JP2504465B2 - Semiconductor device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a technique effectively applied to a semiconductor device on which a semiconductor pellet is mounted, for example, a technique effectively used for mounting a semiconductor pellet. Is.

[Prior Art] For the die bonding technology for fixing semiconductor pellets to a substrate (lead frame, ceramic package, etc.), see, for example, the electronic material separate volume "VLSI Manufacturing" issued by the Industrial Research Board on November 20, 1985. -Test Equipment Guidebook ", pages 131 to 137. The outline is as follows.

That is, in this technique, for example, a gold (Au) foil is placed as a preform material on a ceramic substrate, semiconductor pellets are placed on the gold foil, and these are heated by a heat block. And Au to form a eutectic to bond the semiconductor pellets.
Also, after depositing aluminum (Al) on a ceramic substrate, place the above gold foil on it and perform the same method as above.
There is also known a technique in which a eutectic of Si, Au and Al is formed and bonded, or a silver paste, an epoxy resin or the like is used as a preform material for bonding.

[Problems to be Solved by the Invention] By the way, according to the conventional die bonding technique as described above, since the bonding layer is formed on the lower side of the semiconductor pellet and the bonding layer fixes the semiconductor pellet, There was such a difficulty.

That is, in the bonding accompanied by heating, thermal stress is generated inside the semiconductor pellet due to the difference in thermal expansion coefficient between the semiconductor pellet and the substrate when the bonding layer is cooled. In that case, in the case of die-bonding a large-sized semiconductor pellet, it is difficult to make the back surface of the semiconductor pellet and the preform material such as gold foil evenly fit. The same applies when solder, epoxy resin, or the like is used as the preform material. As a result, the thermal stress generated inside the semiconductor pellet is likely to be non-uniform, and the semiconductor pellet is cracked. Such a problem occurs not only during die bonding, but also when resin-sealing a semiconductor pellet or when a semiconductor device is actually used.

Therefore, in such a semiconductor device, the cracks cause deterioration of the characteristics of the semiconductor integrated circuit, resulting in deterioration of reliability and yield of the semiconductor device.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a semiconductor device having a structure capable of effectively preventing the occurrence of cracks in a semiconductor pellet.

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

[Means for Solving Problems] An outline of typical ones of inventions disclosed in the present application will be described below.

That is, in a semiconductor device mounted with a semiconductor pellet, a non-adhesive heat dissipation layer is interposed between the semiconductor pellet and the substrate of the mounted semiconductor device, and a side surface of the semiconductor pellet is surrounded to form a bonding layer on the substrate. It is formed, and the side surface of the semiconductor pellet and the substrate are adhered to each other via this bonding layer.

[Operation] According to the above-mentioned means, since the semiconductor pellet is fixed to the substrate by the bonding layer formed around the semiconductor pellet, it is caused by a difference in thermal expansion coefficient between the semiconductor pellet and the substrate. Thus, the residual stress generated inside the semiconductor pellet becomes substantially uniform over the whole thereof, and the crack generation in the semiconductor pellet is suppressed, whereby the above-mentioned object of improving the reliability and yield of the semiconductor device is achieved.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the semiconductor device according to the present invention.

In the figure, reference numeral 1 represents a ceramic substrate, for example, on which a first layer (heat dissipation layer) 2 having high thermal conductivity is formed. The heat dissipation layer 2 is made of, for example, gel-like metal powder, and is formed before the semiconductor pellet 3 is placed on the substrate 1. The heat dissipation layer 2 is non-adhesive, and the semiconductor pellets 3 are placed on the heat dissipation layer 2 so that they are in contact with each other. The semiconductor pellet 3 is formed into the second pellet formed so as to wrap it.
The heat dissipation layer 2 and the substrate 1 are bonded to each other via a drawing (bonding layer) 4. That is, in this semiconductor device, the semiconductor pellets 3 are fixed to the substrate 1 by placing the semiconductor pellets 3 on the heat dissipation layer 2 and then applying, for example, a silver paste so as to wrap the semiconductor pellets 3. .

