JPH06216167A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] Providing a highly reliable semiconductor device that can reduce variations in reliability without sacrificing other performance by making the thickness of the members uniform. To do. [Structure] In a semiconductor device in which an electrode-treated insulating substrate 4b is arranged on a metal base 2, semiconductor elements 1 are laminated thereon, and each is adhered by a member 5, in a member. A semiconductor device which is a filler containing 30% or less of fine particles 8 having a particle size smaller than the filler thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly reliable semiconductor device and a method of manufacturing the same.

[0002]

_2. Description of the Related Art Taking a power module as an example, a conventional insulating plate made of Al ₂ O ₃ , BeO or the like, or recently made of AlN or the like is connected to a nickel-plated base by soldering. . However, the module is expanding in the direction of a large capacity, and therefore the insulating substrate and the metal base are also becoming large in size, and it is becoming difficult to uniformly connect the members by the members of the members, the air bubbles and the like.

Further, it is being adopted for applications requiring higher reliability, and a connection technique using a uniform bar is important.

On the other hand, as shown in FIG. 2, a structure for securing the flow material 6 of the connecting portion is provided by providing a flow stopper 6 for the flow material around the predetermined attaching portion, and insulation as shown in FIG. A thin intermediate metal plate 7 having irregularities is inserted between the plate 4 and the metal base 2 so that the thickness of the bar members 5a and 5b is uniform.

However, in the structure shown in FIG. 2, the inclination in the plane of the bar cannot be controlled, and for example, the insulating plate 4 and the metal base 2 having different thermal expansion coefficients due to the temperature change caused by the operation and rest of the semiconductor device. The bar 5 between them undergoes fatigue, causing cracking from the thin part of the bar and in extreme cases leading to peeling. There is a relationship as shown in FIG. 4 between the thickness of the filler and the number of cycles of temperature change until crack initiation, and the uniformity of the filler is important for reducing variations in reliability.

Further, in the structure as shown in FIG. 3, heat generated when the semiconductor element operates is radiated from the metal base 2 through the insulating plate 4, but its thermal resistance increases due to the additional member. However, the cooling performance for the element deteriorates.

The heat generation density during the operation of the element tends to increase with the improvement of the element performance, and the deterioration of the cooling performance is a detriment to the performance of the element.

[0008]

As described above, this is achieved by sacrificing a part of the structure and the structure for ensuring the reliability against the size increase of the device.

The present invention is to provide a structure for ensuring reliability corresponding to an increase in the size of a device without sacrificing other performances.

[0010]

[Means for Solving the Problems] This is a proposal of a structure in which the thickness of the bar members is made uniform by paying attention to the relationship of FIG.

[0011]

By making the thickness of the filler uniform, it is possible to reduce the variation in reliability without sacrificing other performances and to provide a highly reliable semiconductor device.

[0012]

FIG. 1 shows an embodiment of the present invention.

The insulating substrate 4b is made of AlN having good thermal conductivity.
And the electrode treatments 4a and 4c have a structure in which thin Cu plates are connected by bonding, and the semiconductor element has a melting point of 300 ° C.
Cu electrode 4a of AlN using about Pb-Sn solder
Soldered on. The thermal expansion coefficients of Si and AlN4b, which are the bases of the semiconductor element 1, are 3 × 10 ⁻⁶ /
Since it is very close to ℃ and 4 × 10 ^-6 ℃, fatigue of the bark is unlikely to occur.

Wiring is performed by the Al wire 3, and C
The u base 2 is bonded with the solder 5 having a melting point of about 180 ° C.
The thermal expansion coefficient of the Cu base is about 17 × 10 ⁻⁶ / ° C., which is large relative to Si and AlN, and the thermal fatigue resistance of this portion is important for ensuring the reliability of the semiconductor device.

Here, in order to secure the desired thermal fatigue life, it is necessary to uniformly satisfy the solder thickness after gluing to 100 μm or more.

Therefore, as the solder for bonding between the Cu base 2 and the AlN substrate 4, Ni that can maintain the grain size even at high temperature is used.
PbSn containing 5% of 70 to 100 μm of fine particles 8
Eutectic solder, thickness 300μm, size is 1/3 of the bonded area
The solder sheet is placed, and a sufficient load is applied from the side of the AlN substrate or the Cu base when the soldering is performed.

