FABRICATION METHOD FOR DEVICE STRUCTURE HAVING TRANSPARENT DIELECTRIC SUBSTRATE
First Claim
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1. A method of fabricating a semiconductor integrated circuit chip comprising:
- preparing a wafer including a dielectric substrate that is transparent to light and having a front surface and a back surface, a first film formed on the back surface of the dielectric substrate, a second film formed on the first film, a third film formed on the second film, and a fourth film formed on the front surface, the second film having a lower refractive index than the first and third films;
forming circuitry in and on the fourth film, and dicing the wafer into chips; and
illuminating the third film by sensing light for detection of the wafer, during said forming.
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Abstract
A semiconductor device has a transparent dielectric substrate such as a sapphire substrate. To enable fabrication equipment to detect the presence of the substrate optically, the back surface of the substrate is coated with a triple-layer light-reflecting film, preferably a film in which a silicon oxide or silicon nitride layer is sandwiched between polycrystalline silicon layers. This structure provides high reflectance with a combined film thickness of less than half a micrometer.
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Citations
18 Claims
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1. A method of fabricating a semiconductor integrated circuit chip comprising:
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preparing a wafer including a dielectric substrate that is transparent to light and having a front surface and a back surface, a first film formed on the back surface of the dielectric substrate, a second film formed on the first film, a third film formed on the second film, and a fourth film formed on the front surface, the second film having a lower refractive index than the first and third films; forming circuitry in and on the fourth film, and dicing the wafer into chips; and illuminating the third film by sensing light for detection of the wafer, during said forming. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification