JPS59125630A - Manufacture of semiconductor element - Google Patents

Abstract

PURPOSE:To reduce the cracks and exfoliation of passivation films by coating the surface of a semiconductor substrate on the side where there is little passivation film with a first electrode metallic film, coating the surface of the semiconductor substrate on another side with a second electrode metallic film thinner than the first electrode metallic film and removing the metallic films on the passivation films. CONSTITUTION:The insides of grooves 2 are coated with the glass passivation films 3, the first electrode metallic film 5 is evaporated on the surface on the cathode side, and the second electrode metallic film 4 thinner than said metallic film 5 is evaporated on the anode side, and the metallic films 4 on the glass films 3 are removed through photo-etching technique, etc. When the semiconductor element is manufactured by a process of such order, the generation of cracks in the glass films 3 is very few, and the glass films 3 are hardly exfoliated particularly. It is the most desirable that the thickness of the metallic film 5 on the cathode side is particularly made to be 0.7-1.0mum and the thickness of the metallic film 4 on the anode side 0.5-0.7mum.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor device in which the front and back surfaces of a semiconductor substrate are asymmetrically covered with glass passivation films.

In order to protect the surface of the exposed pn junction of a semiconductor device, a passivation film consisting of a silicon oxide film, a phosphorus glass film, a silicon nitride film, a glass film, and a multilayer film formed by stacking these films is provided. There is.

In this case, in order to increase the voltage resistance of semiconductor devices and to use resin encapsulation metals to lower prices, it is necessary to make a thick film using glass whose thermal expansion coefficient is close to that of silicon, or use a silicon oxide film or phosphor that cannot be thickened by itself. Glass films, silicon nitride films, etc. are stacked in appropriate combinations.

When such a passivation film is made into multiple layers, or when it is layered as in the case of a glass film, the center of curvature is created on the passivation film side of the semiconductor substrate due to stress caused by the difference in thermal expansion coefficient between these passivation films and the semiconductor substrate. It is easy to imagine that the sled with .

Immediately after the passivation film is deposited on such a semiconductor substrate, the film thickness must be controlled to a level that will not cause cracks or peeling unless the passivation film is exposed to heat or physical force. It's not that difficult to do.

However, such a semiconductor substrate, 1. Even if there is no crank or the like at this stage, for the substrate with large warpage as described above, a photoresist film is applied to it by photo etching I+'J, etc., for pattern alignment. Even when this semiconductor substrate and photomask plate are stacked together, the mounting plate is pressed down to make it horizontal without warping. The thickness of the film must be such that no cracks appear in the film.

Naturally, there is a need to deposit an electrode metal film on the aforementioned β conductor substrate by steaming, etc., and then process the metal film into a predetermined pattern using the 7-oto-enoting technique, which results in warpage. If the passivation film becomes larger or the photomask is pressed again, the passivation film must be cut thin. Therefore, it is difficult to create a 1:2 multilayer passivation film or a desired 1-7 glass film without causing cracks or peeling during this process.

In particular, it is difficult to make a multilayer film or thick glass film that does not deteriorate even at high withstand voltages of 600 V or more, especially on a semiconductor substrate with a diameter of 76 m, excluding the contamination caused by resin sealing. It is.

It's my soul, and I'm so proud of myself, and I'm wearing 1 gold 4 metal membranes.
,U11,Photoetching technique +-c,,t:su,2 When the metal film on the board II is removed,
・Kuzopation monthly negative.

On this Friday, the stress of J: is suddenly released -L],
(It's also possible for the evening to enter the film.)
There are a lot of jshiv.

For example, FIG. 1 shows a cross section of a diode element which has been subjected to sivation with a glass film. , 7(pshi1
Nocon board 1 (Then, for diffusion from both sides, J: +2
, a high i layer and a nl layer are provided, respectively. 1)
) 1 row from the threat frill (prlj of size 10011m
Concubine I Kuri Goes North - 2 Power; Yuno f 7 RiK, J
:ri formation, its ji112(]U ll1l i
'c, thickness 1.5/zm glass, l [+t2 at 93
wat] 7, Soo LJ'J, Tonoto (but Denshukin X ('=
n') +1 due to 4 and 5 VC.

The electrode metals range from silicon i + lll to moi) - nickel (Ni) - gold (Au).
is chromium (Cr)-2, multi-layer A-based such as Keru gold +1.
';s is used1. /) and its total thickness is 05-20
/J, m.

Conventionally, when manufacturing such diode elements, the second
As shown in Figure (a), the interior of the tube 42 is first covered with a molten glass film 3, and then, as shown in Figure 1b, the inside of the vortex 2 is coated with a molten glass film 3. et al. 1 (second
As shown in Section 1 (C), the metal film on the glass lj〆3? Removed and rubbed using photo-etching technology. Shayakishi,
One of the best at this age! When I≧, cracks and peeling often occur in the glass film as described in tjlJ.