As a manufacturing problem, Ni fine particles are
When it is more than 00 μm, the content of Ni fine particles is 30
If it is more than 100%, particles may overlap each other when a load is not applied at the time of squeezing, the gap between the Cu base and the AlN substrate becomes wide, and the amount of solder becomes insufficient, which causes a solder void.

The Ni fine particles 8 shown in FIG. 1 are obtained by uniformly filling the solder sheet with Ni fine particles by rolling.

FIG. 5 shows another embodiment. This figure shows a method of manufacturing with a minimum amount of Ni fine particles embedded to make the thickness of the solder 5 between the Cu base 2 and the AlN substrate 4 uniform. As a result, the PbSn eutectic cream solder 9 is printed on the Cu base 2 and the Ni fine particles 8 are sprinkled on both end portions on the PbSn eutectic cream solder 9, so that the solder thickness can be secured by a local spacer effect. In this case, when the solder melts during soldering and the solder flows out, Ni fine particles are
Since there is a risk of flow out from between the base and the AlN substrate, it is necessary to take measures such as preventing solder flow, reducing solder size, and expanding Ni fine particle dispersion area.

FIG. 6 shows a Cu base 2 as another embodiment.
A case where glass fiber is embedded in the solder 5 between the AlN substrate 4 and the AlN substrate 4 is shown. As for the solder 5, a uniform thickness of the solder can be secured by rolling and embedding at least two glass fibers 10.

[0021]

As described above, it is possible to provide a manufacturing method in which the reliability of thermal fatigue of a large-sized semiconductor device having an insulating plate due to temperature change is improved.

[Brief description of drawings]

FIG. 1 is a plan view and a sectional view of an embodiment of the present invention (a resin layer, wiring, and terminals are omitted).

2A and 2B are a plan view and a cross-sectional view of a conventional structure (electrode treatment of an insulating plate, a semiconductor element, a resin layer and wiring, and terminals are omitted).

FIG. 3 is another conventional example (electrode treatment of insulating plate, semiconductor element,
It is a side view of a resin layer, wiring, and a terminal).

FIG. 4 is a relationship diagram of a solder crack length and a temperature change cycle number (logarithmic display).

5A and 5B are a plan view and a sectional view of another embodiment of the present invention (electrode treatment of an insulating plate, semiconductor elements, resin layers and wirings, and terminals are omitted).

6A and 6B are a plan view and a cross-sectional view of another embodiment of the present invention (electrode treatment of insulating plate, semiconductor element, resin layer and wiring, terminals are omitted).

[Explanation of symbols]

1 ... Semiconductor element, 2 ... Metal base, 3 ... Aluminum wire,
4a ... upper electrode, 4b ... insulating substrate, 4c ... lower electrode, 5
... solder (soldering), 6 ... flow-stopping resin, 7 ... intermediate metal plate,
8 ... Ni fine particles, 9 ... Cream solder, 10 ... Glass fiber.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshiki Kurosu 3-1-1, Saiwaicho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi factory

Claims (9)

[Claims] 1. A semiconductor device in which an electrode-treated insulating substrate is disposed on a metal base, semiconductor elements are stacked on the insulating substrate, and each is adhered by a rod, and the rod is placed in the rod. A semiconductor device, which is a filler containing 30% or less of fine particles having a particle diameter smaller than the thickness. 2. A semiconductor device according to claim 1, wherein fine particles in the filler are locally concentrated. 3. The member according to claim 1, wherein the laminated members are made thicker before being attached than after being attached. 4. The method according to claim 1, wherein the members are printed with a cream-like filler, and then fine particles are inserted onto the filler and each member is stacked in a laminated form and attached. Manufacturing method of semiconductor device. 5. The rod material according to claim 1, wherein the material of the fine particles is a metal / glass / carbon / organic material capable of substantially maintaining the particle diameter above the melting point of the filler. 6. The composition according to claim 1, wherein the component of the timber is lead (P
b) Lead material is 95% or less in the case of solder based on solder, and bell is 95% or less in the case of solder based on Sn (Sn) solder. 7. The fine particles according to claim 1, wherein the shape of the fine particles is fibrous. 8. The bark of claim 1, wherein the bark is in a solid or creamy state. 9. The fine particles according to claim 1, wherein adhesive tabs are laminated between the insulating substrate and the metal base, and between the insulating substrate and the semiconductor element, and a load is applied to the adhesive tabs so that fine particles are formed. A method for manufacturing a semiconductor device, which is capable of ensuring a thickness of a filler substantially equal to a diameter.