Apparatus and method
A kind of equipment and plasma technology, which is applied in the field of end point equipment and etching features, can solve the problems of low and weak end point signals, etc.
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example 1
[0064] By way of example only, Figure 2A A schematic cross-sectional view of an exemplary substrate 34 prior to plasma etching is shown. Substrate 34 includes mask layer 36 partially covering bulk silicon carbide (SiC) layer 38 . SiC layer 38 has a thickness of approximately 100 μm. The mask layer is made of copper with a thickness of about 5 μm. The proportion of the open area 40 in the mask layer is about 0.2%. Substrate 34 further includes gallium arsenide (GaAs) layer 42 formed on gold layer 44 that acts as an etch stop layer. Under certain wavelengths of light, the SiC layer has different reflectivity properties than the GaAs stop layer. At certain wavelengths, the SiC layer has different reflectivity properties than the mask layer. At certain wavelengths, the GaAs stop layer has different reflectivity properties than the mask layer.
[0065] A white light illumination source illuminates regions of the substrate. A CMOS camera is used to capture images of the illu...
example 2
[0075] Figure 4A A schematic cross-sectional view of an exemplary silicon substrate 56 prior to plasma etching is shown. Substrate 56 does not include a masking layer. However, substrate 56 includes two buried features 58 in trenches 60 . Buried features 58 are typically packaged in, for example, SiO 2 Copper through-silicon via (TSV) plugs in a thin dielectric layer.
[0076] A region of the substrate is illuminated by an illumination source, and a camera takes successive images of the illuminated region during the plasma etching process. The illumination source is positioned to direct the incident light beam substantially perpendicular to the surface of the substrate 54, as by Figure 4A Shown by the arrow in . A very low angle of incidence (ie relative to the normal) is preferred to ensure that the incident light beam is reflected from substantially the full area of the bottom surface of the trench. If the angle of incidence is high, some parts of the bottom of the...
example 3
[0079] Figure 5 is a flowchart of the substrate verification method. The substrate to be etched is positioned on the substrate support and clamped in place. The substrate to be etched includes a visible reference pattern, such as a pattern of open areas in the mask layer. A region of the substrate including the reference pattern is illuminated by an illumination source, and a camera takes an image of the illuminated region. The processor identifies the reference pattern using image pattern recognition and / or image pattern matching techniques. If the reference pattern is present, then the correct substrate has been verified and the next stage of substrate processing can proceed. If there is a lack of reference patterns, then an incorrect substrate has been loaded into the tool and the process can be aborted.
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