Fig. 1. Oxidation mechanism and wet etching mechanism of Cu/Ti alloy

Fig. 2. Variation trend of component concentration in Cu/Ti etchant without control

Fig. 3. Etching process and formation of taper angle

Fig. 4. Static test results of Cu etchant with copper ion concentration of 8 000 ppm

Fig. 5. The variation trend of product line width with copper ion concentration without control

Fig. 6. Titanium residue in metal oxide products

Fig. 7. Concentration control curves of each component of Cu/Ti etchant with increasing copper ion concentration

Fig. 8. Variation trend of product line width and taper angle with copper ion concentration under concentration control