JP2003158143A - Molding method of thin semiconductor device and molding die therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the molding method of a thin semiconductor device, and a molding die for the same capable of surely flattening the thin semiconductor device having a tendency of warping after molding in the case of a thin semiconductor device package molded with a thermosetting resin. SOLUTION: The molding die 80 is constituted of a bottom metal mold 81 and a top metal forth 82. The cavity 811 of the bottom mold 81 is formed so as to have a protruded curved surface with a curvature capable of molding with a reverse warpage, the same as the warpage of the package 30 which is generated by a curing contraction upon curing the molded resin R in the case of forming the package 30, by molding a semiconductor element S and a wiring substrate 10 with a resin R. The cavity 821 of the top mold 82 is opposed to the whole surface of the protruded curved surface 811 at a predetermined depth and the recessed curved surface 822 is formed with the same curvature as that of the protruded curved surface 811.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a thin semiconductor device in which a resin package is formed on one surface of a semiconductor element and a wiring board on which the semiconductor element is mounted, and a molding die thereof.

[0002]

2. Description of the Related Art First, a conventional thin semiconductor device will be described.

FIG. 4 is a main manufacturing process diagram for explaining a conventional method of manufacturing a thin semiconductor device, FIG. 5 is a partial sectional view of a molding die used for a resin package of a conventional thin semiconductor device, and FIG. Is a partial cross-sectional view showing a state of molding using the molding die shown in FIG. 5, FIG. 7 is a cross-sectional view showing a state of mounting a conventional thin semiconductor device on a mother substrate, and FIG. FIG. 9 is a cross-sectional view showing the structure of another mold die of the technology, FIG. 9 is a cross-sectional view showing a state in which various parts mounted on a printed circuit board are molded using the mold die shown in FIG. 10 is a sectional view of a conventional thin semiconductor device molded by the molding die shown in FIG.

As one of the package (sealing) forms of the conventional thin semiconductor device, a so-called Amkor company or the like which has a thin semiconductor element incorporated in a wiring board and is packaged (sealed) with resin from one side is commercialized. Are known.

Such a thin semiconductor device can be obtained through the main steps as shown in FIG. That is, first,
In the die bonding step shown in FIG. 4A, the thin semiconductor element S is fixed to the wiring board 10. The wiring board 10 is provided with a cavity 11 for incorporating the thin semiconductor element S, and circuit wirings 12 and the like corresponding to the electrodes of the thin semiconductor element S to be mounted on the periphery thereof. Temporary fixing tape 2 provided with an adhesive layer on the back surface of 10 in advance
0 is pasted. The semiconductor element S has a cavity 1
Die-bonding to the temporary fixing tape 20 exposed at No. 1 using the adhesive layer.

Next, in the wire bonding process shown in FIG. 4B,
Circuit parts 12 of the thin semiconductor element S and the wiring board 1
And are connected using a wire W such as a gold wire.

Then, in a molding step shown in FIG. 4C, a resin (not shown) is used to mold the surface of the wiring substrate 10, the thin semiconductor element S, and the wire W from the side where they are present to the resin R. Then, the package 30 is molded.

Then, in the tape peeling step shown in FIG. 4D, the temporary fixing tape 2 is removed from the molded wiring board 10.
0 is peeled off and removed.

Next, in a solder ball forming step shown in FIG. 4E, a solder ball 14 is formed on the surface of the via hole 13 which is electrically connected to the circuit wiring 12 and penetrates the back surface of the wiring substrate 10. The solder ball 14 is an effective structure for improving the reliability of mounting the set on a mother board (not shown). However, in a small package, a stable mounting plane can be secured. There is also.

Finally, in the thinning step shown in FIG. 4F, a plurality of final thin semiconductor devices 1B are cut out from a large-sized wiring board. This is the conventional thin semiconductor device 1B. Usually, in order to improve productivity, a plurality of semiconductor devices 1B are formed on one large-sized wiring board. The thickness of such a thin semiconductor device 1B is about 300 μm or less.

