JPS59208768A - Semiconductor pellet mounted body - Google Patents

Abstract

PURPOSE:To form the interval between a pellet and a substrate into the prescribed one as well as to improve the heat dissipating property of the titled semiconductor pellet mounted body by a method wherein connecting electrodes are formed on the back side of a semiconductor pellet and on the surface of the insutalled substrate on which the semiconductor pellet will be connected, and when they are connected using connecting solder, an isolated solder wherein controlling solder is inserted is provided on the front and back sides of the substrate located between said electrodes. CONSTITUTION:Connecting electrodes 2 and 5 are formed respectively on the circumferential part on the back side of the semiconductor pellet 1 and on the surface of the insulated substrate opposing to said semiconductor pellet 1, and they are adhered with each other using a connecting solder 3. According to this constitution, a plurality of isolated electrodes 12 and 13 opposing to the back side of the pellet 1 and the upper surface of the substrate 4 are provided between electrodes 2 and 5, and controlling solder 13 is inserted between said electrodes 12 and 13. Subsequently, of the solder 3 and 13, the solder 13 is swelled out into pole shape or hand drum shape and solidified. Through these procedures, the distance between the pellet 1 and the substrate 4 is formed into the prescribed one, and a heat conducting and radiating path is generated by the isolated electrodes 12 and 13, thereby enabling to increase radiation efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a technique for mounting semiconductor pellets, and in particular to a technique effective for mounting and fixing semiconductor pellets face down on an insulating substrate.

[Background Art] Conventionally, semiconductor pellet mounts have been used that are mounted and fixed by a face-down bonding method in which semiconductor pellets are directly connected to electrodes of an insulating substrate by soldering without using wires (JIS terminology). Dictionary,■
Electric Wire, pp. 321-322). As shown in FIGS. 1 and 2, this mounting body is made by positioning the semiconductor pellet 1 on an insulating substrate 4 having an electrode 5 that substantially corresponds to the electrode 2 of the semiconductor pellet 1 using an appropriate positioning means, and then heating it. This is a semiconductor pellet package in which connection solder 3 is formed and fixed by solder reflow at multiple connection points at the same time using an appropriate heating means such as a furnace, a solder bath, etc. This mounting structure has the great advantage that the bonding time hardly changes even if the number of connection points increases.

However, in this package, the semiconductor pellet and the insulating substrate are directly fixed using solder that has a large deformability, but due to the heat generation of the semiconductor pellet and changes in the environmental temperature, heat corresponding to the difference in thermal expansion between the semiconductor pellet and the insulating substrate is generated. Stress is applied directly to the connection part, which tends to cause peeling near the connection interface with the electrode. Therefore, it has the disadvantage that the usage environment and semiconductor pellet size are limited. This drawback is that this mounting unit uses the natural melting and solidification of the solder at the connection part to perform bonding, so the solder shape after connection becomes a spherical shape, and stress concentrates at the connection interface with the electrode in response to external stress. This is because Furthermore, at the interface between the solder and the electrode, reactions, diffusion, and the formation of compounds occur between the atoms that make up the solder and the electrode.
It is often brittle.

Therefore, as a structure that makes the external stress applied to the connection part uniform and makes maximum use of the deformability of the solder, a mounting body in which the shape of the bulb-shaped body is controlled to be columnar or drum-shaped is known.

As such a semiconductor pellet package, the one shown in FIG.
issue).

That is, when the semiconductor pellet 1-1 and the insulating substrate 4 are connected by solder, a sheet-like or paste-like solder 9 is supplied to the isolated electrode 8 provided on the insulating substrate 4, and the semiconductor pellet 1 and the insulating substrate 4 are soldered together. After soldering and connecting the two, the solder 9 on the isolated electrode B is melted to form a spherical body 10,
The semiconductor pellet 1 is not wetted by using the surface tension of the solder spherical pieces 10 (the semiconductor pellet 1 is pushed up to form a columnar or drum-shaped connection, and then the solder is solidified to fix the semiconductor pellet/nod mounted body). Note that 7 is a solder hill formed on the electrode 5 on the insulating substrate 4.

