JP2003328159A - Surface treatment agent - Google Patents

Abstract

(57) [Problem] To provide a surface treatment agent capable of etching titanium, tungsten, titanium-tungsten alloy and the like without discoloring solder on an electronic component. SOLUTION: 20 to 50% by weight of hydrogen peroxide and 0.00
A surface treating agent comprising 1 to 10% by weight of a phosphonic acid compound.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a surface treatment agent.
More specifically, the present invention relates to a surface treatment agent that does not cause discoloration of solder on an electronic component.

[0002]

BACKGROUND OF THE INVENTION Metal layers of titanium, tungsten and titanium-tungsten alloys are commonly used as barrier layers in electronic components. Especially in semiconductor parts,
These barrier layers are used to prevent metal ions from diffusing into the underlying semiconductor substrate and contaminating it. Conventionally, an aqueous solution of hydrogen peroxide has been used as a surface treatment agent for etching these barrier layers. By etching, titanium and hydrogen peroxide react with each other to produce titanium oxide, and tungsten and hydrogen peroxide react with each other. As a result, tungsten oxide is produced. However, these surface treatment agents have a problem of causing discoloration of solder mounted on electronic components.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an alternative surface treatment agent capable of etching a metal such as titanium, tungsten, or a titanium-tungsten alloy without discoloring the solder on the electronic component. It was made as.

[0004]

The present inventor has conducted extensive studies to solve the above-mentioned problems, and as a result, the result is 25-45% by weight.
The surface treatment agent consisting of hydrogen peroxide and 0.001 to 10% by weight of a phosphonic acid compound does not discolor the solder,
We found that we could etch metal on electronic parts,
The present invention has been completed based on this finding.

The surface treating agent of the present invention is an aqueous solution containing hydrogen peroxide and a phosphonic acid compound. The concentration of hydrogen peroxide is 25 to 45% by weight, and particularly preferably 3
It is 0 to 40% by weight. If the hydrogen peroxide concentration is lower than 25% by weight, the dissolution rate will be slow and the dissolution efficiency will decrease.
If the content is higher than the weight%, there will be a safety problem.

As the phosphonic acid compound used in the present invention, diethylenetriamine penta (methylenephosphonic acid), 3,3'-diaminodipropylamine penta (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), propanediaminetetra ( Methylenephosphonic acid), bis (hexamethylene) triamine penta (methylenephosphonic acid), triethylenetetramine hexa (methylenephosphonic acid), tri (2-aminoethyl)
Amine hexa (methylenephosphonic acid), tri (3-aminopropyl) amine hexa (methylenephosphonic acid), tetraethylenepentamine hepta (methylenephosphonic acid), pentaethylenehexamine octa (methylenephosphonic acid), hexamethylenetetramine octa (methylenephosphonic acid) ) And the like. Further, even if a part of the phosphonomethyl group of these compounds is replaced with another group such as a hydrogen atom or a methyl group, it can be used. The phosphonic acid group of these phosphonic acid compounds can be similarly used even if it is not a free acid but a salt such as an ammonium salt. Among the above, particularly preferred are diethylenetriamine penta (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), and propanediaminetetra (methylenephosphonic acid).

The phosphonic acid compounds of the present invention can be used in combination of two or more kinds.

The concentration of the phosphonic acid compound is usually
It is used in the range of 0.001 to 10%, preferably
It is used in the range of 0.01 to 5%. In particular, if the concentration of the phosphonic acid compound is low, the effect of suppressing the discoloration of the solder cannot be sufficiently obtained, so it is desirable to use at least 0.001% or more, preferably 0.01% or more. On the other hand, if the concentration is higher than 10%, the effect does not change and the economy is poor, which is not preferable.

As the preparation of the surface treatment agent, a method of adding hydrogen peroxide to an arbitrary concentration and then adding a phosphonic acid compound or a method of adding hydrogen peroxide water or water in advance and mixing these at the time of use And so on. Furthermore, a phosphonic acid compound can be additionally added during the treatment.

The surface treatment agent of the present invention can perform a stable surface treatment without losing the effect of suppressing discoloration of solder even when it is held for a long time.

The surface treatment agent of the present invention can improve the stability of hydrogen peroxide when titanium, tungsten, or a titanium-tungsten alloy is dissolved. Further, known hydrogen peroxide stabilizers such as alcohols, organic carboxylic acids and organic amine compounds can be contained.