The molding of FIG. 4C is performed using a molding die as shown in FIG.

The molding die 40 is composed of a lower die 41 and an upper die 42. The lower die 41 covers the semiconductor substrate S or the semiconductor element S and the temporary fixing tape 20 on the cavity surface of the cavity substrate, and covers the semiconductor element S. A part of the circuit wiring 12 to which the wire W is connected is molded. A hollow cavity 411 corresponding to the area of the wiring substrate 10 that must be formed is formed.

The upper mold 42 has a cavity 421 formed on the cavity surface thereof at least slightly higher than the height of the wire W and having an area including the portion where the wire W is connected to the wiring circuit 12 on the wiring board 10. ing. Further, a gate 422 for injecting the molten resin R is formed.

Using the molding die 40 having such a structure, as shown in FIG. 6, the wire-bonded semiconductor element S fixed to the temporary fixing tape 20 shown in FIG. 4B.
The wiring board 10 and the wiring board 10 are placed in the cavity 411 of the lower mold 41, the upper mold 42 is covered and clamped thereon, and in that state, the thermosetting molten resin R is injected from the gate 422, and wiring is performed. When the semiconductor element S and the wire W are covered on one surface of the substrate 10 and cured, the package 30 is formed and the thin semiconductor device 1B is obtained.

This molding method is generally called a transfer molding method, and the molding die 40 is
This is a method of injecting a thermosetting resin R in a state of being heated to around 0 ° C. and molding. In the packaging technology in which the package 30 made of the resin R is formed on one surface of the wiring board 10 by the transfer molding method, the wiring board 10, the semiconductor element S, and the like are heated at a high temperature of about 180 ° C. during molding. Since it is hardened by the curable resin R, after being cured, when it is taken out from the molding die 40 and reaches room temperature, as shown in FIG.
0, the semiconductor element S (silicon), and the thermosetting resin R (for example, epoxy resin) have different thermal expansion coefficients and the thermosetting resin R itself cures and shrinks, so that the thin semiconductor device 1B centering on the package 30 is provided. The problem of warping arises.

Therefore, the warp generated in this molding process causes a handling error in the subsequent process, which leads to a decrease in productivity, but the biggest problem is that the mother on the electronic equipment side as shown in FIG. The problem is that when the semiconductor device 1B is mounted on the substrate 50, the thin semiconductor device 1B is warped, resulting in frequent connection failures.

The amount of warpage of the package 30 increases as the size of the semiconductor element S, which is the object to be molded, increases and as it decreases in thickness. The warp that remarkably occurs in such a large-sized and thinned thin semiconductor device 1B is caused when the mother board 50 is mounted on the mother board 50 of the electronic device.
Connection to the electrode terminals, and significantly lower the reliability.

As shown in FIG. 10, the warp as described above is caused by the LSI chips 62, I on the printed circuit board 61.
It is said that this also occurs when a semiconductor device 1C such as a resin-molded LCC (leadless chip carrier) is obtained by mounting a C chip 63, a chip capacitor 64 and the like. A technique for correcting the warp in such a case is disclosed in JP-A-8-213418. The mold for that purpose is shown again in FIGS. 8 and 9. However, it should be noted in advance that the reference numerals attached to these drawings are different from the reference numerals attached to the drawings disclosed in the publication.

As shown in FIG. 8, this molding die 7
0 is also composed of a lower mold 71 and an upper mold 72.

The lower die 71 has a protrusion pedestal on the surface forming a cavity 711 in which the printed circuit board 61 portion on which components such as the LSI chip 62, the IC chip 63, and the chip capacitor 64 to be molded are mounted. 71
2 has a structure formed.

