L
CC (leadless-chip carrier) is known. This L
The CC is a CO that directly incorporates an IC chip or the like on a printed circuit board and covers the chip with a sealing body made of resin.
It has a B (chip on board) structure.

Regarding the LCC type hybrid IC based on a printed circuit board, "NEC Technical Report" Vol.47, No.3 1994, P31-P33 issued by NEC Corporation and "User's Manual" issued by NEC Corporation. , Material No. IEU-765C (4th edition), published November 1992,
P2 to P15.

The LCC according to the latter document describes a structure in which a sealing body is formed by injecting (potting) a resin inside a sealing frame body. Further, the same document describes the warp (corresponding to coplanarity) of the LCC type hybrid IC, and the warp amount is 100.
It is described that it is about (μm) or less.

Also, "VLSI Packaging Technology (below)" issued by Nikkei BP, issued May 15, 1993, P174 contains C
As the OB, a semiconductor device (BG) in which a molding material (sealing body) is formed on the main surface side of an epoxy substrate by transfer molding and a plurality of solder bumps are arranged and formed on the back surface thereof (BG
A: ball gried array) is disclosed.

[0006]

SUMMARY OF THE INVENTION The applicant of the present invention is
We are developing a technology to form a sealing body made of resin (resin) on one surface of a printed circuit board by the transfer molding method. In this case, when the size of the encapsulant is increased, the curing shrinkage amount of the resin at the time of transfer molding becomes large, and the warp amount of the printed circuit board becomes large. A printed circuit board with low rigidity causes a large amount of warpage. Moreover, the electrode terminal of LCC is provided in the periphery of a printed circuit board. Therefore, when the LCC is mounted on the wiring board, if the printed circuit board is warped, the electrode terminals of the LCC are not connected to the lands (electrodes) of the wiring board via solder.

The curing shrinkage rate of the resin varies depending on the material of the resin, but is, for example, about 2 to 3%. Therefore, an increase in the size of the semiconductor device increases the probability that the reliability of the connection of the electrode terminals at the time of mounting will be reduced.

An object of the present invention is to manufacture a semiconductor device in which a sealing body made of a resin is formed on one surface of a printed circuit board. After the sealing, the peripheral portion of the printed circuit board can be manufactured flat without warping. It is to provide a manufacturing technology of a device.

Another object of the present invention is to manufacture a semiconductor device in which a sealing body made of a resin is formed on one surface of a printed board, and the peripheral portion of the printed board is manufactured flat without being warped after sealing. It is to provide a mold that can be molded.

The above and other objects and novel characteristics of the present invention will be apparent from the description of the present specification and the accompanying drawings.

[0011]

The outline of the representative ones of the inventions disclosed in the present application will be briefly described as follows. That is, the method for manufacturing a semiconductor device of the present invention is a method for manufacturing a semiconductor device in which a sealing body made of a resin is formed on one surface of a printed circuit board by using a transfer molding method, and is used when the sealing body is formed. In the molding die of the present invention, a protrusion pedestal substantially corresponding to the sealing portion forming the sealing body is provided in advance on the surface of the molding die that is in direct contact with the printed circuit board, and when the mold die is clamped, The structure is such that the sealing body is formed while the substrate is warped. The height of the protrusion pedestal is such that the warp of the printed board due to the curing shrinkage of the sealed body after formation of the sealed body is changed to the opposite direction and the printed board is returned to a flat state. In addition, the projection pedestal is a flat surface and the periphery is a surface that draws a gentle curve, and the edge of the projection pedestal is located inside the edge of the sealing body.

The transfer mold of the present invention is a mold for clamping a printed circuit board between a lower mold and an upper mold to form a resin sealing body on one surface of the printed circuit board. A projection pedestal is provided on the mold surface that is in direct contact with the printed circuit board, the projection pedestal corresponding to the sealing portion forming the sealing body and having the outer peripheral edge located within the desired length from the edge of the sealing portion. It has a structure.

[0013]

According to the above-mentioned means, in the transfer molding method for manufacturing a semiconductor device of the present invention, in the molding die used at the time of transfer molding, the sealing portion is provided on the surface of the molding die which is in direct contact with the printed board. Since the protruding pedestal, which corresponds to the above and whose outer peripheral edge is located inside the desired length from the sealing portion, is provided, the printed circuit board is transfer-molded in a warped state when the mold is clamped. The printed board, on the contrary, is warped and flattened by the curing shrinkage of the sealing body made of resin after molding.

