JPS59196385A - Chemical polishing liquid - Google Patents

Abstract

PURPOSE:To provide a chemical polishing liquid containing a specified organic acid, hydrogen peroxide, sulfuric acid and a surfactant, which makes it possible to polish metals without causing denaturation and deterioration of low-melting glass for sealing of window for light transmission and coating film. CONSTITUTION:The chemical polishing liquid contains at least one acid selected from among citric, malonic and succinic acids, hydrogen peroxide, sulfuric acid and a surfactant. The acids have a weak corrosive effect upon metal and have mild polishing action. Hydrogen peroxide is readily decomposable, but addition of a surfactant such as polyoxyethylene alkylamine increases its decomposition temperature and insures its use at a high temperature under a stabilized condition. The polishing liquid does not cause denaturation nor deterioration of low- melting glass used as sealant for light transmission window, coating film on a window surface and the surface of a pane itself, and a metal surface which produces high quality plating can be obtained in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides stable chemical polishing treatment without altering or deteriorating the low melting point glass that seals the light transmitting window member and the coating film coated on the light transmitting window member. This invention relates to a chemical polishing liquid suitable for use in a camp with a light transmission window sealed with low melting point glass.

Semiconductor devices used in dintal audio discs and the like are used with a laser element and the like fixed on a metal outer ring and hermetically sealed with a light-transmitting window cap. As shown in FIG. 1, this light transmission window cap 10 is made of Fe.
- A light transmitting window 16 made of hard glass or the like is formed by a low melting point glass 18 to cover the through hole 14 provided in the center of the cap member 12 on the camping member 12 made of -Ni alloy or Fe -Ni-Co alloy. It is sealed.

By the way, the hard glass used as the light transmitting window 16 has a softening point of about 700°C, so the low melting point glass 18 that seals it is heated during sealing to cause the light transmitting window 1 to soften.
6 is softened and deformed and becomes flat? A lead-based material with a sealing temperature of about 500°C is used so that the fk degree is not impaired. On the other hand, the light-transmitting window cap 10 in which the light-transmitting window 16 is sealed with the low-melting glass 18 as described above improves the sealing performance with the metal outer ring to which the semiconductor element, etc. is fixed, and has an airtight property. In order to improve the quality, plating is finally performed, but in order to seal the light transmitting window 16 using the low melting point glass 18, Fe-Ni is coated in advance.
- A metal oxide film is applied to the surface of the cap member 12 made of Co alloy or the like, and the low melting point glass 18 and the cap member 1
This is to improve the airtightness between the two. On the other hand, before plating, in order to remove this metal oxide film that becomes an obstacle during plating, and to obtain a plating film with good adhesion, a chemical polishing treatment is performed to make the metal surface shiny and smooth. It becomes necessary.

The present invention relates to a polishing liquid used in this chemical polishing treatment.

Conventional chemical polishing solutions for Fe--Ni alloys or Fe--Ni--Co alloys include those based on nitric acid mixed with chlorine ions and those based on hydrogen peroxide mixed with fluoride.

However, when the above-mentioned chemical polishing liquid is used for the chemical polishing treatment of the light-transmitting window cap 10, NO, -CI-, etc. in the polishing liquid are removed if the polishing liquid is nitric acid-based.

Each of CIl and COO- ions causes a chemical reaction with lead in the low melting point glass component, altering the quality of the low melting point glass 18.

There are some ff1it points that degrade it. In addition, in the case of hydrogen peroxide-based products, the fluoride mixed in may alter the quality of the non-reflective coating film (MgF, film) applied on the light transmission window 1G, or as described above. There is a drawback that the low melting point glass 18 is altered or deteriorated, or the surface of the light transmitting window 16 itself is eroded and its smoothness is impaired.

Therefore, in the past, when using the above-mentioned polishing liquid for a light-transmitting window cap, it was unavoidable to adjust the processing temperature, processing time, etc., but the workability was poor and the above-mentioned The negative effects of this are unavoidable, but they lead to poor airtightness and deterioration of the characteristics of semiconductor devices.

In view of the difficulties mentioned in Section 2, after careful consideration, the inventor has
All conventional products are contaminated with halogen ions, and we have come to the conclusion that these halogen ions are the root cause of excessive erosion of the glass.

