Etching method and quantitative analysis method of etching liquid
A quantitative analysis, etching solution technology, used in color/spectral property measurement, electrical components, semiconductor/solid-state device manufacturing, etc., can solve the problems of difficult etching rate control, reduced etching rate, and large acid consumption.
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Embodiment 1
[0126] exist figure 1 Fill 1000g in the shown etching tank (1) by nitric acid 5.2%, phosphoric acid 73%, acetic acid 3.4%, the remainder is the etchant that water forms (acid component corresponding concentration 81.1%), use heating device (7) and stirring device (11), take the etching temperature at 33°C, and strive for the uniformity of the etching solution.
[0127] While immersing the object to be etched (4) in the etchant in the etching tank (1), time measurement was started, and the etching was confirmed visually to complete, and the etching rate was calculated. The etching rate of the etching solution at the beginning of etching was 2300 Å / min.
[0128] The amount of aluminum dissolved in the etchant by etching was calculated and accumulated from the area and thickness of the etched portion removed from the substrate. The etching rate at the end of etching (the time point when the amount of aluminum dissolved by etching reached 1 g) was 2150 Å / min (about 93% of that a...
Embodiment 2
[0139] Etching was performed in the same manner as in Example 1 except that the amount of aluminum processed in Example 1 was 0.5 g. The etching termination time was taken as the time when the amount of aluminum dissolved by etching reached 0.5 g, and the etching rate of the etching solution at the termination of etching was reduced to 2200 Å / min (about 96.5% of that at the beginning of etching).
[0140] After the etching was terminated, the composition of the etching solution was analyzed in the same manner as in Example 1, and the result was 5.1% nitric acid, 71.5% phosphoric acid, and 3.4% acetic acid (the corresponding concentration of the acid component was 80.4% by weight).
[0141] Then, remove 183g etching solution from etching tank (1), add nitric acid 5.5% by weight, phosphoric acid 75.4% by weight again, the 183g liquid of 3.4% by weight of acetic acid, at this moment, each acid concentration is nitric acid 5.2% in the etching solution of etching tank 1 % by weight, ...
Embodiment 3
[0146] An etching solution composed of a mixed acid solution (the balance being water) having a nitric acid concentration of 14.8% by weight, a phosphoric acid concentration of 59.9% by weight, and an acetic acid concentration of 5.0% by weight was prepared. Then perform the necessary analysis in the order described below.
[0147] (1) Quantitative analysis of nitric acid
[0148] First, 6 g of the above mixed acid solution was diluted with water to prepare 250 g. Prepare an aqueous potassium nitrate solution containing 25 mg of nitric acid per 1 g as a reference solution, and measure the absorbance around 302 nm. Water was used as a control solution. Make a calibration line from the relationship between the reference solution and the absorbance, and calculate the concentration of nitric acid in the mixed acid solution. The concentration of nitric acid was 14.9% by weight. Nitric acid equivalent is (14.9 (weight %) / 100) / 0.0631=2.365 (meq.). Here, 0.0631 is the amount (g) ...
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