JPH11102944A - Manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a small semiconductor device having high reliability at low cost wherein such wiring film as insulating resin film, etc., is used instead of a wiring board made of a copper clad laminated board. SOLUTION: On one surface of an insulating resin film 12 where a transportation hole, etc., is provided, such wirings as inner lead 17, etc., are formed, and after that, boring of a via hole is executed. Further, a cut line 15 for separation is formed along a profile line of a resin sealing layer. Then, a wiring film wherein wirings are formed and a hole is opened in this manner is temporarily fixed to an auxiliary board 21 where a punching return part 22 is formed, then a semiconductor element 24 is mounted and the mounted part is coated and sealed up with an insulating resin. Then, the punching return part 22 of the auxiliary board 21 is removed, a solder ball is array in lattice on a rear surface of an exposed wiring film, and a reflow generates a bump 24. Then, utilizing the cut line 15, a resin-sealed semiconductor device is cut out.

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, and more particularly to a semiconductor device using a wiring film of an insulating resin film or a glass cloth-resin impregnated film and suitable for portable equipment such as a video camera. The present invention relates to a method for manufacturing a device.

[0002]

2. Description of the Related Art In general, a semiconductor device in a semiconductor device is classified into a hermetic seal using ceramics or metal, and a resin seal (resin mold seal).
Compared with the former hermetic sealing with ceramics, the latter resin sealing is slightly less reliable, but is superior in mass productivity and economic efficiency, and has a very high occupancy rate of semiconductor elements. Has merits.

Conventionally, as one of the resin-sealed semiconductor devices, a semiconductor element is mounted on a lead frame made of metal and electrically connected by wire bonding or the like, and a bonding portion between the semiconductor element and a wire is conventionally formed. Is coated and sealed by molding a resin material such as an epoxy resin.

However, in such a semiconductor device, not only is it difficult to mount a plurality of elements, but also there is a problem that an outer lead serving as an external extraction electrode is easily deformed. Therefore, in recent years, using a copper-clad laminate such as a glass-epoxy copper-clad laminate, a wiring group such as an inner lead and a through-hole connection portion for leading these wiring groups to the other side are formed, respectively. The semiconductor element is mounted on the wiring board, and wire bonding is performed.
Semiconductor devices having a resin sealing layer formed by molding have been developed.

In such a semiconductor device, I / O
From the viewpoints of increasing the number of terminals, downsizing of the outer shape, ease of mounting, etc., bumps are formed by arranging balls of solder or the like in a grid (array) as external connection terminals on the rear surface of the wiring board.
A structure called a ball grid array (hereinafter, referred to as BGA) is frequently used. Among such BGAs, particularly, those having a narrow pitch between terminals are FBGAs.
(Fine pitch ball grid array) and its use is expanding.

[0006]

However, the semiconductor device using such a wiring board has the following problems.

That is, in such a wiring board, in order to form a through-hole connecting portion for electrically connecting the wiring groups on both surfaces, holes are drilled one by one at predetermined positions using a small diameter drill. A method of plating the inner wall surface of the hole (through-hole plating) is used, and it takes a lot of time and labor to form the hole, so that it has been difficult to reduce the price of the entire semiconductor device.

In particular, in the case of a BGA type semiconductor device, it is necessary to form through holes equal to or larger than the number of bumps in order to lead to bumps made of solder or the like arranged in a grid.
Therefore, the labor required for drilling holes occupies a large part in the cost structure of the wiring board, which has been a major obstacle to reducing the cost of the semiconductor device.

In recent years, as a semiconductor device which has been made thinner and smaller, a chip size package (CS) having an outer shape formed according to the size of a semiconductor element (chip) has been developed.
P), and among these, a fine pitch area package using an insulating resin film is considered promising.

[0010] Conventionally, such a CSP is manufactured by pasting a copper foil on one or both surfaces of an insulating resin film, forming a wiring pattern or a hole for conduction by a photolithography method, and forming the wiring film on the obtained wiring film. After performing resin sealing by die bonding, wire bonding, transfer molding, etc. of the semiconductor chip, and attaching and forming the solder bumps in order, the film is cut and separated according to the outline of the resin sealing layer. I have.

