JPS58173847A - Manufacture of element - Google Patents

Abstract

PURPOSE:To improve the reliability of the element by forming primary wiring of three layers, in which Cr, Ni and a Cr-Ni alloy are combined, onto a BSG board, superposing Si3N4 and amorphous Si through a plasma CVD method and minutely processing them and executing secondary wiring by Al. CONSTITUTION:Primary wiring of three layers formed onto the BSG substrate is shaped in the structure of Cr-Au-Cr or a Cr-Au-Ni.Cr alloy or a Ni.Cr alloy- Au-Cr, Si3N4 and amorphous Si and laminated in succession through plasma CVD and processed minutely, and secondary wiring by Al is superposed. According to the constitution, cracks are not generated in BSG during manufacture, a primary wiring layer is not damaged by an etching liquid in case of the minute processing of a laminated film of Si3N4 and amorphous Si and the patterning of the secondary wiriing made of Al, and the element with wiring having reliability is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention fabricates an element from silicon nitride and amorphous silicon that are sequentially formed on a borosilicate glass substrate, which is an alkali-free glass, by a 6ζ plasma chemical vapor deposition method (plasma CVD method). The method is characterized by the wiring material. The elements include, for example, a group of switches using FETs, a light receiving element, and other active wires. It is well known that amorphous silicon can be used to form these devices.

To explain the present invention, primary wiring and secondary wiring formed in the element will be explained based on FIG. 1. 1st
The figure shows part of the device on 4111 acid glass. In the figure, (11 is an MIS) run sister, and (2) is a crossover. To explain in detail, (3) is the primary wiring, and (4) is the secondary wiring, and this secondary wiring 4) is L r on the borosilicate glass substrate (5) or from the primary wiring (3).
There are u+1t. In terms of manufacturing process, primary wiring (3)
is always formed before the secondary wiring (41).

(6) Silicon halenide, (7) amorphous silicon, (8
) is an organic material such as silicon nitride or polyimide, which is exposed in a compact form.

The present invention provides primary wiring and secondary wiring as explained in FIG. 1, which are far superior to the conventional wiring.

In the production Cζ of such an element, the present invention has eight layers in which the primary arrangement is chromium-gold-chromium, nichrome-gold-dichrome, chromium-gold-nichrome, or nichrome-gold-chromium in this order. structure, and the secondary wiring is made of aluminum.

Conventionally, chromium, nichrome, stainless steel, aluminum, gold, conductive indium oxide, and conductive tin oxide have been used as primary wiring. Aluminum has been used for secondary wiring. Here, the following eight restrictions are mainly imposed on the wiring material from the element manufacturing process.

l) Amorphous silicon contains hydrogen atoms in its matrix,
It is necessary to prevent this from happening or detachment from the mother's body. If this desorption occurs, the characteristics of the device will be significantly deteriorated. This is a well-known fact. Therefore, in the secondary wiring process, the base heating during aluminum vapor deposition is approximately 10
Limited to temperatures down to 0℃. That is, under such conditions, it is necessary to realize a mechanically strong bond with low electrical contact resistance at the point where the primary wiring and the secondary wiring contact. The reason why aluminum is exclusively used for the secondary wiring is as follows. In other words, it is necessary for the secondary wiring to cover considerable irregularities, and the film thickness is quite large (in some cases, the I
Lfn or higher). Therefore, it is a material that can be deposited thickly.
Aluminum is used exclusively because it is cheap and bonding is possible.

2) In the case of microfabrication of amorphous silicon or silicon nitride,
An etchant containing hydrofluoric acid is used.

In the secondary wiring process, an etchant is also used during fine processing of aluminum. Therefore, the primary wiring material must have a certain degree of cinnamon resistance against an etchant containing hydrofluoric acid or an etchant for aluminum.

8) It is a well-known fact that exclusion of alkali ions is essential in order to maintain reproducibility and reliability in device manufacturing 6ζ. For this purpose, the substrate must first be alkali-free. For this reason, fused silica or sapphire may be used as the substrate, which increases the substrate cost. Therefore, borosilicate glass is usually used as the substrate. The most easily available commercially available product is Corning 7059.

Borosilicate glass has the disadvantage that it is less resistant to acids and heat than soda glass. Therefore, this drawback can be alleviated by
A lengthy process is undesirable. Therefore, we will examine the advantages and disadvantages of the primary wiring material, and table ff11 shows the etching liquid for the wiring material related to the song. Table 2 also shows the advantages and disadvantages of conventional primary wiring materials. In Table 2, the temperature of 800° C. in the disadvantages column of chromium as the primary wiring material is the temperature experienced by the substrate when plasma CVD is applied to amorphous silicon or silicon nitride. As can be seen from Table 2, when chromium and nichrome, which are commonly used, are vapor-deposited, cracks occur on the borosilicate glass substrate, which is definitely disadvantageous. Since aluminum is used for secondary wiring, it should be avoided as a primary wiring material. Gold as a wiring material inherently has poor adhesion to borosilicate glass substrates. The other materials in Table 2 have many drawbacks and are not suitable as wiring materials. In addition to those shown in Table 2, an attempt was made to use a two-layer primary wiring structure consisting of substrate, nickel OA, and chromium, but cracks also appeared in the borosilicate glass when exposed to a temperature of 800°C. Also, the substrate - chrome - gold or the substrate -
I also tried a two-layer primary wiring made of nichrome and gold, but I still couldn't make contact with the secondary wiring, which was aluminum. As can be seen from Table 2, conventional primary wiring materials are insufficient for device fabrication.