The mold for transfer molding according to the present invention has a structure in which a sealing body is formed on one surface of a printed circuit board by a transfer molding method after clamping, and the mold surface directly contacting the printed circuit board has the above structure. Since the protrusion pedestal is provided corresponding to the sealing portion forming the sealing body and having the outer peripheral edge located inside the edge of the sealing portion by a desired length, the mold of the mold is formed. When tightened, it has a structure that allows the printed circuit board to warp. Therefore, in the semiconductor device manufactured by transfer molding by using the molding die of the present invention, after the transfer molding, even if the printed circuit board is warped even if the sealing body made of the resin cures and shrinks,
Since the mold is clamped so as to be warped in the opposite direction so as to eliminate the warping caused by the curing shrinkage, the printed circuit board in a product state after transfer molding becomes flat.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a semiconductor device manufacturing method of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of an essential part showing a method for manufacturing a semiconductor device (LCC) according to an embodiment of the present invention, and FIG. 2 is an exploded cross-sectional view of an essential part showing a printed board on which components are mounted and a molding die. FIG. 3 is a schematic plan view showing a lower die of a molding die, a printed board, and a pedestal pedestal portion provided on the bottom of the lower die. FIG. 4 is manufactured by a method for manufacturing a semiconductor device according to an embodiment of the present invention. Schematic sectional view showing the outline of LCC, FIG. 5 is an actual LC
FIG. 7 is a schematic perspective view showing a main part of C, FIG. 6 is a schematic sectional view showing a mounted state of the LCC manufactured according to this embodiment, and FIG.
FIG. 3 is a perspective view showing a part of the same.

In this embodiment, an example in which the present invention is applied to a method for manufacturing an LCC (semiconductor device), that is, a transfer molding method for an LCC will be described.

LC manufactured by the manufacturing method of the present invention
The C (semiconductor device) 1 will be briefly described. LCC1
As shown in FIGS. 4 and 5, the external appearance is composed of a printed circuit board 2 and a sealing body 3 made of a resin formed on the main surface of the printed circuit board 2. Printed circuit board 2
Has a thickness of, for example, 0.6 mm, and its size is 25 mm □. In addition, the sealing body 3
Has a thickness of several mm, and its size is 20 mm.
□

The printed circuit board 2 has desired wirings 4 (the wirings on the back surface are not shown) formed on the main surface and the back surface. As shown in FIG. 5, in the wiring 4 on the main surface of the printed circuit board 2 which is separated from the sealing body 3, the printed matter is printed through the conductor layer 5 provided in the through hole formed so as to penetrate the printed circuit board 2. It is electrically connected to the electrode terminals 6 on the back surface of the substrate 2. The electrode terminal 6 is a printed circuit board 2
From the side surface to the main surface (upper surface) of the printed circuit board 2.

A desired electronic component is mounted on the main surface portion of the printed circuit board 2 covered with the sealing body 3. As a desired electronic component, for example, as shown in FIG. 4, an LSI chip 7 or an IC chip 8 is fixed as an active component, and a chip capacitor 9 is incorporated as an active component. Electrodes (not shown) of the LSI chip 7 and IC chip 8 and wiring (not shown) of the printed circuit board 2 are electrically connected by a conductive wire 10.

On the other hand, this is one of the features of the present invention. As shown in FIG. 4, a slight recess 15 is formed on the back surface of the printed board 2 and the peripheral portion of the printed board 2 is formed. Has a flat surface 16. That is, the electrode terminals 6 arrayed and formed on the back surface side of the printed circuit board 2 are located on substantially the same plane.

As a result, as shown in FIGS. 6 and 7,
When the LCC 1 manufactured according to the present invention is mounted on the wiring board 17, the printed board 2 is warped as in the conventional case because the periphery of the printed board 2 is the flat surface 16 which is substantially the same plane. Of course, the electrode terminals 6 formed on the flat surface 16 are securely fixed to the wirings 18 provided on the main surface (upper surface) of the wiring board 17 via the solder 19.