FIG. 6 shows a position where a cutting line (cut line) for cutting is inserted. In FIG.
Is a wiring film, 2 is an outline of a semiconductor chip, 3 is an outline of a resin sealing layer (transfer mold line), 4 is a cut line, and 5 is a surplus resin flow portion formed at a position of a gate and an air vent during molding. Are respectively shown. The cut line 4 is formed at a position separated from the transfer mold line 3 by L. The length L corresponding to the cutting allowance is determined by the thickness of the wiring film 1, the positional accuracy of the transfer mold line 3 and the cutting accuracy by a tool, and is required to be about 0.3 to 0.5 mm. Further, in order to avoid cutting the excess resin flow portion 5, a cut line 4
Is set.

As described above, in the conventional method of manufacturing a semiconductor device, the cut line 4 is provided at a position 0.5 to 0.7 mm outside the transfer mold line 3 in the CSP that requires further miniaturization. There is a problem that the thickness is 1.0 to 1.4 mm larger than that of the resin sealing layer.

In the final step, the film is cut over the entire circumference of the resin sealing layer, and it is difficult to use a special tool such as a carbide tool. , The management of tools became complicated. Furthermore, cutting defects are likely to occur, which has been one of the causes of difficulty in reducing costs.

The present invention has been made to solve such a problem. Instead of using a wiring board made of a copper-clad laminate, an insulating resin film or a glass cloth-resin impregnated wiring film is used. It is an object of the present invention to provide a method for manufacturing a small and highly reliable semiconductor device at a low cost.

[0015]

According to a method of manufacturing a semiconductor device of the present invention, a required wiring group is formed on at least one principal surface of an insulating resin film, and a hole for conducting is formed. A step of mounting a semiconductor element at a predetermined position on the one main surface of the wiring film on which the group is formed and perforated; A step of arranging and temporarily fixing the semiconductor element on a board, a step of covering and mounting the mounting portion of the semiconductor element with an insulating resin, and a step of forming the auxiliary from the resin sealing body on which the sealing layer of the insulating resin is formed. Removing a part of the board, forming an external connection terminal on the other main surface of the wiring film exposed by removing the auxiliary plate, and connecting the external connection terminal to a wiring on the opposite main surface side via a via hole. Before connecting to the group The resin sealing body on which the external connection terminals are formed, characterized in that a step of cutting along the outline of the resin sealing layer.

According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor device, wherein a required wiring group is formed on at least one principal surface of a glass cloth-resin impregnated film, holes for conduction are formed, and a predetermined position is formed. Forming a cutting line or slit for separation into, at a predetermined position on the one main surface of the wiring film in which the wiring group is formed and perforated,
A step of mounting the semiconductor element; a step of covering and sealing the mounting portion of the semiconductor element with an insulating resin; and a step of mounting the semiconductor element with a sealing layer formed of the insulating resin. Forming an external connection terminal on the main surface, connecting the external connection terminal to a wiring group on the opposite main surface side via a via hole, and sealing the resin sealing body on which the external connection terminal is formed, And cutting using the cut lines or slits formed along the outline of the stop layer.

In the first invention of the present invention, examples of the insulating resin film include a liquid crystal polymer film such as polyparaphenylene terephthalamide, a polyethylene film, a polyimide resin film, and an epoxy resin film. The thickness depends on the type, shape, size, etc. of the semiconductor device to be manufactured.
It is preferably about 100 μm.

Further, in the second invention, as the glass cloth-resin impregnated film, one or more prepregs obtained by impregnating an insulating resin such as an epoxy resin into a glass cloth woven from glass fibers are preferably used. A thin film formed by laminating and molding according to the requirements is 0.05 to 0.15 mm (50 to
A thickness of 150 μm) is used.

In the first and second aspects of the present invention, these insulating resin films or glass cloths are used.
A wiring group such as a signal line and an inner lead group is formed on at least one main surface of the resin-impregnated film, and a conduction hole (via hole) for leading these wiring groups to another main surface is formed. Here, the pitch and arrangement of the inner lead group are set in accordance with the pitch and arrangement of the electrode terminals of the semiconductor element to be mounted. A wiring group including such an inner lead group is formed by vapor deposition patterning on an insulating resin film or a glass cloth-resin impregnated film surface, or a conductive metal such as a copper foil provided on one or both surfaces of these films. It is formed by photo-patterning a layer.