One upper mold 72 has a structure in which a cavity 721 having a depth about twice the thickness of the various components and the printed circuit board 61 is formed on the cavity surface corresponding to the various components. It is a thing. The upper mold 72 is also formed with a gate 722 leading to the cavity 721 and a runner 723 leading to the gate 722.

As shown in FIG. 9, the projection pedestal 712 of the cavity 711 of the lower mold 71 having the above structure is
The printed circuit board 61 portion on which the above-mentioned various components are mounted is placed, and the upper mold 721 is placed thereon to be clamped, and then the molten thermosetting resin R is injected into the cavity through the runner 723 and the gate 722. Then, after the mold die 70 and the like are cooled, the mold die 7 is cooled.
When the object to be molded is taken out from 0, a semiconductor device 1C is obtained in which the printed circuit board 61 has a trapezoidal warp in the direction opposite to the warp that normally occurs when molding is performed using the molding die 40 shown in FIG.

In this way, even if the printed circuit board 61 warps due to the thermosetting resin R of the package 65 of the semiconductor device 1C in which the printed circuit board 61 warps in a trapezoidal shape, the printed circuit board 61 warps back in advance. Since it has a different shape, the printed circuit board 61 is said to be substantially flat due to the warp due to the curing shrinkage.

[0024]

However, as is clear from the structure shown in the figure, the semiconductor device 1C of the prior art has: Various parts (62, 63, 64) are printed circuit boards 61
It is implemented on 2. 2. Only the printed circuit board 61 in which the various components are mounted is formed in a trapezoidally deformed structure rather than being warped. 3. The thickness of the package 65 that covers the tops of the various components is approximately twice the height of the various components. Since the package 65 that covers the tops of various components is molded in a trapezoidal cross-section, the warpage of the printed circuit board 61 portion due to the curing shrinkage of the conventional thermosetting resin R is prevented by the disclosed technology of the present invention. It is very difficult to flatten with a warped structure.

Therefore, the present invention is intended to solve such a problem, and even in a thin semiconductor device in which a package molded with a thermosetting resin is formed,
An object of the present invention is to obtain a molding method for a thin semiconductor device and a molding die for the thin semiconductor device, which can surely flatten and mold a thin semiconductor device that is going to warp.

[0026]

Therefore, in the molding method for a thin semiconductor device of the present invention, the semiconductor element and the wiring board on which the semiconductor element is to be mounted are arranged so as to form substantially the same surface, In a method for molding a thin semiconductor device in which a resin package is formed on one surface of a wiring board to which electrodes of the semiconductor element are connected, a package is formed by molding the semiconductor element and the wiring board with a thermosetting resin. In this case, the warpage of the package caused by curing shrinkage when the molded thermosetting resin is cured is expected in advance, and the semiconductor element and the wiring board are warped with the same warpage as the warpage. The above problem is solved by adopting a resin molding method.

Further, in the mold die for a thin semiconductor device of the present invention, the semiconductor element and the wiring board on which the semiconductor element is to be mounted form substantially the same surface between the lower die and the upper die. In a mold die for a thin semiconductor device for forming a resin package on one surface of a wiring board to which electrodes of semiconductor elements are connected, the cavity surface of the lower die is convex with a predetermined curvature. The cavity surface of the upper mold faces the entire surface of the convex curved surface at the predetermined depth, and the concave curved surface has the same curvature as that of the convex curved surface. The above problem is solved by adopting the structure formed in the above.

The curvature of the convex curved surface and the concave curved surface in the case of this molding die is such that when the semiconductor element and the wiring board are molded with resin to form a package, the molded resin is cured. It is desirable that the curvature is such that the mold can be molded with a reverse warp equivalent to the warp of the package caused by the shrinkage upon curing.

Therefore, according to the method for molding a thin semiconductor device of the present invention, at least a package in which a semiconductor element is molded can be molded with a uniform thickness, and when the temperature returns to room temperature after the molding, the package warps. Can be easily turned back and the package, and the semiconductor device molded therein, can be maintained substantially flat.

