What Is a Resist Coater?
A resist coater is a device used to apply a resist material to the surface of a target object, such as a substrate. A resist material is an electronic material consisting of a resin that is sensitive to light.
Resist coaters can be divided into a spin coater and a spray coater according to the coating method. The former, spin coaters, are used for resist coating. Spin coaters are capable of depositing films from one to several tens of microns thick and are suitable for coating flat surfaces.
Spray coaters are used for coating three-dimensional objects with undulating surfaces.
Uses of Resist Coaters
Resist materials applied by resist coaters are materials used in the processing of semiconductors. Therefore, resist coaters are often incorporated into the semiconductor manufacturing process.
Resist materials are used in the role of photomasks in laser processing. Although resist materials can be manually applied by hand, it is difficult to achieve uniform film pressure and other uniformities. If there are areas where the coating is not applied, or if the thickness is insufficient or uneven, subsequent processing cannot be performed properly and the quality of the product will vary.
Uniform application of resist material by resist coater is very important from the viewpoint of quality control.
Principle of Resist Coaters
As mentioned above, spin coaters and spray coaters are the most common resist coaters. Spin coaters and spray coaters differ in their coating methods.
Spin Coater
The spin coater uses centrifugal force to apply the coating. After a drop of resist material is placed on the object to be coated, the object is rotated at a high speed. The centrifugal force generated by this rotation allows the resist material to spread to every corner of the object.
When using a spin coater, the spreading of resist material may stop at undulations on the surface, making it difficult to apply the resist material to objects with severely undulating surfaces. In such cases, a spray coater may be used.
Spray Coater
A spray coater is a device that uses a spray atomization method. Resist material is applied by spraying. The mechanism for ensuring uniform application varies from device to device. Some devices move the spray nozzle to apply the coating to each part, while others rotate the object to be coated while keeping the spray nozzle fixed.