In the present invention, a plurality of conductive holes can be formed simultaneously and in a short time by an etching method or the like in an insulating resin film such as a liquid crystal polymer film, and the processing is performed at very low cost. be able to. Further, in the case of a glass cloth-resin impregnated film, a hole is formed in a conduction hole using a drill or the like, but since a plurality of sheets can be formed and drilled, compared with a conventionally used wiring board, The efficiency of drilling work is high.

Further, such an insulating resin film or a glass cloth-resin impregnated film is formed in accordance with the outer dimensions of a semiconductor device to be manufactured, that is, the outer shape of a resin sealing layer molded in a later step. In addition, a cutting line or slit for separation can be formed in advance. In particular, in the case of a glass cloth-resin impregnated film, it is preferable to form a slit having a width of about 0.5 mm from the cut line, since there is no waving of the film after molding. The cutting line can be formed with high dimensional accuracy by, for example, a parting-off method using a knife blade, and a better cut surface can be obtained by using a grooved underlay.

Further, as shown in FIGS. 1 (a) to 1 (c), the shape of the cut line or slit 6 is rectangular according to the outline of the resin sealing layer, and a plurality of short connecting portions 7 remain. It is desirable to have such a shape. In particular, considering the ease of work in the subsequent separation process and the smoothness of the cut end face,
As shown in FIG. 1A, the rectangular vertices at the four corners are
It is most desirable that the shape be left as is. In the drawing, reference numeral 8 denotes an insulating resin film or a glass-resin laminated film, 9 denotes a transport hole, 10 denotes a positioning hole, and 11 denotes an island (bed) portion for mounting a semiconductor element.

In the step of forming wiring groups and forming holes, an insulating resin film or a glass cloth-resin impregnated film 8 is used.
In the case where such cut lines or slits 6 are formed, it is possible to easily separate the inner resin sealing body from the frame around the film only by cutting the connecting portions 7 such as the four corners. it can. Further, in the formation of such cut lines or slits 6, there is almost no need to take a margin (cut-out allowance), so that it is possible to further reduce the size of a semiconductor device such as a CSP.

Further, since the film cutting work in the final step can be performed by cutting only the connecting portion, the process management and the working method are remarkably facilitated, and a precision tool such as a carbide tool can be used for cutting. Therefore, a high yield can be achieved, and a reduction in price can be achieved.

In the first aspect of the present invention, the auxiliary plate may be a thin plate of a metal such as stainless steel or titanium. It is desirable that the thickness be as thin as possible and have sufficient rigidity and toughness, for example, about 0.5 mm for a stainless steel plate. In addition, since such an auxiliary plate is at least partially removed from the wiring film after the completion of the covering / sealing step by the resin mold, the portion should be punched back to facilitate removal. Is desirable. That is, it is desirable that a cutting line is made along the boundary between the part to be removed and the frame part not to be removed, and the inside part is punched out and then fitted again to form a punch-back part, a so-called pushback part.

In the first aspect of the present invention, the wiring film using the insulating resin film is temporarily fixed to a thin auxiliary plate having such rigidity, and then the mounting and mounting of the semiconductor element and the covering with the resin mold are performed. -It is desirable to perform sealing in order. With this configuration, assembly and manufacturing can be performed in the same process as that of a conventional semiconductor device using a lead frame, and there is no need to construct a special process by using an insulating resin film. Further, since the auxiliary plate can be used any number of times after the removed portion is fitted back to the original state, no extra cost is required by using the auxiliary plate.

Further, in the first invention, after the semiconductor element is mounted and mounted on the wiring film, the wiring film on which the semiconductor element is mounted may be temporarily fixed to the auxiliary plate. As described above, even if only the molding step of the resin sealing layer is performed in a state of being backed by the auxiliary plate, the above-described effect can be improved.