Next, the production of the LCC1 will be described. As shown in FIG. 2, a printed circuit board 2 on which an LSI chip 7, an IC chip 8, a chip capacitor 9 and the like are mounted is prepared and, as shown in FIG. 1, is clamped in a molding die 25 of a transfer molding apparatus. Mold die 2
As shown in FIG. 2, 5 includes a lower mold 26 and an upper mold 27, and a housing recess 29 for housing the printed circuit board 2 is provided on the parting surface 28 side of the lower mold 26. .

Also, the upper mold 2 corresponding to the accommodation recess 29.
On the parting surface 30 of FIG. 7, a cavity 31 as a space to be molded, which is a depression, a runner 32 for guiding the melted resin, and a narrowed gate 33 which is the tip of the runner 32 and is continuous with the cavity 31.
Is provided.

On the other hand, this is one of the features of the present invention. As shown in FIGS. 2 and 3, a projection pedestal 35 is provided at the bottom of the accommodation recess 29 of the lower mold 26. The depth of the accommodation recess 29 is substantially the same as or slightly smaller than the thickness of the printed circuit board 2. This is because the melted resin is lower mold 26 and upper mold 27 during transfer molding.
This is to prevent the resin from flowing out between the parting surfaces 28 and 30 of the.

The height of the protrusion pedestal 35 is, for example,
It is about 0.1 mm, and its peripheral edge is positioned a few millimeters inside the edge of the sealing portion (cavity 31) for forming the sealing body 3. In this way, by making the edge of the protrusion pedestal 35 inside by a few millimeters from the edge of the cavity 31, the flattening of the printed board 2 due to the curing shrinkage of the sealing body after transfer molding becomes more reliable.

FIG. 1 shows an LSI chip 7, an IC chip 8,
This shows a state in which the printed circuit board 2 on which the chip capacitors 9 and the like are mounted is clamped by the molding die 25, and the melted resin 34 (the dotted region in the figure) is injected into the cavity 31 from the gate 33. In this state,
The printed circuit board 2 which is a flat plate is clamped so that it can be warped so that the central portion thereof rises due to the presence of the protrusion pedestal 35 provided on the bottom of the molding die 25. The amount of warpage is set so that at least the peripheral portion of the printed circuit board 2 is flattened by the warpage of the printed circuit board 2 due to the curing shrinkage of the resin (sealing body 3) after transfer molding.

In the semiconductor device (LCC) manufactured in this embodiment, after the printed circuit board is clamped in the molding die, a sealing body made of resin is formed on one surface side of the printed circuit board by transfer molding. At the time of this transfer molding, in the molding die used, a projection pedestal corresponding to the sealing portion and having an outer peripheral edge located at a desired length inside the sealing portion is provided on the molding die surface which is in direct contact with the printed circuit board. The structure is provided.
Therefore, when the mold is clamped, the printed circuit board is transfer-molded in a warped state, so even if the printed circuit board warps backward due to curing shrinkage of the resin encapsulant after transfer molding, the printed circuit board is warped in advance. On the contrary, since it is bent back, the peripheral portion of the printed circuit board is flattened. As a result, when the LCC manufactured according to the present invention is mounted on the wiring board, the LC
Each electrode terminal of C is surely connected to the electrode of the wiring board through a bonding material such as solder.

The mold for transfer molding according to the present invention has a structure in which a sealing body is formed on one surface of a printed circuit board by a transfer molding method after clamping, and the mold surface directly contacting the printed circuit board has the above structure. Since the protrusion pedestal is provided corresponding to the sealing portion forming the sealing body and having the outer peripheral edge located inside the edge of the sealing portion by a desired length, the mold of the mold is formed. When tightened, it has a structure that allows the printed circuit board to warp. Therefore, in a semiconductor device manufactured by transfer molding by using this molding die, even if the printed circuit board warps due to curing shrinkage of the resin encapsulant after transfer molding, the warping due to the curing shrinkage may occur. In order to solve the problem, the mold is clamped so as to warp in the opposite direction, so that the printed circuit board becomes a flat product after transfer molding.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say. For example,
In the above embodiment, the protrusion height of the protrusion pedestal 35 is set to about 0.1 mm, but this is the case where the printed circuit board 2 is a glass / epoxy resin substrate and has a thickness of 0.6 mm. Therefore, the thickness and material (rigidity,
It is necessary to properly select the thickness and size of the protrusion pedestal 35 depending on the coefficient of thermal expansion and the like. For example, thickness 0.8
In the case of a glass / epoxy resin substrate of mm, the protrusion height of the protrusion pedestal 35 is appropriately about 0.15 mm.

