JPH0147896B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold structure for a semiconductor device in which the front and back sides of an IC chip are covered with different types of materials.

As shown in FIG. 1, the mold structure of a semiconductor device after conventional GB (guyang bonding) is such that the active surface 1a and back surface 1b of an IC chip 1 are covered with the same resin 5. This manufacturing method first
B-stage powder or liquid epoxy resin 5 or silicone resin 5 is supplied as a molding agent to the active surface 1a side of the GB-treated IC chip 1, and heated in a belt furnace, hot plate, thermostatic oven, etc. Then, the back side 1b of the IC chip 1 is
It is turned over and covered with the same resin 5 or a fiber layer containing the same resin 5, and after gelling, it is completely cured. However, during molding, such a mold structure is affected by the surface tension of the resin 5 and its flowability becomes non-uniform, so there may be variations in the range in which the resin 5 flows in the planar direction, or variations in the flowability of the resin 5 in the cross-sectional direction. It is extremely difficult to control the variation in thickness. Furthermore, since both sides of the IC chip 1 must be processed twice in the same process, this also leads to an increase in costs. Therefore, in order to improve the molding structure of the prior art described above, a semiconductor device molding structure in which only the active surface 1a is molded, as shown in FIG. 2, was devised. This is especially used when manufacturing watches, cameras, etc. that require high-density packaging and are also extremely thin. This manufacturing method is similar to that of the conventional example, and since only the steps on the active surface 1a side are required, the cost and material cost are halved.
Here, the control of only the active surface 1a side of the molding agent 5 is due to its surface tension, and the IC
It stops at the boundary between the back surface 1b and the side surface of the chip 1. However, in this method, the flow control is dependent on the viscosity and thixotropy of the molding agent 5.
It is very difficult to manage as it depends on temperature etc.
It often happens that the molding agent 5 flows out onto the back surface 1b. Further, the IC chip 5 may be damaged due to curing shrinkage of the molding agent 5 covering the active surface 1a or a difference in stress distribution caused by a difference in coefficient of linear expansion with the IC chip 5.

The present invention eliminates these drawbacks, and its purpose is to mold an IC chip thinly and with high quality.

The gist of the present invention is to provide a mold structure for a semiconductor device that is molded after simultaneously bonding the electrodes of an IC chip and a plurality of inner leads formed on a flexible substrate. an adhesive or a pressure-sensitive adhesive that is used to remain on the back surface of the IC chip in a bonded state and also protrudes from the sides of the IC chip; and an epoxy resin or adhesive that molds the active surface of the IC chip. silicone resin, and the IC chip is covered with two or more kinds of materials.

Hereinafter, the present invention will be explained in detail based on examples. FIG. 3 shows an embodiment of the present invention,
FIG. 2 is a cross-sectional view of a mold structure of a semiconductor device that is molded only from the active side of an IC chip after GB.

The mold structure of the semiconductor device of the present invention shown in FIG. 3 is different from that of the conventional technology shown in FIG.
In addition to the mold structure of a semiconductor device in which only the IC chip is molded, the back side of the IC chip is also molded with a different resin. In particular, this does not mean that the material is supplied separately. That is, in the GB in which an IC chip 1 and a plurality of inner leads 2 formed on a flexible substrate 3 are bonded, the IC chips 1 are supplied by dicing them from a wafer and supplying them one by one. The other method is to attach the wafer to a glass or resin smooth plate using an adhesive 6 or adhesive 6 that loses its effectiveness at high temperatures.
There is a method of gluing the wafer with the adhesive 6 and the smooth plate together and GBing the wafer as it is. teeth
(10 to 20 μm) is used as is. Normally, this is cleaned after GB, but if a wax or adhesive with particularly good moisture resistance and purity is selected, this cleaning step is also unnecessary. The adhesive 6 remains on the back surface 1b of the IC chip and also protrudes from the sides of the IC chip, so that it also serves to prevent the mold resin 5 from flowing toward the back surface 1b. Furthermore, the thickness of the mold resin is
If the conventional technology covers the entire IC chip,
Since it can be made extremely thin, the stress generated due to the difference in linear expansion coefficient from that of the IC chip 1 when the mold resin 5 cures and shrinks is also reduced. It is possible to reduce quality defects that may lead to breakage. In addition, since the back surface 1b is thinly covered with the adhesive 6, even if an external force is applied to the back surface 1b, the IC chip 1 will not be exposed to the adhesive 6.
Since it is protected by, external force is alleviated and there is no direct damage.

The present invention is particularly effective for small mechatronic products such as wristwatches, cameras, and microcassettes, and has excellent effects in terms of design and quality.

All structural changes made without departing from the spirit of the present invention are included in the present invention.

As described above, according to the present invention, the adhesive or adhesive used when bonding the wafer during the manufacturing process of the IC chip is used while remaining on the back surface of the IC chip. The cleaning process that was used to remove the adhesive or adhesive that was performed in At the same time, it also remains protruding in the side direction of the IC chip, so this remaining adhesive or adhesive prevents the epoxy resin or silicone resin from being applied to the back surface of the IC chip when molding the active surface of the IC chip. For example, the injection amount of the epoxy resin or silicone resin is
If the appropriate amount is used to cover the entire chip except the back surface, the mold thickness will not become unnecessarily thick. In addition, compared to conventional techniques in which the entire IC chip is covered by molding from both sides of epoxy resin or silicone resin, it can be made much thinner, so there is no curing shrinkage of the mold resin.
It also has the effect of reducing the influence of the difference in expansion coefficient with the IC chip, and reducing quality defects such as damage to the IC chip due to a large difference in internal stress, for example.

Furthermore, compared to the conventional technology with a one-sided mold structure that covers only the active surface of the IC chip, for example, in the conventional technology with one-sided mold structure, the back side of the IC chip is bare and the entire IC chip is not molded. , since it is easy for water to enter the boundary between the IC chip and the resin, the water resistance is significantly inferior and the IC
This may cause quality defects such as corrosion of the active surface of the chip, and if an external force acts on the back side of the IC chip, that external force will act directly on the IC chip. Although it has the problem of being easily damaged, the mold structure of the semiconductor device of the present invention is suitable for ICs.
Since the entire chip is covered with resin and adhesive, the above-mentioned problems of the prior art can be avoided.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a mold structure of a semiconductor device showing an example of the prior art. FIG. 2 is a sectional view of a mold structure of a semiconductor device showing another example of the prior art. FIG. 3 is a sectional view of a mold structure of a semiconductor device showing an embodiment of the present invention. 1...IC chip, 1a...active surface, 1b...
Back surface, 2...Inner lead, 3...Flexible substrate, 4...Electrode, 5...Mold resin, 6...
...wafer adhesive.

Claims (1)

[Claims] 1. In the mold structure of a semiconductor device in which the electrodes of an IC chip and a plurality of inner leads formed on a flexible substrate are simultaneously bonded and then molded, it is used when bonding a wafer during the manufacturing process of the IC chip. The IC chip remains on the back surface of the IC chip in a state of
The IC chip is covered with two or more types of materials, including an adhesive or adhesive that remains so as to protrude in the side direction of the chip, and an epoxy resin or silicone resin that molds the active surface of the IC chip. A mold structure for a semiconductor device characterized by the following.