Further, according to the molding die for a thin semiconductor device of the present invention, the package covering at least the semiconductor element portion can be molded with a thin and uniform thickness, and when the temperature returns to room temperature after the molding. In addition, it is possible to mold the package with a curvature that can easily reverse the warp of the package.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION A molding method for a thin semiconductor device and a molding die thereof according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a partial cross-sectional view showing the structure of a molding die for a thin semiconductor device according to an embodiment of the present invention, and FIG. 2 is a plan view of a thin semiconductor device molded using the molding die shown in FIG. FIG. 3 is a partial cross-sectional view of the molding die and the thin semiconductor device showing the state in which the molding die and the thin semiconductor device molded using the molding die of FIG. 1 are mounted on the mother substrate. It is a sectional view of a semiconductor device and a mother substrate.

First, the structure and construction of a thin mold semiconductor device mold according to an embodiment of the present invention will be described with reference to FIG.

Reference numeral 80 indicates a molding die for a thin semiconductor device according to an embodiment of the present invention. The molding die 80 is composed of a lower die 81 and an upper die 82.

The lower die 81 has a cavity 811 formed in a convex curved surface 812 with a predetermined curvature, and the upper die 82 has a cavity 821 having a predetermined depth in the convex curved surface 811. The convex curved surface 8 facing the entire surface and
It has a structure formed on the concave curved surface 822 with the same curvature as that of No. 11. The upper mold 82 is also formed with a gate 823 communicating with the cavity 821 and a runner 824 communicating with the gate 823.

The curvatures of the convex curved surface 812 and the concave curved surface 822 of the lower die 81 are the same when the semiconductor element S to be molded and the wiring substrate 10 are molded with the resin R to form the package 30. Package 30 which is produced by curing shrinkage when the molded resin R is cured
The curvature should be such that it can be molded with a reverse warpage equivalent to that of.

The molding method of the thin semiconductor device of the present invention is performed using such a molding die 80. That is, FIG.
As shown in FIG. 5, the semiconductor chip S shown in FIG. 4B and the wiring board 10 on which the semiconductor chip S is mounted are substantially flush with each other on the convex curved surface 812 of the lower mold 81 of the molding die 80. The semiconductor element S and the wiring board 10 which are arranged so as to be formed, fixed by the temporary fixing tape 20 and wire-bonded are placed, and the upper die 82 and the concave curved surface 822 thereof are convex from above. Both molds are clamped by placing them so as to match the mold curved surface 812 and face each other.

Next, as shown in FIG. 2, after the lower die 81 and the upper die 82 are clamped, a thermosetting molten resin R is injected into the cavity from the runner 824 through the gate 823. The molten resin R covers the wiring substrate 10, one surface of the semiconductor element S and the wire W.

When the molten resin R is cured, the resin package 30A is uniformly molded with a thin thickness so that the mold portion at least within the range of wire bonding covers the bulging portion of the wire W, and the package 30A is extremely thin. The semi-finished thin semiconductor device can be obtained.

Moreover, the package 30A is a molded package in which the warp of the package 30 which is usually caused by the curing shrinkage when the convex curved surface 812 and the concave curved surface 822 cure the thermosetting resin is preformed. Since 30 (or the semiconductor element S and the wiring substrate 10) is molded in a warped state with a warp equivalent to the above-mentioned warpage, the clamp is released from the lower mold 81 and the upper mold 82. Further, the semi-finished thin semiconductor device in the reverse warpage state becomes substantially flat after the temperature of the package 30 returns to room temperature.

Thereafter, the temporary fixing tape peeling step of FIG. 4D,
As shown in FIG. 3, the desired thin semiconductor device 1A having good flatness can be obtained through the processing steps such as the solder ball forming step of FIG. 4E and the singulation step of FIG.

Therefore, as shown in FIG. 3, when the thin semiconductor device 1A is mounted on the mother board 50 on the electronic equipment side, stable mounting with few connection failures can be performed.