The present invention provides a low-melting-point material that does not contain such corrosive halokene ions, does not alter or deteriorate low-melting-point glass or coating films, and allows chemical polishing to be carried out stably and with good workability. The purpose is to provide a chemical polishing liquid suitable for use in glass-sealed caps with light transmission windows, and its characteristics include citric acid, malonic acid,
It contains one type of acid, succinic acid, hydrogen peroxide, sulfuric acid, and a surfactant.

Citric acid is preferably used as the acid. Other materials that are mildly corrosive to metals, such as malonic acid and succinic acid, are good. Concentrations in the range of 15 g//i to 25 g/l are effective and provide a mild abrasive effect.

Although hydrogen peroxide is easily decomposed, hydrogen peroxide can be decomposed by using an appropriate surfactant, such as an ethylene oxide surfactant such as polyoxyethylene alkylamine or polyoxyethylene alkyl ether. It acts as a negative catalyst for decomposition, and in particular reduces the temperature conditions under which hydrogen peroxide decomposes, making it possible to use it stably at high temperatures and increasing the polishing speed.

The concentration of hydrogen peroxide solution is 150J/ff~250-v e
The preferred range is 0.05g/β of the surfactant.
A trace amount of ~0.1g/6 is effective.

Sulfuric acid is more corrosive to glass than nitric acid, hydrochloric acid, etc.
It is extremely low compared to acids and remains unchanged even at high temperatures. Therefore, it stably exhibits a gentle abrasive action on two metals at high temperatures. In terms of concentration, 40 companies/12-60
−/β is preferable.

(1) Table 1 shows examples at various concentration settings.

Table 1 (Miscellaneous #jJ57゛C1㎧l川田ramaIOsec) No deterioration of the coating film applied to the hard glass was observed.

In this way, in order to obtain a glossy surface that is a good plating base for Fe-Ni alloys and Fe-Ni-Co alloys, the composition range described above is necessary, and in this composition range, there is no alteration or deterioration of the low melting point glass. .

(2) Next, FIG. 2 shows the relationship between processing time and polishing amount. The composition was as follows.

Citric acid 20g/j! Hydrogen peroxide solution 200. J/E Sulfuric acid 50J/6 Surfactant 0.05 g/β Treatment start temperature 57°C Sample material A Fe-Ni-Co 54%-2
9%-17% Sample material BFe-Ni58%-42%
Since the amount of polishing necessary to apply the above-mentioned plating with good adhesion on the camping member 12 is about 10 μm to 20 μm, as is clear from FIG. 2, the processing time is 10 seconds at the processing temperature of 57°C. A short period of time is sufficient.

(3) Examined using sample material A under the conditions of (2),
Table 2 shows the relationship between polishing liquid amount (mλ)/treated metal surface area (CII+) and total bending surface condition.

Table 2 If the amount of polishing solution is small relative to the metal surface area to be treated, the temperature of the solution will rise due to the heat of reaction, causing roughness and discoloration on the metal surface, and the hydrogen peroxide solution in the polishing solution itself will decompose. It is advisable to use a sufficient amount of liquid to avoid deterioration.

As described above, the chemical polishing liquid of the present invention does not alter or deteriorate the low-melting point glass that seals the light-transmitting window, and also prevents the coating film applied to the light-transmitting window surface from changing or deteriorating. It has the remarkable effect that a metal surface for obtaining good plating can be obtained in a short time without altering or deteriorating the surface of the metal itself.

Although the present invention has been variously explained above with reference to preferred embodiments, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. That's true.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a cap with a window for light transmission, and FIG. 2 is a graph showing the relationship between processing time and polishing amount when processing with a polishing liquid according to the present invention. DESCRIPTION OF SYMBOLS 10... Cap with window for light transmission, 12... Cap member, 14... Through hole, 16... Window for light application, 18... Low melting point glass. Patent applicant Shinko Electric Industry Co., Ltd. Representative Takekio Mitsunobu

Claims (1)

[Claims] 1. A chemical polishing liquid containing one type of acid selected from citric acid, malonic acid, and succinic acid, hydrogen peroxide, sulfuric acid, and a surfactant.