JPS58112350A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To allow a good patterning even with large film thickness and thus attain a desired alpha ray blocking effect, by using an SiO as the alpha ray blocking film material, and accordingly forming the alpha ray blocking film by SiO by a lift- off method. CONSTITUTION:A layer 7 is removed, and, with a layer 6 as a mask, a layer 5 is patterned. Thereafter, an SiO evaporation is performed. It is necessary that the SiO source does not contain the alpha ray source, but a normal SiO evaporation source is satisfactory, then an SiO evaporated layer 8 becomes dull at the end part slightly, but generally a flat film is formed. By removing the layer 5 after the SiO evaporation is finished, the layers 6 and 8 stacked on the layer 5 are removed together, and thus the desired pattern of the SiO layer 8 is obtained. Since the layers 5 and 6 becomes difficult to be removed, when the SiO evaporated layer 8 is evaporated much higher than the layer 6, the thickness of the SiO layer is adjusted by the thickness of the layer 5. When the layer 5 is of resin such as polyimide, the layer 5 is removed by fusing by the mixed solution of e.g. hydrogen and ethylene diamine, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technology of the Invention Publicly Funded The present invention relates to a semiconductor device, particularly a semiconductor device that effectively blocks alpha rays, and a method for manufacturing the same.

(2) Background of the technology Several years ago, it was discovered that alpha rays cause soft errors that disrupt information in IC memory. Alpha radiation sources are radioactive substances (e.g. uranium, thorium, etc.) contained in packages, etc.
Coating with polyimide, silicone resin, etc. is used as a method for blocking wires. However, it is difficult to coat polyimide very thickly, and silicone resins have problems in terms of heat resistance, so effective αm [applanation & OHIA] is desired.

(3) In contrast to the conventional technology, in order to protect information, etc. from alpha rays, there is a way to prevent the intruding alpha rays from acting on the information section! Although theoretically conceivable, it is practical to rely on a method of preventing alpha rays from entering the element portion of the semiconductor device. The general conditions for an α-ray blocking film formed on a semiconductor device are:
It is a material that does not emit radiation, ■ It is possible to obtain a thickness sufficient to effectively block α radiation, ■ It has high productivity such as evaporation rate in relation to 0, ■ Butter (1) heat resistance due to the relationship with device manufacturing conditions;

Polyimide is widely used as an α-ray blocking film mainly because of its heat resistance, but there are problems in forming a film with a desired shape and thickness. Silicone resins have problems in terms of heat resistance. Further, for example, 8-μm ρ is not used as an α-ray blocking film because its deposition rate is very slow, resulting in poor productivity.

(4) Excellent αmft that addresses the aii points in the prior art, which exceed the purpose of the invention! It is an object of the present invention to provide a blocking film material and an advantageous method of manufacturing such a semiconductor device.

(5) Structure of the Invention The gist of the present invention is as follows:
It is possible to use x id@J as the α-ray blocking film material, and to form the α-ray blocking film according to 810 by a seven-off process (Lth -off process).

Sto Vapor Film Co., Ltd. has a density of approximately 2.2 f/m", which is larger than polyimide (approximately 1.1 to 1.5 feet"), so in terms of α-ray blocking function, it is better than polyimide if the film thickness is the same. In other words, it has the advantage that the film thickness required to obtain a specified α-ray blocking efficiency is even thinner than that of polyimide.Furthermore, it has excellent heat resistance and is thicker (approximately 400 times thinner than polyimide).
It can withstand up to about 1100℃ compared to ~500℃), can form a film with a relatively uniform thickness (polyimide has a low viscosity and becomes arcuate when tinged with O), and has a high deposition rate (e.g. 8tO, IlO is several p for Klksrn1 hour
m1 minutes), and patterning is also possible using the lift-off method described later. From these O, it is clear that 1%0 is excellent as an α-ray blocking film material.1
α′l11m at 9! If you are trying to make a stop, you will probably have dozens to hundreds of voices to play. Although there is no specific method for forming the 810 layer O, it can rely on the following lift-off method, which is another aspect of the IjjO of the present invention.

The lift-off method is the location where the final pattern should be applied (
For convenience, this will be referred to as a "pattern site." ) A layer is formed at a position higher than the pattern area using the material to form the final pattern and the material 14 at locations other than ), and then this level difference O
A method of forming or laminating a layer of material l to form a final pattern on a certain structure O, and then removing the material l together with the material laminated thereon, thereby removing the material l at the pattern site. point to. In the present invention, material B is StO), and the pattern portion is ! This is the semiconductor element portion (see 3 in FIG. 1) where the l1OIIIa line blocking film is to be formed.

The remainder will be specifically explained using examples.

(6) Example of aO Refreshing In FIG. 1, a chip 2 of a semiconductor element is formed on Waeno Sl. The element portion 3 of the chip 2 that should be protected by an α-ray blocking film is indicated by diagonal lines.

