Wafer-level Fabrication of a High-silica v-groove for Fiber-optic Packaging Using Deep Dry-etching with a Dual-frequency High-density Plasma

We developed a procedure for fabricating deep silica v-grooves of about 70 μm for fiber-optic applications by using a deep dry-etching with a dual-frequency high-density plasma source. This procedure has the advantages of sub-micron precision with wafer-level productivity and a high etching speed of 0.7 μm/sec. An electro-plated hard mask as thick as 8 μm that can endure the deep dry-etch was also developed. In particular, the angular inclination of the etched groove was controllable by using the flow of C4F8 gas. A fiber array block was assembled by using a v-groove chip. The location error of the fiber cores in the block was measured to be less than 0.3 μm. This confirms that the dry-etched silica v-grooves can be applied to the packaging of optical devices with wafer-level productivity and high precision.