However, in this semiconductor pellet package, since it is necessary to accurately supply sheet-like or paste-like solder 9 onto isolated electrodes 8, there is a problem that the manufacturing process for the insulating substrate becomes large.

[Object of the Invention] The object of the present invention is to solve the above-mentioned problems, to easily control the solder connection shape, to have high connection reliability and high workability, and to suppress the increase in manufacturing steps. The purpose of the present invention is to provide a semiconductor pellet package that can be used.

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

[Summary of the Invention] A brief overview of typical inventions disclosed in this application is as follows.

That is, a control solder hill is formed at the same time as the solder hill is formed on the electrode of the semiconductor pellet, an isolated electrode is formed at the same time as the electrode is formed on the insulating substrate, and the control solder hill is welded to the isolated electrode to form a sphere. The gap between the pellet and the substrate is controlled to be approximately equal to the height of the electrode solder hill using the missing body, and the connection solder is formed into a columnar or drum shape by utilizing the solder's affinity for the electrode, and then the solder is solidified. It is fixed.

[Embodiment] FIG. 4 is a plan view showing an embodiment of a semiconductor pellet package according to the present invention, and FIG. 5 is a sectional view taken along the line V-V in FIG. 4.

In this embodiment, the semiconductor pellet package includes a semiconductor pellet 1, an insulating substrate 4, pellets 1 to 1, and a substrate 4.
A control device formed in a spherical body with a contact portion between the connection band 3 formed between the upper electrodes 2.5 and the isolated electrodes 11.12 on the pellet 1 and the substrate 4 cut out. The semiconductor pellet 1 is mounted and electrically and mechanically connected to the insulating substrate 4 at the connection solder 3 whose connection height and connection shape are controlled by the control solder 13. There is.

Next, this mounted body is shown in FIG. 6 (al, (bl) in order of manufacturing process.
Explain using.

First, on the mounting surface of the semiconductor pellet 1, an appropriate number of isolated electrodes 11 different from the connection electrode 2 are formed so as to be electrically isolated at appropriate positions inside the connection electrode 2. On this isolated electrode 11, a solder mound 14 for forming the control solder 13 is formed simultaneously with the formation process for the solder mound 6 of the connection electrode 2. For example, solder is simultaneously placed on the connection electrode 2 and the isolated electrode 11 by means such as vapor deposition or plating, and then by means of suitable heating means.
When the dirty solder is melted, the connection electrode 2 and the isolated electrode 1
1, connection solder mounds 6 and control solder mounds 14 are formed simultaneously.

The volume of the control solder mound 140 is equal to H shown in FIG. 6(a), if the height of the electrode in the shape of a ball-shaped one end formed by welding to the isolated electrode 11 of the semiconductor pellet 1 is ignored. ) is the height of the electrode solder hill 6 and is equal to h. ) has a predetermined dimension, for example, about 10 μm higher than that of the pellet 1 and the isolated electrode 11. The height is set to be equal to or slightly lower than the height h of the electrode solder mound 6.

On the other hand, on the insulating substrate 4, a counterpart connection electrode 5 is placed at a position corresponding to the connection electrode 2 of the semiconductor pellet (2), and
Isolated electrodes 12 are formed at positions corresponding to the control solder mounds 14 of the semiconductor pellet 1, respectively. The isolated electrode 12 is formed to have a size equal to or larger than the isolated electrode 11, and can be easily formed, for example, by printing a conductive material on the substrate 4.

The semiconductor pellet 1 and the insulating substrate 4 according to the above structure are
By appropriate means, as shown in FIG.
4 are aligned with the isolated electrodes 12 and temporarily fixed by solder mounds and fluff (not shown) applied to the electrodes 6 and 5 and 14 and 12.

In this temporarily fixed state, the composite of the semiconductor pellet 1 and the insulating substrate 4 is heated by a suitable heating means such as a heating furnace or a molten solder bath.

By this heating, the control solder mounds 14 are melted and adhered and diffused to the solder-compatible isolated electrodes 12 on the insulating substrate 4, resulting in a ball-like shape with both ends cut out, as shown in FIG. 6(b). Then, the control solder 13 is formed. The height of the solder 13 for controlling the solder is maintained at a value set to be approximately equal to the height h of the connecting solder mound 6 by the surface tension of the molten bulb itself.