[0043]

As described above, according to the present invention,
It is possible to obtain a flat thin semiconductor device having no warp even though the package has an extremely thin thickness.

Therefore, good handling can be performed in the production process, and high productivity can be maintained. Further, since this thin semiconductor device is flat, it can be mounted on the mother board on the electronic device side with high reliability.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing the structure of a mold die for a thin semiconductor device according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a thin mold semiconductor device and a thin mold semiconductor device showing a state where a thin mold semiconductor device is molded using the mold mold shown in FIG.

FIG. 3 is a cross-sectional view of the thin semiconductor device and the mother substrate showing a state in which the thin semiconductor device molded by using the molding die of FIG. 1 is mounted on the mother substrate.

FIG. 4 is a main manufacturing process diagram for explaining a conventional method for manufacturing a thin semiconductor device.

FIG. 5 is a partial cross-sectional view of a molding die used for a resin package of a conventional thin semiconductor device.

FIG. 6 is a partial cross-sectional view showing a state of molding using the molding die shown in FIG.

FIG. 7 is a cross-sectional view showing a state in which a conventional thin semiconductor device is mounted on a mother substrate.

FIG. 8 is a cross-sectional view showing the structure of another conventional molding die.

9 is a cross-sectional view showing a state in which various parts mounted on a printed board are molded using the molding die shown in FIG.

10 is a cross-sectional view of a conventional thin semiconductor device molded by the molding die shown in FIG.

[Explanation of symbols]

10 ... Wiring board, 11 ... Hollow part, 12 ... Circuit wiring, 13
... via holes, 14 ... solder balls, 20 ... temporary fixing tape, 50 ... mother substrate, 80 ... molding die of the present invention,
81 ... Lower mold, 811 ... Cavity, 812 ... Convex curved surface, 82 ... Upper mold, 821 ... Cavity, 822 ... Recessed curved surface, 823 ... Gate, 824 ... Runner, S ... Semiconductor element, W ... Wire, R ... (molten) resin

Continued front page    F-term (reference) 4F202 AA36 AH37 AM35 CA12 CB01                       CB12 CB17 CK12                 4F206 AA36 AH37 AM35 JA02 JB12                       JB17                 5F061 AA01 BA03 CA21 DA06

Claims (3)

[Claims] 1. A semiconductor element and a wiring board on which the semiconductor element is to be mounted are arranged so as to form substantially the same surface, and a resin package is provided on one surface of the wiring board to which the electrodes of the semiconductor element are connected. In the method of molding a formed thin semiconductor device, when the semiconductor element and the wiring board are molded with a thermosetting resin to form a package, curing shrinkage occurs when the molded thermosetting resin is cured. A method for molding a thin semiconductor device, characterized in that the semiconductor chip and the wiring board are resin-molded in a state in which they are warped by an opposite warpage that is the same as the warpage, in consideration of the warpage of the package that occurs. 2. A semiconductor element and a wiring board on which the semiconductor element is to be mounted are arranged between the lower mold and the upper mold so as to form substantially the same surface, and the electrodes of the semiconductor element are arranged. In a mold die for a thin semiconductor device for forming a resin package on one surface of a connected wiring board, a cavity surface of the lower die is formed into a convex curved surface with a predetermined curvature, and the upper die is formed. A thin semiconductor, wherein a cavity surface of the mold faces the entire surface of the convex curved surface at the predetermined depth, and is formed as a concave curved surface with the same curvature as that of the convex curved surface. Mold for equipment. 3. The curvatures of the convex curved surface and the concave curved surface are determined by molding the thermosetting resin when the semiconductor element and the wiring board are molded with a thermosetting resin to form a package. The mold die for a thin semiconductor device according to claim 2, wherein the mold has a curvature capable of being molded with a reverse warp equivalent to that of the package caused by curing shrinkage when cured.