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US 4,052,251 AGranted
Method of etching sapphire utilizing sulfur hexafluoride
AssigneeRCA Corporation
InventorCharles Edward Weitzel
Life of this patent
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Abstract
A process for forming a blind hole having an isosceles trapezoidal cross-section in a sapphire substrate using a sulfur hexafluoride gas etchant and an etch mask of silicon nitride on top of silicon dioxide. A composite of sapphire, silicon dioxide and silicon nitride wherein silicon dioxide is located in between the sapphire and the silicon nitride; and the silicon nitride and silicon dioxide are congruently apertured.
Claims13
A process for forming blind holes in a sapphire or physico-chemically equivalent substrate comprising:
- a. depositing a layer of silicon dioxide having a first thickness adjacent a surface of the sapphire substrate;
- b. depositing a layer of silicon nitride, having a second thickness, adjacent the silicon dioxide;
- c. defining a preselected pattern having an aperture in a mask comprised of the silicon nitride and the silicon dioxide;
- and
- d. exposing the mask and portions of the sapphire substrate unprotected by the mask to a gas mixture comprised of sulfur hexafluoride gas and a carrier gas at a temperature less than 1,050.degree. C for a time period sufficient to form said blind holes.
2 more elements
A process for forming blind holes in a sapphire substrate comprising:
- a. depositing a first layer of silicon dioxide having a first thickness adjacent a surface of the sapphire substrate;
- b. depositing a layer of silicon nitride having a second thickness, adjacent the first layer of silicon dioxide;
- c. depositing a second layer of silicon dioxide, having a third thickness, adjacent the layer of silicon nitride;
- d. defining a preselected pattern having at least one aperture in a mask comprised of the first layer of silicon dioxide, the layer of silicon nitride, and the second layer of silicon dioxide;
- and
- e. exposing the mask and portions of the sapphire substrate unprotected by the mask to a vapor comprised of sulfur hexafluoride and a carrier gas at a temperature no greater than 1,050.degree. C for a time period sufficient to form said blind holes.
3 more elements
Dependencies are inferred from the claim text.