JPS587815A - Semiconductor device - Google Patents

Abstract

PURPOSE:To strengthen the mechanical strength of the fringe of a substrate, by thickening the fringe of the semiconductor substrate more than the other part. CONSTITUTION:The N type Si substrate 21 is formed thicker in the fringe on the lower surface thereof than the other part with the upper surface thereof in a negative beveled structure, and a P type region 22, an N<+> type region 23 and an insulator 24 constituted of silicon rubber are formed as illustrated. Thus, the fringe of the Si substrate 21 is strengthened mechanically more than the other part resulting in the restriction of increase of the power loss in the element by making the thickness of the part for an essential current flow the same as the conventional one.

Description

[Detailed description of the invention] The present invention relates to a semiconductor device.

2. Description of the Related Art Conventionally, there is a semiconductor device having a structure shown in FIG. 1, for example, as a semiconductor device equipped with a reinforcing plate. In the figure, 1 is a silicon substrate (diode), 2 is an electrode made of aluminum (mut), 3 is a brazing material for bonding the silicon substrate and the reinforcing material, 4d is a tungsten plate as a reinforcing plate, and 5 is silicon. It is an insulating material such as a substrate.

FIG. 2 shows a semiconductor device in which a silicon ring is provided in place of the tungsten plate 40 since the tungsten plate 4 of this semiconductor device is expensive.

This device is first manufactured using well-known technology, for example, P of silicon.
An N-junction 6 is formed within the wafer, and then angle processing is performed to reduce the electric field strength around the wafer to form a bevel structure.

After that, the already prepared silicon ring 1 as a reinforcing material is brazed with aluminum 8, and A
Make a low resistance contact with the t-electrode 9.10. Then, the exposed surface of the angularly processed PN junction 6 is chemically etched using, for example, a hydrofluoric acid-nitric acid based etching solution, and an insulator 11 made of, for example, silicone is applied. Thereafter, the container is hermetically sealed and the semiconductor component is completed.

However, although this semiconductor device is less expensive than the semiconductor device shown in FIG. 1 because it does not use expensive tungsten, it has the following drawbacks.

■ The manufacturing process is longer because there is a process of brazing the silicone and silicone ring 1.

■ Positioning is required to combine two materials (
When placing it in a container, precision is required for brazing, assuming that it is guided by the outer diameter of the silicon ring r).

■ Aluminum 1 can be considered as a material for brazing silicon and silicon ring 7, as shown in Fig. 2, but it is also possible to use glass material in addition to silicone rubber as insulator 1 for the PN junction 6. In this case, when the aluminum 8 melts during glass firing and then hardens again, it gives distortion to the glass and causes glass cracking.

■ Processes such as brazing silicone ring 1 after surface processing of PNli% are easy to damage.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide an inexpensive semiconductor device that has strong mechanical strength at the peripheral edge of the substrate and that can be obtained through a simple manufacturing process.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 3, reference numeral 21 denotes an N-type silicon substrate, and this silicon substrate 21 has a lower peripheral edge portion thicker than other portions, and an upper surface having a negative bevel structure. Further, 22 is a P shadow region formed on this silicon substrate 21, 23 is a type 1 region, and z4 is an insulator such as silicon rubber.

That is, in this semiconductor device (diode),
By making the periphery of the silicon substrate 21 thicker than the other parts, mechanical damage can be prevented, and by making the thickness of the part where current flows substantially the same as before, the power inside the element can be reduced. This is to suppress the increase in losses.

Although the semiconductor device shown in FIG. 3 has a negative bevel structure, a positive bevel structure as shown in FIG. 4 is often used in high voltage semiconductor devices. In the figure, reference numeral 31 denotes an N-type silicon substrate having the same shape as the silicon substrate 21 shown in FIG.
2 is the P shadow area, 3s is the 1 type area, J4 is the 7 node electrode,
-35 is a cathode electrode, S6 is a groove formed in the thick portion of the silicon substrate J1, and 31 is an insulating material coated on this spool s6.