In the first invention and the second invention,
As an external connection terminal formed on the other main surface of the wiring film using the insulating resin film or the glass-resin laminated film, for example, there is a ball-shaped bump mainly composed of a Pb / Sn-based solder. They are arranged in a lattice. And the formation of such solder bumps
For example, the bumps formed on the bump alignment plate can be aligned with the other main surface of the wiring film, and heated and pressed to transfer and bond them (transfer bump method).

[0029]

Embodiments of the present invention will be described below with reference to the drawings.

In the first embodiment, a liquid crystal polymer film Vectran (trade name of Kuraray Co., thickness: 70 to 100 μm) is used as an insulating resin film, and copper foil is thermocompression-bonded to one side of the film. After opening a hole for transport and a hole for positioning at predetermined intervals along the length direction, in each semiconductor device forming portion, by a method such as photo-patterning a copper foil,
On one surface, an inner lead group and a wiring group such as a signal line group connected to the inner lead group are formed. In addition, a plurality of holes for leading the wiring groups to the other main surface are simultaneously formed at predetermined positions of the film by photolithography. Further, cut-off lines are formed in accordance with the outline of the resin sealing layer, for example, by cutting off with a knife blade, leaving four corners uncut.

FIG. 2 shows a schematic shape of the wiring film thus obtained. FIG. 3 is an enlarged view (including the wiring pattern) of a part (A part) in FIG. In these figures, reference numeral 12 denotes an insulating resin film (Vectran), 13 denotes a transport hole, 14 denotes a positioning hole, 15 denotes a cutting cut line, 16 denotes an island portion for mounting a semiconductor element, 17 denotes an inner lead, Numeral 18 denotes a temporary fixing portion for temporarily fixing to an auxiliary plate described later. Reference numeral 19 denotes a hole for forming a via hole;
0 indicates a wiring such as a signal line.

Next, a semiconductor device is manufactured using the wiring film as described below. That is, as shown in FIG. 4 showing one section of the wiring film in cross section, this wiring film is placed on a stainless steel sheet having a thickness of about 0.5 mm with the surface on which the wiring 20 such as the inner lead 17 and the signal line is formed upward. And is temporarily fixed at the temporary fixing portion via a solder or a resin-based adhesive or using an adhesive tape (FIG. 4A). The auxiliary plate 21 is provided with a transport hole and a positioning hole at the same position as the wiring film in advance, and a punch-back portion 22 is formed at a predetermined position by a pushback method. That is, in the auxiliary plate 21, a cutting line 23 for pushback is inserted at a position outside the cutting line 15 for separating the wiring film, and the inner punched portion is fitted back (pushback).

Next, as shown in FIG.
In the island portion 16 of the wiring film temporarily fixed to 1,
After the semiconductor element 24 is arranged and fixed (die-bonded) with an insulating adhesive (not shown) such as an epoxy resin, the electrode terminals 24a of the semiconductor element 24 and the inner leads 17 of the wiring film are respectively connected to each other. The connection is made using a bonding wire 25 such as a gold wire. Then, FIG.
As shown in (c), a resin sealing layer 26 that covers and seals the semiconductor element 24, the bonding wires 25, and their joints is formed by transfer molding of epoxy resin or the like. Next, as shown in FIG. 4D, after the punch-back portion 22 of the auxiliary plate 21 is removed, FIG.
As shown in (2), solder bumps 27 arranged in a grid are formed on the exposed back surface of the wiring film. That is,
After mounting the Pb / Sn-based solder ball so as to be embedded in the hole 19 provided in the wiring film, reflow is performed to form the solder bump 27 connected to the wiring 20 on the other surface via the via hole. . Thereafter, the connecting portions at the four corners of the separating cut line 15 formed in advance on the wiring film are cut off, and the inner portion is cut off from the outer frame portion to obtain the semiconductor device shown in FIG.

In the embodiment configured as described above,
Since a wiring film made of a thin insulating resin film is used in place of the conventionally used printed wiring board, a large number of holes for forming via holes can be formed simultaneously and in a short time by photo etching. And inexpensive processing is possible. Specifically, 28mm x 14
When roughly estimated for a BGA substrate of about 3 mm (8p), although there are widths depending on the construction method and wiring rules, a semiconductor device can be provided at a very low price at 5 to 50% of the conventional price.

