1：Experimental Design and Method Selection:

The study involves a series of experiments to evaluate the feasibility, validity, operability, and reliability of a metal etching method. The method uses wet etching with specific etchants to isotropically etch underlying metals through pinholes in IMD films, creating larger metal-free areas to prevent electrical connections after upper metal deposition.

2：Sample Selection and Data Sources:

Samples were prepared on 4-inch silicon wafers with a 300 nm thermal oxide layer. Metal layers (Ti/Au) and IMD layers (SiO2) were deposited using electron-beam evaporation and PECVD, respectively. Pinholes were intentionally present due to deposition imperfections.

3：List of Experimental Equipment and Materials:

Equipment includes electron-beam evaporator for metal deposition, PECVD system for SiO2 deposition, optical microscope, SEM, interferometric profiler, semiconductor device analyzer, and oven for thermal cycling. Materials include silicon wafers, titanium, gold, silicon dioxide, gold etchant (mixture of I2, NH4I, ethanol), and titanium etchant (mixture of NH4OH, H2O2).

4：2). Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Process flow: Deposit Metal 1 (Ti/Au) on substrate, pattern by lift-off; deposit IMD (SiO2) by PECVD; immerse in etchants (gold etchant for 25 min, titanium etchant for 2 min) to etch through pinholes; deposit Metal 2 (Ti/Au); perform electrical and optical characterizations.

5：Data Analysis Methods:

Optical and SEM imaging for pinhole observation; electrical testing with semiconductor device analyzer to measure current density vs. applied field; statistical analysis of etched profile sizes and thermal cycling effects.