Hereinafter, the manufacturing process of this semiconductor device will be explained with reference to FIGS. 5(1) to (). First, as shown in FIG. 5(1), an N-type silicon substrate S1 having a resistivity of 1000.alpha., a thickness of 1.5 mm, and a diameter of 40 mm is prepared.

Then, this silicon substrate 31 is chemically or mechanically processed to have a depth of 1-1 diameter of 3 as shown in FIG. 5(b).
Next, as shown in FIG. 5(-)K, a P-type impurity of, for example, &D is diffused to form a P-type impurity 32, and then, as shown in FIG. As shown in Figure 5 (1) K, an electrode material of, for example, aluminum is brought into low-resistance contact with both surfaces of the anode electrode J4 and cathode electrode J4. Figure 5 (-)
As shown in FIG. 3, a groove 3# is formed corresponding to the inner thickness of the silicon substrate S1, and the fractured layer is removed using a hydrofluoric acid-nitric acid based etching solution to remove the silicon f A and O insulator 3.
1, the structure shown in FIG. 4 is obtained.

In this way, in this semiconductor device, the conventional brazing process is unnecessary, so that the drawbacks such as the above-mentioned points 1 to 2 are eliminated.

6 to 10 respectively show other embodiments of the present invention, and hereinafter, the same components as in the above embodiments will be given the same reference numerals and their explanation will be omitted. FIG. 6 shows a semiconductor device shown in FIG. 5 in which a bevel groove 3# is provided on the back surface of a substrate 31 and an insulator 39 is applied. FIG. 7 shows a negative bevel structure with a substrate 31 (peripheral KIIL portion 40 on the upper surface of D).
is provided to make it easier to apply the insulator 41. Further, the diagram wIiB shows a case where the semiconductor device is a thyristor, and the substrate 4z has a positive bevel structure from both sides.

In the figure, 43 is a P shadow area, 44 is a 1-shape area, and 46
is the P shadow area, 46 is the cathode electrode, 41 is the dirt electrode,
48 is an anode electrode, 49 to 52 are bevel grooves, 53
~5# is an insulator made of glass material. Pth shadow area, 6
0 indicates a cathode electrode, 61 an anode electrode, 61 a bevel groove, and 63 an insulator made of silicone rubber.

In the above embodiment, each region was formed by diffusion after adjusting the shape of the substrate, but as shown in FIG. 10, after diffusion, the silicon substrate 64 was used as an electrode, 6# was an anode electrode, and σ
9 is an insulator.

As described above, according to the present invention, the peripheral edge of the semiconductor substrate made of the same material is made thicker than the other parts, so the mechanical strength of the peripheral edge of the substrate is increased, and the manufacturing process is simple and inexpensive. This makes it possible to provide a semiconductor device with excellent performance.

[Brief explanation of drawings]

1 and 2 are sectional views of a conventional semiconductor device, FIG. 3 is a sectional view of a semiconductor device according to an embodiment of the present invention, and FIG. 4 is a sectional view of another embodiment of the invention. , 5th
Figures (a) to (•) are cross-sectional views showing the manufacturing process of the device shown in Figure 4, and Figures 6 to 10 are cross-sectional views showing other embodiments of the present invention. 21...N type silicon substrate, 22...P shadow area, 2
3...N shadow area, 24...Insulator. Applicant's representative Patent attorney Takehiko Suzue Figure 13ff m; Figure 4 Figure 5 Figure 8 Figure 9 Commissioner of the Patent Office Shima 1) Haruki Tono 1, Case Indication Patent Application No. 105330'1983' 2 , Name of the invention Semiconductor device 3, Relationship with the case of the person making the amendment Patent applicant (307) Tokyo Shibaura Electric Co., Ltd. November 24, 1981 6, Drawing subject to the amendment 7, Contents of the amendment Not included in the attached sheet As shown in Figure 5, ``Figure'' is added to the second page of one drawing to form Figure 5 (1) to (dl).

Claims (2)

[Claims] (1) A semiconductor device characterized in that a peripheral portion of a semiconductor substrate made of the same material is thicker than other portions. (2) The semiconductor device according to claim 1, wherein the thick portion of the peripheral edge portion is slightly surface-treated from at least one side.