Further, the surface treating agent of the present invention may contain other components such as an inorganic acid, an organic acid, an inorganic salt, a corrosion inhibitor or a surfactant, if necessary. For example, a lipophilic nonionic surfactant having a low HLB can be preferably used as the surfactant, and examples of such a surfactant include polyoxyethylene alkyl ether, alkylamine oxide and the like. Besides,
Examples thereof include silicone-based surfactants such as polyether modified silicone. Examples of the corrosion inhibitor include mercaptobenzothiazole and benzotriazole.

The pH of the surface treatment agent of the present invention is preferably 9 or less, and particularly preferably 3 to 8. p
When H is larger than 9, decomposition of hydrogen peroxide in the liquid is promoted, which is not preferable. The pH can be adjusted using an aqueous solution of alkali metal hydroxide, an aqueous solution of organic amine, or the like.

The treatment temperature with the surface treatment agent of the present invention is 6
It is preferably 0 ° C. or lower. When the temperature is higher than 60 ° C, decomposition of hydrogen peroxide in the liquid is promoted, which is not preferable.

The method of contacting the electronic component with the surface treatment agent is not particularly limited, and it can be carried out, for example, by dipping or spraying.

[0016]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In these tests, the color change of the solder was measured by using 40% lead 60% tin as a test piece.
% Solder substrate (5 mm × 50 mm) was used, and immersion treatment with each surface treatment agent was performed under predetermined conditions. In the measurement of solder discoloration, ∘ indicates no discoloration at all, ∘ indicates slightly discoloration, and x indicates completely discoloration.

The phosphonic acid compound used is abbreviated as follows. Ethylenediaminetetra (methylenephosphonic acid) "EDTP", propanediaminetetra (methylenephosphonic acid) "PDTP", diethylenetriaminepenta (methylenephosphonic acid) "DTPP". Incidentally, ATZ used in Comparative Examples is an abbreviation for amine tetrazole.

Examples 1 to 4 and Comparative Examples 1 to 6 The test pieces were treated with the surface treatment agent having the composition shown in Table 1 and the treatment conditions. The results are shown in Table 1. The pH was adjusted using 28% aqueous ammonia.

Examples 5 and 6 and Comparative Examples 7 and 8 The surface treatment agent having the composition shown in Table 2 was used to adjust the pH using 28% ammonia water.
It was adjusted to 7, and 100 mg / l of Ti was dissolved, immersed in a high temperature tank at 30 ° C., and left to stand. The residual rate of hydrogen peroxide is the residual rate of hydrogen peroxide after 24 hours with respect to the concentration of hydrogen peroxide before heating being 100.

[0020]

By using the surface treating agent of the present invention, the metal on the substrate can be etched without discoloring the solder on the electronic component. Further, the stability of the surface treatment agent can be improved.

[0021]

[Table 1]         Hydrogen peroxide Additive species and pH Temperature (℃) Time (min) Solder discoloration         Concentration (wt%) Concentration (wt%) Example 1 35 PDTP 5.5 20 30 ○                     0.05 Example 2 35 PDTP 2.5 20 10 ○                     1 Example 3 35 EDTP 7.2 20 10 ◎                     0.5 Example 4 35 DTPP 7.8 20 30 ◎                     Three Comparative Example 1 None 4.3 20 10 × Comparative Example 2 None 7.4 20 10 × Comparative Example 3 ATZ 2.2 20 10 ×                     0.5 Comparative Example 4 EDTA 7.6 20 30 ×                     0.5 Comparative Example 5 1,3-dimethyl- 7.6 20 30 ×                    2-imidazolidinone                    0.05 Comparative Example 6 1-methoxy-2-7.6 20 30 ×                   butanol 0.05

[0022]

[Table 2]         Hydrogen peroxide concentration (wt%) Additive species concentration (wt%) Remaining rate (%) Example 5 35 DTPP0.05 97.4 Example 6 35 DTPP0.5 98.5 Comparative Example 7 35 ATZ0.05 65.5 Comparative Example 8 35 EDTA0.05 67.9

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4K057 WA20 WB08 WB15 WE11 WE25                       WG02 WG03 WN01                 5F033 HH18 HH19 HH23 QQ08 QQ19                       QQ20 WW04 XX00

Claims (5)

[Claims] 1. Hydrogen peroxide of 25 to 45% by weight and 0.00
A surface treatment agent comprising 1 to 10% by weight of a phosphonic acid compound. 2. The surface treating agent according to claim 1, which is used for etching titanium, tungsten, and a titanium-tungsten alloy. 3. The surface treating agent according to claim 1, which has a pH of 9 or less. 4. The surface treatment agent according to claim 1, which is for preventing discoloration of solder. 5. The surface treatment agent according to claim 4, wherein the solder contains lead.