The simple understanding of etching is photolithography etching, which is a patterning process related to Photo Etching. It combines chemical, physical, chemical physical and other methods to selectively remove the material under the (photoresist) opening. These materials include silicon, dielectric, etc. material, metal material, photoresist, etc. Etching is to use photoresist and other materials as a masking layer, and use physical/chemical methods to remove the parts of the lower layer material that are not covered by the upper masking layer material, and further obtain the graphics corresponding to the mask pattern on the lower layer material.
Main parameters of etching: etching rate, uniformity, selectivity ratio (etching rate ratio for different materials), etching slope (anisotropy, isotropy)
What is Laser Etching
Laser etching is a sophisticated printing technique commonly used on brand labels or brand substrates.
Computers are usually used to create laser effects on surfaces such as engraving on glass, metal, wood and plastic. Another technical advantage of laser etching is the high-volume, rapid processing of materials.
There are two commonly used techniques for etching. One is wet etching. Wet etching has poor anisotropy, and sidewalls are prone to lateral etching, resulting in etching deviation. It is usually used for applications with large process sizes. Or for cleaning residue after dry etching, etc. The other is dry etching, which is a more popular etching technique at present, and plasma dry etching is dominant in dry etching. The different methods of generating plasma by plasma etching make dry etching continue to be subdivided into capacitive plasma etching and inductive plasma etching; according to the type of etched material, dry etching is mainly etching Dielectric materials (silicon oxide, silicon nitride, oxide, photoresist, etc.), silicon materials (single crystal silicon, polycrystalline silicon, and silicide, etc.) and metal materials (aluminum, tungsten, etc.).
The most widely used etch equipment is ICP and CCP, which cover the main etch applications.
- Capacitive plasma etching CCP: high-energy ions are used to etch microstructures such as deep holes and deep grooves with high aspect ratios on hard dielectric materials; high energy and low precision are used in dielectric material etching ( formation of upper-layer lines) – such as gate spacers of logic chips, hard mask etching, middle-section contact hole etching, back-end damascene and Aluminum Chemical Etching, etc., as well as 3D flash memory chip process (silicon nitride/silicon oxide ) The etching of deep grooves, deep holes and wiring contact holes, etc.
- Inductive plasma etching ICP: Etch softer and thinner materials with lower ion energy and extremely uniform ion concentration. Low energy, high precision, applied to silicon etching and metal etching (formation of underlying devices) – silicon shallow trench isolation (STI), germanium (Ge), polysilicon gate structure, metal gate structure, strained silicon (StrainedSi), metal The development direction of multi-channel etching technology in wire, metal pad (Pad), damascene etching metal hard mask and multiple imaging technology is atomic layer etching (ALE).
- ALE: technology development direction, can accurately etch to the atomic layer (about 0.4nm), and has ultra-high etching selectivity. Wide range of applications.