The process based on the lift-off method will be explained with reference to FIG. 2, but the semiconductor chip 2 is omitted in FIG. 2 for simplicity.

First, a layer 5 was formed to lift the non-patterned parts onto the wafer 1 after forming the semiconductor device.

It is preferable that the layer 5 is made of heat resistant material such as polyind.The thickness of the 840 layers that can be formed is approximately the same as that of the layer 5. Shape it to the desired thickness, about 10 to several 100 microns.

Although it is possible to pattern this layer 5 directly, it is also possible to pattern the layer 5 by, for example, low-temperature CVD or sputtering, such as P8GII, N4 layer, 810 layer, etc. This layer plays the role of a root (umbrella) during the 6SIO deposition, and is not removed by the process of removing layer 5 in the pattern area, and has the strength to support the 8I0 deposited layer. It is my own privilege to have it.

Although layer 6 may also be patterned directly,
Furthermore, a conventional resist 7 is applied on top of the resist 7, and after the resist pattern is formed, a pattern is formed by etching or the like. These treatments depend on conventional methods.

Next, layer 6 is applied with layer 7 and layer 6 is used as a mask.
patterned. It is preferable that these treatments are carried out in the same process.For example, in the case of general lubricant, 0. It was possible to rely on treatments such as processing in plasma. The situation at this time is shown in Figure 2-), but as seen in Wi, the ashing or etching of layer 5 is similar to that of layer 6.
It proceeded in the lower bunker. After the formation of this ASTO layer, layer 5
and 6 have the effect of making it easier to remove them.

After this, Bto was deposited. Although it is necessary that the source does not contain an α-source, a normal S&O deposition source is sufficient. As seen in Figure (C), the s&0 vapor deposited layer 8 was slightly sagging at the edges, but a generally flat film was formed. By removing layer 5 after the 8io vapor deposition, layers 6 and 8 laminated on layer 5 were removed together to obtain the desired pattern of 850 layers 8 (see Figure 2(d)). ), if the 1840s deposited layer 8 is deposited on a platform that is higher than layer 6, it will be difficult to remove layers 5 and 6, so as mentioned above, the thickness of layer 5 will be 810 layers. When the adjusted O layer 5 was an O resin such as Polype, the layer 5 was removed by dissolving it with, for example, a mixed solution of hydrazine and ethylenediamine.

Although the explanation has been given above using an example of S:Oa shadow formation using the lift-off method, the present invention is not limited to these 41 runs.

When using 8i011 as an α-ray blocking agent, the film thickness is generally quite large, so etching is difficult when patterning the SIO film.In the so-called metal mask method, the 810 In contrast, the lift-off method according to the present invention has the advantage that the film thickness is large and good coverage can be achieved.

(7) Effects of the Invention oM') In the semiconductor device and the manufacturing method thereof provided by the present invention, the desired α-ray blocking effect can be achieved, and the industrial applicability of 4IVC is great. be.

[Brief explanation of the drawing]

Figure 1 shows 84 mm in a round conductor element carved on a wafer.
FIG. 2 is a diagram showing a 011 pattern and a partially enlarged cross-sectional view of the diagram in one step of a lift-off method for forming the pattern. 2nd vA is a schematic cross-sectional view sequentially showing the steps of forming a base 8i0111 on the present invention 1111 by a lift-off method. l...Wafer 2--semiconductor element, 3...α-ray element film (8i0) pattern, 4...terminal layer, 5...heat-resistant resin layer, 6...film, film... Resist, 8...S false 0 vapor deposited film. Patent originator Fujitsu Ltd. Patent application agent Akira Aomi Patent attorney Kazuyuki Nishidate Patent attorney Yukio Uchida Patent attorney Akira Yamaguchi

Claims (1)

[Claims] 1. A semiconductor device in which the α-ray blocking film is made of Gtol and 4I mold. 2. A method for manufacturing a semiconductor device having an α-ray blocking film formed by ll1O, forming a lower layer on a substrate including a semiconductor element portion to be covered by gio-etching, selectively etching the wrinkled lower layer, The total mVcst on soO. After forming the film and removing the lower layer, the 9810 film laminated on top of the film is also formed into a 111*L pattern, thus forming an 8i0 pattern with a thick pattern. A method for manufacturing a semiconductor device. 3. A polyimide layer of desired thickness is formed as the final S10 film on the substrate containing the semiconductor element portion to be covered with the 8NO film, and a thin polyimide layer that can withstand the etching process of the polyimide layer and the StO film formation process is formed on top of it. Form a tungsten plate layer, selectively etch the ridged roof layer using a resist method as needed, and use the pattern formed by this method to etch the borded layer into the same pattern. , then forming an SIO film of the desired thickness on the entire surface,
The claim is that the IFI feature is that by subsequently removing the polyimide layer, the SiO film deposited thereon is also removed, thereby forming an S-shaped film having a desired thickness and pattern. [The method described in item 82.