JP3381833B2 - BGA type semiconductor device and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a BGA type semiconductor device, and more particularly to a shape of an elastomer and a method of forming the elastomer.

[0002]

2. Description of the Related Art In recent years, in order to cope with the miniaturization of semiconductor elements and the miniaturization of semiconductor devices accompanying the high performance and multi-functionalization of electronic equipment, solder balls are arranged in an area array on the lower surface side to achieve high density. A semiconductor device called a surface mounted ball grid array (BGA) has been proposed.

As an example of this, US Pat. No. 5,148,265
In No. BGA type, an insulating film having a wiring pattern is arranged on the surface (functional surface side) of a semiconductor chip via an elastomer, and a plurality of solder balls are arranged in a grid on the surface of the insulating film. Semiconductor device (μBG
There is A).

In this semiconductor device (μBGA), a semiconductor chip and an insulating film provided with a wiring pattern are connected via an elastomer in order to relax thermal stress.
Further, the elasticity of the elastomer enhances the contactability with the wiring pattern, and the cushioning effect prevents the occurrence of chip cracks during and after mounting, thereby improving reliability.

Conventionally, as a method of fixing a semiconductor chip and an insulating film, first, an elastomer is formed in a rectangular shape on the surface side of the insulating film by a screen printing method, and the semiconductor chip is directly fixed on this. Alternatively, after the elastomer is printed, it is cured through a heating process, and then the elastomer is printed again on the surface, and the semiconductor chip is fixed onto the elastomer.

[0006]

However, when the semiconductor chip is fixed on the uncured elastomer printed as described above, as shown in FIG. 15, the mechanical pressure at the time of fixing and the self-weight of the semiconductor chip S are increased. As a result, the elastomer flows out in the width direction from the frame side of the elastomer E, that is, in the vicinity of the middle of the left and right sides of the side forming the outer periphery of the elastomer E, and the leads L positioned on the left and right of the elastomer E and the leads L concerned. It leaks to the back surface side of the insulating film F from between and adheres to the solder ball mounting portion (not shown).

If the elastomer adheres to the leads, it hinders the movement of the leads when they are cut during lead bonding, causing misbonding. Further, if the elastomer leaks to the back surface side of the insulating film and adheres to the solder ball mounting portion, there is a problem that the solder ball is not fixed in the solder ball melting step, which significantly reduces the productivity of the semiconductor device. There is.

The present invention has been made in view of the above circumstances, and provides a BGA type semiconductor device and a method of manufacturing the same, which contributes to prevention of adverse effects due to the outflow of an elastomer when an insulating film and a semiconductor chip are fixed to each other. To aim.

[0009]

In order to achieve the above object, the present invention according to claim 1 comprises a semiconductor chip having a plurality of bonding pads on its peripheral portion and a wiring pattern, and is connected to the wiring pattern and protrudes. And an insulating film comprising a plurality of solder balls for electrical connection to the outside, and while sticking the functional surface side of the semiconductor chip via the elastomer formed on the wiring pattern surface, In a BGA type semiconductor device in which leads extending from the wiring pattern are connected to the plurality of bonding pads, and a connecting portion between the semiconductor chip and the leads is covered with a coating material, the elastomer is
It is characterized in that the frame side is formed to have a recess.

According to a second aspect of the present invention, a semiconductor chip having a plurality of bonding pads on its peripheral portion and a wiring pattern are provided, and the semiconductor chip is connected to the wiring pattern and protrudes to electrically connect to the outside. An insulating film comprising a plurality of solder balls, the functional surface side of the semiconductor chip is attached via an elastomer formed on the surface of the wiring pattern, and the wiring pattern is formed on the plurality of bonding pads. In the method of manufacturing a BGA type semiconductor device in which more extending leads are connected and the connecting portion between the semiconductor chip and the lead is covered with a coating material, the step of providing the elastomer includes forming a protrusion on a part of a frame side. Prepare a metal mask having a plurality of openings, and position the metal mask on the insulating film. Characterized in that it comprises a elastomeric forming step of filling the elastomer in the opening, and removing the metal mask.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The same parts are designated by the same reference numerals and the description thereof will be omitted.

FIG. 1 shows a BGA type semiconductor device of the present invention. A method of manufacturing the semiconductor device will be described with reference to FIGS. 4 to 13. First, as shown in FIG. 4, a copper foil 2 is attached to the surface of an insulating film 1 made of a polyimide tape, a photoresist (not shown) is further applied to this surface, and patterning is performed by photolithography. Then, the pattern of the copper foil 2 is formed.

Thereafter, a photoresist is further applied,
Photolithography is performed to form a resist pattern R as shown in FIG. Although only half of one semiconductor device to be manufactured is shown in the following drawings, a plurality of semiconductor devices are formed at a predetermined interval so that a plurality of semiconductor devices are manufactured at the same time.