In the above embodiments, an example using a polyparaphenylene terephthalamide film as a liquid crystal polymer was described. However, the insulating resin film used in the present invention is not limited to this. The same effect can be obtained by using a film made of a resin or an epoxy resin.

Further, only the molding step of the resin sealing layer 26 may be performed in a state where the resin sealing layer 26 is temporarily fixed on the auxiliary plate 21. That is, after performing die bonding and wire bonding of the semiconductor element 24 with the wiring film as it is, the semiconductor element 24 is temporarily fixed to the auxiliary plate 21 and the resin sealing layer 26 is molded while being temporarily fixed on the auxiliary plate 21. Even with this configuration, a sufficient improvement effect can be achieved in terms of improving workability and reducing costs.

Further, in the embodiment, the insulating resin film 1
Although an example in which the single-sided wiring film having the inner leads 17 and the wiring 20 patterns such as signal lines formed on only one side is described above, a double-sided wiring film having a wiring pattern formed on both sides can also be used. That is, a wiring group such as an inner lead group and a signal line is formed on one surface of the insulating resin film, and a pad group for connecting a predetermined wiring group and an external connection terminal is formed on the other surface. Even when a double-sided wiring film having via holes for conducting wiring groups is used, a highly reliable semiconductor device can be obtained at low cost by employing the method of the present invention.

Next, another embodiment of the present invention will be described.

In the second embodiment, the thickness is 0.05 to 0.15
In the same manner as in the first embodiment, a hole for transport and a hole for positioning are respectively formed in a copper-clad film in which copper foil is adhered to one side of a glass cloth-epoxy resin impregnated film having a thickness of mm, and then photo-patterning and the like are performed. By the method described above, a wiring group such as an inner lead and a signal line is formed. Further, a hole is formed by using a drill or the like to lead the wiring group to the other surface.
In addition, according to the outline of the resin sealing layer to be molded in a later step, a separating slit (approximately 0.5 mm in width) is formed by leaving four corners.

Next, the semiconductor element is die-bonded to the island portion of the wiring film thus obtained, and the electrode terminals of the semiconductor element and the inner leads are wire-bonded, and the outside thereof is resin-sealed by epoxy resin transfer molding. Form a layer. Next, on the back surface of the wiring film thus resin-sealed, solder balls are attached in a grid pattern to form bumps.

Thereafter, as shown in FIG. 5, the connecting portions 30 of the separating slits 29 formed in advance in the wiring film 28 are cut obliquely (cut lines).
The semiconductor device is obtained by inserting 31 and separating the inner portion from the outer frame portion. In this drawing, reference numeral 32 denotes an outline of the semiconductor element, 33 denotes an outline of the resin sealing layer (transfer molding line), and 34 denotes an excess resin flow portion formed at the position of the gate and the air vent during molding. ing.

In the second embodiment constructed as described above, holes for forming via holes can be efficiently formed by stacking a large number of holes, and as shown in FIG. By simply cutting the connecting portions 30 remaining at the four corners 29, the resin-sealed semiconductor oil device can be easily cut off. Further, the slit 29 previously formed in the wiring film is used as it is for cutting off, and the slit 29 is formed along a transfer mold line 33 in a later step, and the margin length L from this line is almost reduced. Since it is not necessary to employ the semiconductor device, it is possible to further reduce the size of a semiconductor device such as a CSP.

Further, the formation of the slit 29 and the like at the stage of the wiring film makes it possible to electrically evaluate a short circuit or lack of the wiring group before mounting the semiconductor element, thereby simplifying the inspection process. In addition to contributing to the improvement of the yield.

Further, since the film cutting work in the final step can be performed by cutting only the connection portion, the process management and the working method are remarkably facilitated, and a precision tool such as a carbide tool is used for cutting. As a result, a high yield can be achieved and a price reduction can be achieved. Further, by using a carbide tool or the like, the surplus resin flow portion 34 can be cut at the same time, and a high-quality CSP can be obtained.

