JPS58156A - Manufacture of thin-film structure for lead - Google Patents

Abstract

PURPOSE:To simply obtain a lead thin-film structure with few pinholes, by selectively opening SiO2 formed on the surface of the low-resistance poly-Si made by the chemical vapor deposition. CONSTITUTION:Poly-Si with a thickness of approximately 0.1-0.5mum is deposited on a substrate such as ceramics 4 by a conventional or plasma CVD, etc. To obtain a low resistance of approximately 10<-2>OMEGA.cm, a 1-50mol% of impurities, such as P and B, is mixed into this poly-Si. Using the wet oxidation process on the poly-Si at high temperature, an SiO2 film is formed on its surface. Finally, an opening 3 is made through the use of an HF-group etching solution. Since the SiO2 film in this constitution is formed without the use of evaporation or sputtering, the process becomes simpler and the generation of defects such as pinholes will be reduced considerably. Also, the thickness of the poly-Si layer can be reduced because of its lower resistance as compared to the sputtering method.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Background of the Invention The present invention relates to a method for producing a thin film structure for a lead. More specifically, the present invention relates to a method for manufacturing a structure including a silicon thin film lead and a silicon oxide thin film formed in contact with the silicon thin film lead.

[When a low-resistance silicon thin film is used as a lead layer in an element, the upper layer may be used as a protective film to prevent oxidation, or as an intermediate insulating layer, etc.]
A thin film of silicon oxide, etc. may be formed.

In producing such a structure, it is disadvantageous in manufacturing to form a silicon thin film and then form a thin film of silicon oxide or the like by one-step deposition, sputtering, or the like.

On the other hand, if a low-resistance silicon thin film is formed by vapor deposition, sputtering, etc., and then thermally oxidized to form a silicon oxide thin film on the surface, manufacturing becomes easy. However, in this case, there are many pinholes in the ml film, which deteriorates the protective layer function and the insulating layer function, and shortens the life of the element.

I. Purpose of the Invention The present invention was made in view of the above-mentioned circumstances, and is an improvement of the method for manufacturing a structure consisting of a silicon thin film lead and a silicon oxide thin film formed in contact with it. The main purpose is to simplify the process and improve the function of the silicon oxide thin film as a protective film or an insulating layer.

As a result of various tests of δ・t for this purpose, the present inventors found that when a low-resistance silicon thin film was formed by chemical vapor deposition and then thermally oxidized, the manufacturing method was simple and the formation process was easy. It was discovered that defects such as pinholes in the soot silicon oxide film were significantly reduced, and this led to the present invention.

That is, in the present invention, on a substrate, by chemical vapor deposition method,
A low resistance polycrystalline silicon layer is formed, and then this is thermally oxidized to form a silicon oxide layer on the surface of the silicon layer, and then a part of the silicon oxide 1- is selectively removed to expose the silicon layer. % mold.

■Specific structure of the invention Hereinafter, a specific configuration of the present invention will be explained in detail.

In the present invention, first, a low-resistance polycrystalline silicon layer is formed on a predetermined base by chemical vapor deposition.

The base used can be of various types depending on the structure of the element forming the lead, subject to restrictions on whether it can withstand the heating performed during chemical vapor deposition. In the example shown in FIG. 1, an example is shown in which it is formed directly on an insulating substrate 4 made of ceramics, glazed ceramics, or the like.

The silicon layer formed by the chemical vapor deposition method has a low resistance, and its resistance value is about 10<1 >[Omega].mu.m or less.

In order to set such a resistance value, the silicon layer is preferably made of silicon or contains silicon containing phosphorus, boron, arsenic, antimony, aluminum, or the like. Of these, in silicon, 1 mol% or more, more preferably about 1 to 50 mol% of phosphorus,
Those containing boron, arsenic, antimony, aluminum, etc. are particularly suitable.

Such a silicon layer is formed as a result of chemical vapor deposition described below.
Formed on a substrate as a polycrystal.

Further, the layer thickness is usually about 0.1 to 5 μm.

Such a silicon layer is formed on the base according to a chemical vapor deposition method.