After forming the state shown in FIG. 5, gold plating 3 is formed on the surface of the copper foil 2 exposed from the resist pattern R by electroless plating as shown in FIG.

Then, a photoresist is applied from the back surface side, and photolithography is performed to form a resist pattern. The insulating film 1 is etched using this as a mask. As shown in FIG. A window W is formed in the peripheral region formed and a via V is formed in the region where solder balls are formed.

Then, as shown in FIG. 8, the solder balls 4 are formed so as to be connected to the pattern of the copper foil 2 and project to the surface in the via V excluding the lead forming portion.

Then, as shown in FIG. 9, copper etching is performed to remove the copper exposed in the window W by etching. As a result, only the gold pattern as the lead 3S exists in the window W, which is in a flexible state. And in the central part, the pattern of copper foil 2 and gold plating 3
And a two-layer structure, which are respectively connected to the leads 3S, and function as a wiring pattern.

Then, on the side of the wiring pattern forming surface of the insulating film shown in FIG. 9, as shown concretely in FIG. 14, a plurality of openings O in which substantially triangular protrusions T are formed on a part of the frame side. The metal mask M having the above is placed, and while the upper surface of the metal mask is slid with a squeegee SK, the opening 5 is filled with the elastomer 5, the metal mask is removed, and the elastomer is cured through a predetermined heating step. Let In this embodiment, the final elastomer thickness is 110 μm, and the thickness of the cured elastomer is 80 μm. FIG. 10 is a cross-sectional view showing a state in which the elastomer 5 is formed on the wiring pattern formation surface side of the insulating film shown in FIG.

As a method of forming an elastomer on the insulating film, there is also a method of attaching an elastomer formed in a predetermined shape on the insulating film with an adhesive or the like.

Elastomer 5 formed as described above
As shown in FIGS. 2 (a) and 2 (b), in consideration of the flow-out of the elastomer in the width direction, the left and right sides of the frame are formed to have a recess. The amount of depression at this time is about 0.3 mm at the maximum from the position where there is no depression on the left and right sides.

After that, a metal mask similar to the above is placed on the surface of the elastomer 5 and an adhesive is applied with a thickness of 30 μm, and as shown in FIG. 11, the insulating material having the elastomer 5 with a thickness of 110 μm is formed. The film is positioned on the diced semiconductor chip 6 and fixed to the element forming surface side of the semiconductor chip.

Then, as shown in FIG. 12, by using the bonding tool BT, the leads 3S are thermocompression-bonded to the bonding pads on the peripheral portion of the semiconductor chip 6, thereby electrically connecting the wiring pattern to the semiconductor chip. Make a connection. At this time, since the lead 3S is thin, it is cut at the same time as thermocompression bonding.

Then, as shown in FIG. 13, there is prepared a frame body P having a plurality of openings having opening areas and heights equivalent to those of the semiconductor device chip, corresponding to the existing positions of the semiconductor chips. Then, the insulating film connected to the semiconductor chip is fixed to the frame P so that the semiconductor chips are arranged in the openings, and the insulating coating agent is applied in the window W by using potting. By filling with 7, the bonding pad portion of the semiconductor chip 6 and the connecting portion of the lead are covered.

In the above coating, if the coating agent is filled while vacuum suction is performed, the coating agent can be satisfactorily filled.

After that, the elastomer and the insulating film are cut using a punching device, and the BGA type semiconductor device which is individually divided as shown in FIG. 1 is completed.

In the above embodiment, the semiconductor chip is bonded to the insulating film on which the solder balls are formed, but the solder balls may be formed after the bonding and coating are completed. Less than,
The manufacturing method in this case will be briefly described.

First, the state shown in FIG. 7 is formed by the method described above, the via V is covered and protected by a resist or the like, and the copper foil 2 is etched. After that, an elastomer is formed on the surface of the insulating film on which the wiring pattern is formed by a screen printing method or by pasting, and an adhesive is applied to the surface of the elastomer to fix it to the semiconductor chip.

After that, the semiconductor chips are electrically connected to each other, the electric connection portions are coated, the resist formed in the vias is removed, and holes are formed in the solder ball forming regions.

Then, a flux is applied to the copper foil exposed in the hole, and a solder ball having a diameter of 0.7 mm and made of Pb 10% and Sn 90% solder is supplied to the copper foil at 320 ° C.
The solder ball is fixed to the copper foil pattern through a heating process for 0 seconds (peak temperature maintaining time). Then, if necessary, it is immersed in isopropyl alcohol (IPA) for ultrasonic cleaning to remove excess flux. Finally, if necessary, the surface of the solder ball is plated with a noble metal such as palladium, and then a punching device is used to obtain individual semiconductor devices.

Here, the solder balls are formed in a lattice shape, and the back surface of the semiconductor chip is in a bare state. In this way, a highly reliable semiconductor device is formed.