[0045]

As is apparent from the above description, according to the first aspect of the present invention, in the production of a wiring film,
Since a large number of via holes can be formed simultaneously and in a short time by photolithography or the like, extremely inexpensive processing is possible, which is effective in reducing the price of semiconductor devices. Also, by temporarily fixing the wiring film based on the insulating resin film to the auxiliary plate and using it, in the same process as that using the conventional lead frame as the base material,
A semiconductor device can be assembled and manufactured, and a highly reliable semiconductor device can be obtained at low cost.

Further, according to the manufacturing method of the second invention,
Separation work in the final step is easy, and there is almost no need to take a margin (separation allowance) from the outline of the resin sealing layer, so that further miniaturization of semiconductor devices such as CSP can be achieved. it can.

[Brief description of the drawings]

FIG. 1 is a plan view showing a shape of a cut line or a slit formed in a film in the present invention.

FIG. 2 is a plan view showing the shape of a wiring film used in the first embodiment of the present invention.

FIG. 3 is an enlarged plan view showing a portion A in FIG. 2;

FIG. 4 is a cross-sectional view for explaining each step of the first embodiment of the present invention.

FIG. 5 is a plan view showing a position where a cutting line for cutting (cutting line) is inserted in the second embodiment of the present invention.

FIG. 6 is a plan view showing a position where a cut line is to be inserted by a conventional method.

[Explanation of symbols]

 12 ... Insulating resin film 13 ... Conveying hole 15 ... Cut-off line 17 ... Inner lead 19 ... Hole for via hole 20 ... Wiring 21 ... Auxiliary plate 22 ... .. Punch-back portion 24 semiconductor element 25 bonding wire 26 resin sealing layer 27 solder bump 28 wiring film 29 slit 31 for cutting 31 cut line 33 ……… Transfer mold line 34 ……… Excess resin flow section

Claims (6)

[Claims] 1. A step of forming a required wiring group on at least one main surface of an insulating resin film and making holes for conduction, and forming the wiring group and forming one of the holes in the wiring film. A step of mounting a semiconductor element at a predetermined position on the main surface; a step of arranging and temporarily fixing a wiring film in which the wiring group is formed and perforated on an auxiliary plate having rigidity; A step of covering and sealing the mounting portion of the insulating resin with an insulating resin, from a resin sealing body on which a sealing layer of the insulating resin is formed,
Removing the part of the auxiliary plate, forming an external connection terminal on the other main surface of the wiring film exposed by removing the auxiliary plate, and connecting the external connection terminal to the opposite main surface side via a via hole A method of manufacturing a semiconductor device, comprising: a step of connecting the wiring group; and a step of cutting out a resin sealing body on which the external connection terminals are formed, along an outline of the resin sealing layer. . 2. A semiconductor device is mounted at a predetermined position on a wiring film temporarily fixed on the auxiliary plate, and then a mounting portion of the semiconductor device is covered with an insulating resin and sealed. The method for manufacturing a semiconductor device according to claim 1. 3. A cutting line or a slit is formed in a predetermined position of the insulating resin film in the step of forming the wiring group.
The manufacturing method of the semiconductor device described in the above. 4. The method according to claim 1, wherein the auxiliary plate has a punch-back portion that has been cut out and fitted and cut back in advance, and the punch-back portion is removed in a step of removing the auxiliary plate. The method for manufacturing a semiconductor device according to claim 1, wherein: 5. A step of forming a required wiring group on at least one main surface of the glass cloth-resin impregnated film, forming a hole for conduction, and forming a cut line or slit for separation at a predetermined position. A step of mounting a semiconductor element at a predetermined position on the one main surface of the wiring film in which the wiring group is formed and perforated; and covering and sealing a mounting portion of the semiconductor element with an insulating resin. And a step of forming an external connection terminal on the other main surface of the wiring film in the resin sealing body on which the sealing layer of the insulating resin is formed, and connecting the external connection terminal to the opposite main surface side via a via hole. And a step of separating the resin sealing body on which the external connection terminals are formed using the cut lines or slits formed along the outline of the resin sealing layer. That The method of manufacturing a semiconductor device according to symptoms. 6. In the step of forming the external connection terminal,
6. The semiconductor device according to claim 1, wherein bumps mainly composed of Pb / Sn-based solder are formed in a grid pattern on the other main surface of the wiring film. Method.