In the above description, the LCC, which is the field of application of the invention mainly made by the present inventor, was the background.
However, the present invention is not limited to this, and a ball grid array (BGA) type semiconductor having a sealing body on one surface of a printed circuit board and a plurality of protruding electrodes on the other surface thereof. The same can be applied to the manufacturing technology of the device. In this case, the protruding electrode is formed after forming the sealing body. INDUSTRIAL APPLICABILITY The present invention can be applied to at least a technique of forming a sealing body made of a resin on one surface of a printed board.

[0031]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows. In the method for manufacturing a semiconductor device (LCC) of the present invention, a mold die having a protruding pedestal that directly contacts the printed circuit board is used in consideration of the curing shrinkage of the sealing body after transfer molding. The mold is clamped by bending back the printed circuit board in a direction opposite to the direction in which the printed circuit board warps when the encapsulant cures and shrinks. Therefore, the peripheral part of the printed circuit board of the LCC after transfer molding becomes a flat surface,
The reliability of mounting on the wiring board is increased.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing a method for manufacturing an LCC according to an embodiment of the present invention.

FIG. 2 is an exploded cross-sectional view of essential parts showing a printed board on which components are mounted and a molding die in the method for manufacturing an LCC according to the present embodiment.

FIG. 3 is a schematic plan view showing a lower die of a molding die in the present embodiment, a printed circuit board, and a protruding pedestal portion provided on the bottom of the lower die.

FIG. 4 is a schematic cross-sectional view showing the outline of an LCC manufactured by the method for manufacturing a semiconductor device of this embodiment.

FIG. 5 is a schematic perspective view showing a main part of an actual LCC manufactured by the method for manufacturing a semiconductor device of this embodiment.

FIG. 6 is a schematic cross-sectional view showing a mounted state of an LCC manufactured by the method for manufacturing a semiconductor device of this embodiment.

FIG. 7 is a perspective view showing a part of a mounted state of an LCC manufactured by the method for manufacturing a semiconductor device of this embodiment.

[Explanation of symbols]

1 ... LCC, 2 ... Printed circuit board, 3 ... Sealing body, 4 ... Wiring, 5 ... Conductor layer, 6 ... Electrode terminal, 7 ... LSI chip, 8
... IC chip, 9 ... Chip capacitor, 10 ... Wire,
15 ... Dimple, 16 ... Flat surface, 17 ... Wiring board, 18 ... Wiring, 19 ... Solder, 25 ... Mold die, 26 ... Lower die, 2
7 ... Upper mold, 28 ... Parting surface, 29 ... Housing recess, 3
0 ... parting surface, 31 ... cavity, 32 ... runner, 33 ... gate, 34 ... resin, 35 ... projection pedestal.

Claims (4)

[Claims] 1. A method of manufacturing a semiconductor device, wherein a sealing body made of a resin is formed on one surface of a printed circuit board, wherein a mold used in forming the sealing body is a mold which is in direct contact with the printed circuit board. A protrusion pedestal that substantially corresponds to the sealing portion that forms the sealing body is provided on the die surface in advance, and the sealing body is formed while the printed circuit board is warped when the mold die is clamped. A method of manufacturing a semiconductor device, comprising: 2. The height of the projection pedestal is such that the warp of the printed circuit board due to curing shrinkage of the sealed body after formation of the sealed body is changed to the opposite direction to return the printed circuit board to a flat surface. The method of manufacturing a semiconductor device according to claim 1, wherein 3. The projection pedestal has a flat surface, and
2. The method of manufacturing a semiconductor device according to claim 1, wherein the periphery is a surface having a gentle curved line, and the edge of the protrusion pedestal is located inside the edge of the sealing body. 4. A mold die for clamping a printed circuit board between a lower mold and an upper mold to form a resin sealing body on one surface of the printed circuit board, which is in direct contact with the printed circuit board. A mold base corresponding to a sealing part forming the sealing body on a mold surface and provided with a projection pedestal having an outer peripheral edge located inside a desired length from an edge of the sealing part. Type.