In the embodiment described above, the pitch of vias and the hole diameter can be changed as appropriate. For example, if the grid pitch is 1 mm, the hole diameter is 0.55 m.
m, and the grid pitch is 1.5 mm, the hole diameter is 0.75
It can be mm.

Further, the composition of the solder balls can be changed as appropriate. For example, if the solder balls are Pb 37%, Sn
It is made of 63% eutectic solder, and the heating temperature in the fixing process is 2
It is also possible to set the temperature to about 30 ° C.

Instead of the adhesive applied to the surface of the elastomer 5, the elastomer may be applied again and this may be used as the adhesive, or the elastomer 5 may be formed thicker and the elastomer may be formed thicker. The semiconductor chip may be directly adhered to the surface of, and the heating step is not always necessary.

The amount of depression of the elastomer can be appropriately changed depending on the conditions such as the thickness and viscosity of the elastomer.

When the elastomer is subjected to a heating process, the elastomer as the first layer is formed into a rectangular shape and used as a pedestal, and the elastomer as the second layer for fixing the semiconductor chip or the frame side of the adhesive is recessed. You may form so that it may have.

Further, in the embodiments (a) and (b) of FIG. 2, the elastomer is considered to flow out only in the width direction,
Although it is formed so as to have dents on the left and right frame sides, when the elastomer is not cured by heating, that is, when the semiconductor chip is directly fixed to one layer of the elastomer, as shown in FIG. By forming the, it is possible to reliably avoid the influence of the elastomer flowing out.

[0037]

As described above, according to the present invention,
In consideration of the outflow of the elastomer in advance on the frame side of the elastomer, the frame side is formed to have a recess,
When the semiconductor chip is fixed, even if the elastomer flows out in the width direction, it does not adhere to the leads located on the left and right of the elastomer, and it is possible to prevent misbonding during lead bonding.

At the same time, since the elastomer does not flow to the back side of the insulating film and adhere to the solder ball mounting portion, the solder balls can be reliably fixed even in the solder ball melting step.

[Brief description of drawings]

FIG. 1 is a sectional view of a semiconductor device according to the present invention.

FIG. 2 is an enlarged view of an essential part showing a first embodiment of the present invention.

FIG. 3 is an enlarged view of an essential part showing a second embodiment of the present invention.

FIG. 4 is a diagram showing a manufacturing process of a semiconductor device of the present invention.

FIG. 5 is a diagram showing a manufacturing process of a semiconductor device of the present invention.

FIG. 6 is a diagram showing a manufacturing process of a semiconductor device of the present invention.

FIG. 7 is a diagram showing a manufacturing process of a semiconductor device of the present invention.

FIG. 8 is a diagram showing a manufacturing process of a semiconductor device of the present invention.

FIG. 9 is a diagram showing a manufacturing process of a semiconductor device of the present invention.

FIG. 10 is a diagram showing a manufacturing process of a semiconductor device of the present invention.

FIG. 11 is a diagram showing a manufacturing process of a semiconductor device of the present invention.

FIG. 12 is a diagram showing a manufacturing process of a semiconductor device of the present invention.

FIG. 13 is a diagram showing a manufacturing process of a semiconductor device of the present invention.

FIG. 14 is a diagram showing screen printing for forming the elastomer shape of the present invention.

FIG. 15 is a view showing a state in which a semiconductor device chip is mounted on a conventional elastomer shape.

[Explanation of symbols]

1, insulating film 2, copper foil 3, gold plating 3S, lead 4, solder balls 5, elastomer 6, semiconductor chip 7, coating agent

Claims (2)

(57) [Claims] 1. A semiconductor chip having a plurality of bonding pads on a peripheral portion, a wiring pattern, and a plurality of solder balls connected to the wiring pattern and protruding to electrically connect to the outside. Which is made of an insulating film, is attached to the functional surface side of the semiconductor chip via an elastomer formed on the surface of the wiring pattern, and connects the leads extending from the wiring pattern to the plurality of bonding pads. In the BGA type semiconductor device in which a connecting portion between the semiconductor chip and the lead is covered with a coating material, the elastomer is formed so that a frame side has a recess. 2. A semiconductor chip having a plurality of bonding pads on its peripheral portion, a wiring pattern, and a plurality of solder balls connected to the wiring pattern and protruding to electrically connect to the outside. Which is made of an insulating film, is attached to the functional surface side of the semiconductor chip via an elastomer formed on the surface of the wiring pattern, and connects the leads extending from the wiring pattern to the plurality of bonding pads. In the method of manufacturing a BGA type semiconductor device in which a connection portion between the semiconductor chip and the lead is covered with a coating material, the step of providing the elastomer includes a metal having a plurality of openings in which protrusions are formed on a part of a frame side. A mask is prepared, the metal mask is positioned and placed on the insulating film, and an elastomer is placed in the opening. And an elastomer forming process of filling the method of manufacturing a BGA type semiconductor device which comprises a step of removing the metal mask.