JP2550048B2 - Etching liquid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary of the Invention] An etching solution comprising cerium ammonium nitrate, ammonium nitrate and an aqueous solution of sodium hexametaphosphate is provided.

[Industrial applications]

The present invention relates to an etching solution for etching chromium or chromium compounds.

[Conventional technology and problems]

Conventionally, as an etching solution for etching chromium, chromium compounds, etc., ceric ammonium nitrate ((N
An aqueous solution containing H ₄ ) ₂ Ce (NO ₃ ) ₆ ) and perchloric acid (HClO ₄ ) (hereinafter referred to as etching solution A) is used.
This etching solution A has a high etching rate, and it is difficult to control etching in the dipping process.

So, instead of perchloric acid, add ammonium acetate (CH ₃ COONH ₄ ) which has etching rate controllability,
Also, in order to improve the wettability on the etching surface, sodium hexametaphosphate ((NaP
Aqueous solution containing O ₃ ) ₆ ) (hereinafter referred to as etching solution B)
Can be considered. Note that sodium hexametaphosphate also has the effect of slowing the etching rate.

However, the above-mentioned etching solution B (when approximately 25 ° C. or higher, NO ₃ ⁻ roots of cerium ammonium nitrate in the solution and CH ₃ COO ⁻ or OH ⁻ roots of ammonium acetate are substituted, and Ce ^IV (N
^{_{O 3 -) n (OH -}} ) m (CH 3 COO -) about 6 precipitation of _l is 25 ° C. or higher
It occurs in 0 days and deterioration of the etching solution is observed.

Therefore, it is an object of the present invention to provide a new etching solution which improves the controllability of the etching rate and the wettability of the solution and does not cause precipitation even at 25 ° C or higher.

[Means and Actions for Solving Problems]

According to the present invention, the above problem is solved by an etching solution containing cerium ammonium nitrate, ammonium nitrate (NH ₄ NO ₃ ) and sodium hexametaphosphate (trade name: Calgon).

According to the invention, ammonium nitrate is 5.0-7.5% by weight.
It is preferable to contain from the viewpoint of preventing deterioration of the etching solution,
Further, it is effective for the wettability of the liquid and the etching characteristics to contain sodium hexametaphosphate in an amount of 0.1% by weight or less.

As described above, and it is the etchant B results in a precipitate which precipitate is dissolved in nitric acid (HNO _3), since it produces a simultaneous ammonium nitrate during precipitation _{(NH 4 NO 3), NH} 4 NO 3 in the etching solution B The inventor considered that the deterioration of the liquid can be prevented by adding.

Therefore, as a result of conducting a high temperature storage investigation and an etching characteristic investigation by adding about 1.5, 3.0 and 7.5 wt% of ammonium nitrate to the etching solution B, respectively, the effect of preventing deterioration of the solution was obtained, and further shown in FIGS. 1 and 2. Thus, the etching rate controllability was also obtained.

That is, FIG. 1 shows an etching rate for forming a pattern of metallic chromium, for example, 1 is only the etching solution B (data is), 2 is NH ₄ N in the etching solution B.
Addition of 1.5% O ₃ (data is x), 3 is etching solution B with addition of 3.0% NH ₄ NO _3. And 4 is the one in which 7.5% of NH ₄ NO ₃ is added to the etching solution B. The results are shown below. From FIG. 1 to etching solution B
It can be seen that the etching rate becomes smaller when more NH ₄ NO ₃ is added.

FIG. 2 shows the side etching rate after forming the chromium pattern shown in FIG. The same etchant and additive were used as in the case of FIG. Second
Also in the figure, as in FIG. 1, it can be seen that the etching rate is decreased by adding more NH ₄ OH ₃ to the etching solution B.

From these facts, it was found that ammonium acetate in the etching solution B is the cause of the deterioration of the solution, and that ammonium nitrate also has an etching rate controllability. From this result, it is considered that the substitution of ammonium acetate and ammonium nitrate in the etching solution B has the effect of preventing the deterioration of the solution and has the same etching controllability as the etching solution B.

〔Example〕

 Examples of the present invention will be described below.

An etching solution C-1 containing about 17.0% by weight of ceric ammonium nitrate, about 6.5% by weight of ammonium nitrate, about 0.035% by weight of calgon and the balance of water was prepared. Etching solution C containing about 7.5% by weight of ammonium nitrate in the above composition
-2 was similarly created.

In FIG. 3, the etching solution B, the etching solution C-1,
It shows the etching rate of chromium obtained by using each of the etching solutions C-2. In the figure, 5 is the etching solution B 6 shows the results of the etching solution C-1 (data x) and 7 shows the results of the etching solution C-2 (data Δ). As shown in FIG. 3, the etching rates are etching B and etching solution C.
-1, the etching solution C-2 had almost the same level of etching characteristics. Further, FIG. 4 shows the side etching rate after forming the chromium pattern shown in FIG.

In FIG. 4 as well, similar to the result of FIG. 3, the side etching rate of the etching solution B and that of the etching solutions C-1 and C-2 were almost at the same level.

Moreover, the etching liquid C-1 and the etching liquid C-2 are
No deposit was formed and deterioration of the liquid was hardly observed even after 90 days of storage at high temperature of 35 ° C.

〔The invention's effect〕

As described above, the etching solution C according to the present invention is 25
It does not cause deterioration of the liquid even at a temperature of ℃ or more, and has the effect of controlling the etching rate.

[Brief description of drawings]

1 and 2 show an etching solution B and an etching solution B.
The etching rate of chromium and the side etching rate of each of the etching solutions obtained by adding three kinds of ammonium nitrate to the above are shown in FIGS. 3 and 4, respectively.
The etching rates of chromium and the side etching rates are also shown for the etching solutions C-1 and C-2.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Minor Hirose 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor, Mitsuhiko Sano 236, Nakai, Tatsuno-cho, Tatsuno-shi, Hyogo Nagase Chemical Industry Co., Ltd. (72) Inventor Yoshiaki Horiuchi 236 Nakai, Tatsuno-cho, Tatsuno-shi, Hyogo Nagase Chemical Industry Co., Ltd. (72) Inventor Mizuyo Kurahashi 236 Nakai, Tatsuno-cho, Tatsuno-shi, Hyogo Nagase Chemical Industry Co., Ltd.

Claims (3)

(57) [Claims] 1. An etching solution containing cerium ammonium nitrate, ammonium nitrate and sodium hexametaphosphate. 2. The etching solution according to claim 1, containing 5.0 to 7.5% by weight of the ammonium nitrate. 3. The method according to claim 1, wherein the content of sodium hexametaphosphate is 0.1% by weight or less.
The etching solution according to the item.