To form a silicon layer according to the chemical vapor deposition method, silane (SiH4), silicon chloride, etc. are used as a silicon source as a volatile substance, and when other elements are included in silicon as necessary, the chloride, hydrogen, etc. The source is chemical substances, organic substances, etc. In addition, as a carrier gas, Tow, He
, Ar, etc. may be used. Then, it can be easily determined from experiments in accordance with the reaction temperature composition.

As a result of using such a chemical vapor deposition method, defects such as pinholes in the silicon oxide film formed by thermal oxidation (described later) are less likely to occur than when a silicon thin film is formed by sputtering without using the chemical vapor deposition method. In comparison, it is significantly reduced. Also, compared to when sputtering is used, the resistance of a silicon thin film when the layer thickness is the same is 1/10@
decreases to a degree.

Incidentally, the silicon layer to be etched in this way is usually photo-etched into a predetermined shape, and then a thin silicon monoxide film 2 is formed on the surface of the silicon layer 10 by thermal oxidation, as shown in FIG. Form.

Thermal oxidation may be performed in air, but it is usually preferable to perform it in a steam atmosphere or a dry oxygen atmosphere. Further, the heating temperature is 1000 to 1200°C. Thermal oxidation treatment is then carried out by holding the material at such a temperature for 10 minutes or several hours, usually about several tens of minutes.

As a result of this thermal oxidation, a silicon oxide layer 2 is formed on the surface of the silicon layer 1, generally made of Si.

A silicon oxide layer having a certain composition is formed to a thickness of several thousand λ.

Next, a part of the upper silicon oxide layer 2 is applied to the thus formed laminate, for example, as shown in FIG.
The silicon layer 1 is exposed by selective removal.

Selective removal of the silicon oxide layer 2 may be carried out using a photoetching method using an ordinary hydrofluoric acid etching solution. Further, the shape of the window 3 formed by selective removal may be appropriately determined depending on the structure of the element.

In this way, the lead thin film structure of the present invention is manufactured. After that, for example, as shown in FIG. An electrode 5 may be formed on the layer 2, or an upper thin film structure may be further laminated, and an electrode may be formed on the silicon layer 2 within the window 3, or an upper thin film structure may be formed through the window 3. By doing so-called crossover wiring with the body,
Various resistance elements, capacitor elements, inductance wires,
Various elements or circuits such as various integrated circuits are manufactured.

(2) Unique Effects of the Invention According to the present invention, the silicon oxide layer is formed without using vapor deposition or sputtering, which simplifies the process and is advantageous in manufacturing.

Furthermore, compared to the case where a silicon layer is formed by sputtering, vapor deposition, etc. and then thermally oxidized, defects such as pinholes in the silicon oxide layer are significantly reduced. As a result,
When the upper silicon oxide layer is used as a lead protection film, the lead oxidation prevention effect is extremely high, and the life of an element or circuit used under relatively poor chemical conditions is extended. Further, when the silicon oxide layer is used as an intermediate insulating layer with other thin films, the dielectric strength voltage becomes extremely high. Therefore, there is no need to increase the thickness of the silicon oxide layer, and the heat treatment time is shortened, which is advantageous in terms of horse construction.

Furthermore, since the silicon layer is formed by chemical vapor deposition, the lead resistance is reduced to 1/10 or less compared to when sputtering is used, and the silicon layer has the advantage of being thinner.

[Brief explanation of drawings]

FIG. 91 is a partially omitted sectional view for explaining the first step in the present invention. FIG. 2 is a partially omitted sectional view for explaining the second step in the present invention. FIG. 3 is a partially omitted sectional view for explaining the third step in the present invention. FIG. 4 is a partially omitted plan view showing an example of an element manufactured using the present invention. ■・・・・・・・・・・・・・・・−・Silicon layer 2・
・・・・・・・・・・・・・・・・・・European Silicon Layer Agent Patent Attorney Yo Ishii - Age 1, Age 2, Age 8

Claims (1)

[Claims] A low-resistance polycrystalline silicon layer is formed on the base by chemical vapor deposition, then thermally oxidized to form a silicon oxide layer on the surface of the silicon layer, and then a part of the silicon oxide layer is removed. A method for producing a thin film structure for a lead, the method comprising selectively removing a silicon layer to expose a silicon layer.