According to the semiconductor device configured as described above, since the bonding layer 4 is formed around the semiconductor pellet, the bonding layer 4 is formed inside the semiconductor pellet 3 due to an equal difference in thermal expansion coefficient between the semiconductor pellet 3 and the substrate 1. Due to the effect that the thermal stress becomes substantially uniform over the entire area without being partially concentrated and the generation of cracks in the semiconductor pellet 3 is suppressed, the reliability and yield of the semiconductor device can be improved. That is, when the semiconductor pellet 3 is thermally affected,
Since only the tensile load or the compressive load is received as a whole, cracks are less likely to occur in the semiconductor pellet 3, and as a result, the reliability and yield of the semiconductor device can be improved.

Further, in the semiconductor device of the above-described embodiment, since the heat dissipation layer 2 is provided below the semiconductor pellet 3, the semiconductor pellet 3 that generates heat such as a power transistor has the effect of improving the heat dissipation property. Sex is further improved.

2 and 3 show a second embodiment of the semiconductor device according to the present invention.

This semiconductor device has a structure in which a large number of recesses 1a for embedding a semiconductor pellet are provided in a substrate 1, and a heat dissipation layer 2 and a semiconductor pellet 3 are embedded in each recess 1a. Further, in this semiconductor device, the upper surface of the buried semiconductor pellet 3 and the upper surface of the substrate 1 are formed so as to be substantially flush with each other, and the wiring pattern 5 is formed on the upper surfaces by mask transfer or the like. The pellets 3 and 3 are connected to each other. Note that, in FIGS. 2 and 3, the same reference numerals as those in FIG. 1 represent the same constituent members, and thus their duplicated description will be omitted.

According to this embodiment, not only the effect of the first embodiment can be obtained, but also the upper surface of the buried semiconductor pellet 3 and the upper surface of the substrate 1 are formed to be substantially flush with each other. It is possible to easily connect the semiconductor pellets 3, 3.

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. Nor.

For example, as the bonding layer 4, in addition to the silver paste, a general adhesive for semiconductor pellets such as PIQ (manufactured by Hitachi Chemical Co., Ltd.) which is a polyimide adhesive or silicone rubber can be used. Alternatively, the bonding layer 4 may be formed so as to partially cover the outer edge portion of the semiconductor pellet 3.

In the above description, the invention made by the present inventor has been mainly described in the field of application, which is the application field of the semiconductor pellet mounting technique, but it can also be used in the case of mounting a wafer.

[Effects of the Invention] The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.

That is, the semiconductor pellet is fixed to the substrate by the bonding layer formed around the semiconductor pellet, and since the outer edge of the semiconductor pellet and the substrate are bonded via the bonding layer, the thermal expansion coefficient of the semiconductor pellet and the substrate is large. The thermal stress generated inside the semiconductor pellets is made uniform due to the difference between the two, and the generation of cracks in the semiconductor pellets is effectively prevented. As a result, the reliability and yield of the semiconductor device can be improved.

[Brief description of drawings]

1 is a vertical sectional view of a first embodiment of a semiconductor device according to the present invention, FIG. 2 is a vertical sectional view of a second embodiment of a semiconductor device according to the present invention, and FIG. It is a top view of a semiconductor device. 1 ... Substrate, 2 ... Heat dissipation layer, 3 ... Semiconductor pellet, 4
…… Bonding layer.

Claims (1)

(57) [Claims] 1. In a semiconductor device in which a semiconductor pellet is bonded to a substrate by a bonding layer, a non-adhesive heat dissipation layer is interposed between the semiconductor pellet and the substrate, and a side surface of the semiconductor pellet is surrounded to form a substrate on the substrate. A bonding layer is formed on the substrate, and the side surface of the semiconductor pellet and the substrate are bonded via the bonding layer.