The present invention has been made in order to solve these insufficiencies based on the above-mentioned base. That is, this was done in order to satisfy the constraints consisting of the eight points mentioned above. In this research, primary wiring was formed on a borosinate glass substrate, and then plasma/CV
Sequentially forming silicon nitride and amorphous silicon by method D,
Next, when performing microfabrication of silicon nitride and amorphous silicon, and then performing secondary wiring to obtain an element, the primary wiring is chromium-gold-chromium, nichrome-gold-nichrome, chromium-gold-nichrome, or nichrome. - It has a three-layer structure of gold and chromium, and the secondary wiring is made of aluminum. Each metal is resistively heated and deposited using a tungsten heater. At this time, the degree of vacuum is 8X10' Tor
I made it below r. Microfabrication of each metal was carried out by the lift-off method, or by the etching method shown in Table 1 after forming a resist and 7f turn. As a resist, AZ IJ1
60J (Sillaplay#!χ0FPR (manufactured by Tokyo Ohka),
OMR (*manufactured by Keioka) etc. can be used. - When chromium and gold or nichrome and gold are sequentially deposited on a silicate glass substrate, the adhesion strength of the deposited film is more than twice as strong as when gold is directly deposited on the substrate, as a result of a simple tensile test. was there. The present invention originates from this observation. The film thickness of chromium or nichrome to exhibit the above-mentioned effects may be 6^ or more. Furthermore, when the chromium film thickness or the nichrome film thickness is 200λ or more, cracks are likely to occur in the borosilicate glass substrate when exposed to a high temperature of 800°C. When the primary wiring on the borosilicate glass substrate has a three-layer structure of chromium-gold-chromium, nichrome-gold-nichrome, chromium-gold-nichrome or nichrome-gold-chromium,
The thickness of the second layer of gold is preferably 60λ or more, considering the resistivity and the degree of cracking when the three-layer structure experiences a temperature of 800°C. The desirable upper limit of the thickness of the second layer of gold should be determined by constraints from the vapor deposition process and the cost of the gold material used. Another feature of the present invention is that the chromium or nichrome in the 8th layer counted from the base (the uppermost shoulder wheel wI4 of the primary wiring) is necessary to form a contact with the aluminum of the secondary wiring. It is one essence. If these metals are not thin, peeling will occur at the contact portion between the primary wiring and the secondary wiring. Note that the aluminum for the secondary wiring is deposited while keeping the substrate at 100° C. or lower, usually at room temperature. The eighth layer of chromium or nichrome must have a thickness of 5λ or more. Usually, the thickness of the eighth layer of metal bottles (chromium or nichrome) is such that it comes into contact with various etchants and other active liquids.
Since it is often slightly corroded, the current is set to 50A or more.

8 if the 8th layer metal fineness is thicker than 700λ
When exposed to temperatures as high as 0.000C, cracks are likely to occur in the borosilicate glass substrate. The reason why the desirable upper limit of the thickness of the 8th layer of chromium or nichrome is greater than the thickness of the chromium or nichrome in the first layer is thought to be due to the relationship with the borax acid base.

Next, the present invention will be explained in more detail based on FIG.

FIG. 2 shows the basic configuration of a group of M-film transistors for driving a liquid crystal, ie, one transistor and one picture element, for explaining this embodiment. In addition, the structure shown in FIG. 2 was repeatedly constructed on borosilicate glass (7059 manufactured by Corning Incorporated). In FIG. 2, (b) 4 is the primary wiring.

The negative wiring in (b) corresponds to what is called a picture element. (
To) α◆ is the secondary wiring. (to) is a laminated portion of silicon nitride and amorphous silicon. (2) is an insulating layer for insulating the primary wiring ls@ and the secondary wiring (to), and in this example, silicon oxide was formed by sputtering, and then microfabrication was performed. (opposite axis) is approximately 600 μm, (b)
It was also approximately 500IIIn.

Table 8 shows the configuration of the primary wiring and secondary wiring performed in this example and the results thereof.

In Table 8, for the film thickness, the value displayed on the film layer monitor at the time of vapor deposition was used. At this time, the density of the film was set to ssg/cm' when nichrome was deposited. Further, nichrome was deposited by resistance heating evaporation using a commercially available nichrome wire as a source. 8th
From the table, it can be seen that chromium, nichrome, and chromium-gold, which are commonly used for wiring, all have decisive defects.
It can be seen that the wiring according to the present invention is superior.

The present invention is not restricted or limited to the above embodiments.

The present invention can be carried out as described above, and it is possible to provide an element with new and useful wiring, which has great industrial value.

[Brief explanation of the drawing]

FIG. 1 is a plan view and cross-sectional view showing wiring on a silicon silicate glass substrate, and FIG. 2 is a plan view of an element in Example 1 of the present invention. 2)...Primary wiring, (to) a◆...Secondary wiring, (to)...Laminated section, Insulating layer agent Yoshihiro Morimoto Figure 1 (A) (B)

Claims (1)

[Claims] l. Form a primary wiring on a borosilicate glass substrate, then sequentially form silicon nitride and amorphous silicon by plasma chemical vapor deposition, and then perform microfabrication of the silicon nitride and amorphous silicon, After that, secondary wiring is performed to fabricate the device, and the primary wiring shown in 8u is made of gold-chromium or nichrome-
Gold - Nichrome or Chromium - Gold - Nichrome or Nichrome -
A method for manufacturing an element in which the three-layer structure is made of gold and chromium, and the secondary wiring is made of aluminum.