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Corporate Outline

Wet Polishing (CMP etc.)


With the reduction in height and size of IC packages, there is increased demand for thinner built-in die in silicon devices. Therefore, the stress relief process is carried out to improve die strength after wafer backgrinding. Furthermore, a polishing process is also required after backgrinding to improve performance for devices such as high luminance sapphire (Al2O3) substrate for LEDs, lithium tantalate (LiTaO3) / lithium niobate (LiNbO3) substrate for high-speed communication device SAW filters, and silicon carbide (SiC) substrate for power devices.
Typical CMP equipment places the wafer above and the polishing pad below. In contrast, DISCO equipment possess a feed axis and places the polishing pad above and the wafer below. This structure is called “in-feed polishing” and is used for both dry polishing and wet polishing (polishing method that utilizes typical CMP chemicals). DISCO’s wet polishing, introduced here, realizes scratch reduction, mirror surface finish, and improvements to cleanliness. Furthermore, depending on the material, an Epi Ready* finish can be achieved.

*Epi Ready: surfaces and materials that enable epitaxial growth.

Figure 1: Major stress relief processes
Figure 1: Major stress relief processes

Characteristics of Wet Polishing Process

  • Low-load, high-rotation polishing
Figure 2. Processing image of wet polishing
Figure 2. Processing image of wet polishing

Main Effects of Wet Polishing Process

  • Mirror surface finish processing
  • High cleanliness
  • Depending on the material, low number of scratches and Epi Ready finish can be achieved

Application Examples

  • Polishing for wafer production (substrate manufacturing process)
    • Silicon carbide (SiC)
    • Sapphire (Al2O3)
    • Lithium tantalite (LiTaO3) / Lithium niobate (LiNbO3)
  • Stress relief after backgrinding
    • Silicon (Si)
    • Sapphire (Al2O3)
    • Lithium tantalate (LiTaO3) / Lithium tantalate (LiTaO3) on on silicon (Si)
    • Gallium arsenide (GaAs)
    • Indium phosphide (InP)
  • Polishing before Cu-Cu bonding
  • Regeneration processing of silicon (Si) wafers
Figure 3. Polishing rate with wet polishing
Figure 3. Polishing rate with wet polishing

Compatible Equipment

Our product line-up provides highly extensible capabilities that can be used to match our customer’s operating environment and can also be used for a wide range of applications.


Please feel free to contact us with any questions or inquiries.