Front End of Line

The most common method for developing the resist is immediately after the patterning process. However, in specific applications, it can be done within a full batch of wafers using typical developers such as 2.6% TMAH or 3.6% KOH.

Oxide etching is required at various stages of chip manufacturing. As a result, typical mixtures such as BOE 7:1 or 10:1, BHF, and HF in different concentrations are used. Typical uniformity values for this process are as follows: <1% for within-wafer uniformity, <2% for wafer-to-wafer uniformity, and <2% for batch-to-batch uniformity.

Thin oxides such as tunnel oxides, channel oxides, and gate oxides can be etched with the inline spiking technology. Low amounts of concentrated HF are spiked into a DI water stream to create a low concentration. Out of that flexible mixtures can be created. That makes it simple to adjust the etch rate and the removal. Removals of just a few angström up to hundrets of angströms adjustable within the recipe.

In the manufacturing of MEMS (Micro-Electro-Mechanical Systems), we often need to create tiny spaces in silicon to build sensors. To achieve this, we deploy either KOH or TMAH chemicals for etching. We carefully manage the concentration and temperature of these chemicals in the equipment.

To shape glass and create specific gaps, channels, or flow cells, we use a wet etching process. This process entails removing several microns of glass by using concentrated HF, which typically ranges from 40% to 49%, and involves high temperatures.

SiN can be etched entirely or partially for specific purposes, and the choice of chemicals depends on the intended goal. Regardless of the etching purpose, achieving uniformity of less than 1% at the wafer level is essential.

Etching poly-silicon, a commonly used material for gates and various applications, involves the use of an acid mixture to achieve a smooth patterning process.

Dry etching steps within FEOL result in the formation of various kinds of polymers. Siconnex’s self-developed Post Etching Residue Clean (perc™) enables the complete removal of 100% of these polymers.

Polymers generated during dry etching are removed using solvent-based cleaning solutions.

The most cost-effective method for removing photoresist is ozone-based stripping. Photoresist stripping with ozone is also possible for exposed metals. Most metals are not affected by ozone as an oxidizer. With various parameter options and expertise, SicOzone is also a viable choice in BEOL.

Regardless of resist type (negative, positive, implanted, or treated), solvent-based solutions are used for stripping these resists.

When stripping a photoresist via plasma, some residues may remain on the surface, referred to as „ash.“ To clean these residues, multiple options are available, including the use of SicOzone, a solvent-based media or a mixture of sulfuric and peroxide.

Sicozone clean is a versatile solution widely used in chip manufacturing. It serves various purposes, including cleaning organics and metals, as well as performing oxide etches. Applications range from pre-implantation to furnace processses by addressing gate oxides, tunnel oxides, and channel oxides. Additionally, it is deployed in advanced packaging for diced wafers. Standard benchmarks include particle counts below 20 @ 0.12µm, contamination levels below 1E10 for metals, and uniformities less than 1%. Furthermore, it boasts minimal chemical and water consumption while delivering high cleaning efficiency.

RCA Clean is a conventional method used in semiconductor processes for cleaning organics, metals, and performing oxide etches. It meets industry standards with particle counts consistently below 20 @ 0.12µm, minimal metal contamination below 1E10, and uniformities consistently less than 1%. This well-established technique remains effective in chip manufacturing for maintaining cleanliness and performance.