When the control solder 13, which has a spherical shape with both ends cut out, is formed, the relative height between the semiconductor pellet 1 and the insulating substrate 4 becomes low (as shown in FIG. 6
The tip of the electrode slightly contacts the other electrode 5 of the substrate 4. Since this electrode solder mound 6 is already in a molten state, when it comes into contact with the electrode 5, it spreads over the entire electrode surface and connects the electrodes 2.5, forming the connecting solder 3 as shown in FIG. Fifth
As is clear from the comparison between the figure and FIG. need to fill the space.

By filling this space, the height of the connecting solder 3 tends to be lower than the height of the solder mound 6 in the abutted state with the electrode 5. Furthermore, since the integrally melted solder 3 tends to become spherical due to its surface tension, its height tends to become even lower.

However, as described above, since the control solder 13 tries to maintain a constant height, a predetermined distance is maintained between the semiconductor pellet 1 and the insulating substrate 4, and as a result, the connecting solder 3 is kept at that height. is prevented from lowering. Therefore, the connection height and connection shape of the connection solder 3 are controlled by the control solder 13, and the connection solder 3 is formed into a columnar or drum shape.

In this way, a packaged body is obtained in which the semiconductor pellets are electrically and mechanically mounted and fixed on the insulating substrate using the connection solder which is controlled to have a columnar or drum shape.

[Effects] (1) By forming a control solder hill on the semiconductor pellet that melts to lower the height and maintain a constant height, the control solder increases the pellet when the connecting solder hill is melted and integrated. Since the distance between the insulating substrate and the insulating substrate can be maintained at a desired value, a columnar or drum-shaped connection solder can be obtained.

(2) By providing the control solder hill on the semiconductor pellet, this solder hill can be formed simultaneously with the electrode solder hill provided on the semiconductor pellet, so a dedicated process for forming the control solder ratio is unnecessary. Therefore, it is possible to suppress the increase in the number of steps.

(3) Since the control solder comes into contact with the insulating substrate and forms a thermally conductive radiation path, the heat radiation performance of the semiconductor pellet 1- is improved.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, solder may be formed on connection electrodes and isolated electrodes of an insulating substrate.

[Brief explanation of the drawing]

Figure 1 is a plan view of the connection part of a semiconductor pellet package connected by the conventional face-down bonding method, Figure 2 is a cross-sectional view taken along the line ■ to ■ in Figure 1, and Figure 3 (a).
, (bl, and (c) are cross-sectional views illustrating the manufacturing process of a semiconductor pellet package in which an insulating substrate is provided with a separator solder that does not wet the semiconductor pellet in the conventional face-down bonding method, and FIG. 4 is a cross-sectional view of the present invention. FIG. 5 is a cross-sectional view taken along the line V-V in FIG. 4, and FIG.
, fbl are cross-sectional views illustrating the manufacturing process. 1... Semiconductor pellet, 2... Connection electrode, 3...
Connection bander, 4... Insulating substrate, 5... Connection electrode, 6
...Solder hill, 11.12...Isolated electrode, 13...
- Control solder, 14... Control solder hill. Figure 1 Figure 3 Tokyu → Gu (b) (C)

Claims (1)

[Claims] (2) comprising a semiconductor pellet having a main electrode solder hill, and an insulating substrate having an electrode substantially aligned with the solder hill;
In a semiconductor pellet mounted body in which both are connected and mounted via a connecting solder in which the solder mounds are melted between electrodes, control solder mounds are provided at positions other than the solder mounds of the semiconductor pellets 1-, and , an isolated electrode is provided on the insulating substrate at a position facing the control solder hill, and when the electrode solder hill is melted, the control solder hill is welded to the isolated electrode, and a molten spherical body forms a semiconductor pellet. In order to control the distance from the insulating substrate, the volume of the control solder mound is such that the height before melting is higher than the height of the electrode solder mound, and the height of the spherical body after melting is the same as that of the 1111 electrode. A semiconductor pellet assembly characterized in that the height is set to be approximately equal to the height of a solder hill.