This is thought to be due to the fact that the warp of the semiconductor substrate is considerably thicker than in the case of using only the oxide film.

The present invention L1 In view of these points, it is a smooth/ζ thing, and even in a good product, the warpage of the semiconductor substrate is avoided. f Small f, Jin
It is an object of the present invention to provide a method for manufacturing a semiconductor device with less occurrence of r-1 peeling.

1. Thinner than the electrode metal film of 281 above. This can be achieved by depositing an electrode metal film of /42 and finally removing the second metal film of the base layer.

Hereinafter, one implementation of the present invention (using all +Q diagrams) will be explained.

FIG. 3 (al to (dl) represent an embodiment of the present invention in step 11
As shown in Figure 2, Figure 3 (al.
? Covered with a medium e glass passivation film with XO<4i2,
Next, in step 1y), the first electrode metal film 5 is deposited on the surface of the six-sword side as shown in FIG. 3+b), and then, as shown in FIG.
As shown in FIG.
As shown in d), the metal film 4 on the glass 1 and 3 is removed by photo-etching or the like. 11 like this
(When manufactured by the process of (), the glass film 3 has a crack.

The occurrence of scratches is extremely low, and there is almost no chance of damage to the glass film. Especially the 6 sort “1 rule cvt”
jJE film 5) The thickness i of the metal film 4 is (1, 7-1, Ottm, anode' + 1 (If) is 0.5 to 0.7.
Am is the most important.

Such effects of the present invention are believed to be due to the following reasons.

That is, as shown in FIG.
When the silicon substrate 1 is deposited on the entire surface, depending on the thickness of the silicon substrate, the center of curvature of the warp of the silicon substrate 1 due to the glass film 3 was on the anode side as shown in this figure. However, the radius of curvature becomes larger, or as shown in Fig. 3 (
The center of curvature of the warp moves toward the cathode as indicated by bl.

In any case, the warpage will be less than that shown in Fig. 3 (al).Next, if a second metal film 4 of 0.5-+0.7 μm is deposited on the anode side as shown in Fig. 3 (cl), The center of curvature of the warp moves toward the anode side again, but as shown in Fig. 3,
The warpage is smaller than that of al. Due to the degree of warpage, the entire anode of the mask plate is ill! Even if the silicon substrate and the glass film are pressed against each other, the stress applied to the silicon substrate and the glass film is small, so there are fewer cracks in the glass. not to mention,
Peeling hardly occurs.

Furthermore, even if the metal film on the glass film is removed and the stress is released, there is little warpage of the silicon substrate, resulting in very few cracks.

Furthermore, since the stress caused by the metal film 5 is large and the warpage toward the cathode side is large, even if the metal film 4 is deposited on the anode side, if the center of curvature of the warp is still on the cathode side,
Even if it is pressed against a silicon substrate using a photomask plate,
As a result, the force that the glass film receives is compressive stress, and clutter does not occur. Ta-dashi cathode II! When a metal film 5f is vapor-deposited on I, it is out of the question to make it into a fully shrunk film so thick that cracks and glue enters the glass.

For example, if the thickness of the metal film 5 is set to 2.0 zzm or more, this possibility increases.

In the above explanation, the glass film is deposited on only one main surface of the silicon substrate, but if the glass film is asymmetrical, it may be possible to adhere the glass film to both sides. It is clear that the passivation film may be not only a glass film but also a multilayer film such as an oxide film, a nitride film, or a phosphorus glass film. There is a detailed explanation of the mesa monument structure, but the Brenner type (
The present invention is applicable even if the

As described above, according to the present invention, in a semiconductor substrate whose front and back surfaces are covered with a passivation film in a non-t or J-shaped manner,
A first thick gold film is deposited on the surface of 1f19, which is free of the passivation I, but has a small amount, and then the other one is deposited.
Deposit a second metal film on the surface of the passivation film, which is stronger than the first gold film, and finally remove the thick gold film on the passivation film. Even if a multi-layered or thick glass beak is used to prevent deterioration due to high withstand voltage, these passivation films will not work! The occurrence of peeling can be greatly reduced and the beautiful effect can be obtained.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the diode and triplet board, Figure 2 is a cross-sectional view of the diode element board divided into the conventional manufacturing 1' north process.
FIG. 3 is a sectional view of a diode substrate in the manufacturing process according to the present invention. 1...Silicon substrate, 3...Glass film, 4...Anor spear 1.

Claims (1)

[Claims] A method for manufacturing a semiconductor device in which the front and back surfaces of a semiconductor substrate are covered with asymmetric passivation films, characterized in that a metal film is first deposited, and finally the metal film on the passivation film is removed. Method.