Diffusion bonding of crystals
First Claim
1. A method of bonding two crystals together comprising the steps of:
- depositing a layer of bond enhancing material on one of said crystals;
depositing a layer of a noble metal on said bond enhancing material;
depositing on said other crystal a low melting point metal selected from the group Sn and In;
depositing a layer of noble metal on said low melting point metal to prevent oxidation thereof; and
bringing together the noble metal layers at a temperature of between 100°
C and 200°
C and applying a pressure in excess of 50 pounds per-square-inch to cause a diffusion bond between the noble metal atoms and the low melting point metal atoms.
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Abstract
A method of bonding two crystals together is disclosed. A bond enhancing material such as chromium (Cr) is vapor deposited on one crystal, and on this is vapor deposited a noble metal such as gold (Au). On the other crystal a low melting point metal such as tin (Sn) or indium (In) is vapor deposited. In the case of In this can either be directly on the crystal or on a layer of bond enhancing material; in the case of Sn this must be on a bond enhancing material. On top of the low melting point metal a layer of the same noble metal is deposited to prevent oxidation thereof. The noble metal layers are brought into contact with each other in vacuum or inert atmosphere and pressure applied thereto at a temperature of 100° C to 150° C in the case of In and 100° C to 200° C in the case of Sn. The low melting point metal will diffuse into the noble metals and across the interface causing a bond to form by elimination of the boundary between the crystals.
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Citations
24 Claims
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1. A method of bonding two crystals together comprising the steps of:
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depositing a layer of bond enhancing material on one of said crystals; depositing a layer of a noble metal on said bond enhancing material; depositing on said other crystal a low melting point metal selected from the group Sn and In; depositing a layer of noble metal on said low melting point metal to prevent oxidation thereof; and bringing together the noble metal layers at a temperature of between 100°
C and 200°
C and applying a pressure in excess of 50 pounds per-square-inch to cause a diffusion bond between the noble metal atoms and the low melting point metal atoms. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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- 16. In a bonding process wherein one crystal material is bonded to another crystal material and wherein a noble metal is deposited on one crystal and a low melting point metal is deposited on the other crystal material, the improvement comprising, depositing a layer of said nobel metal on said low melting point metal whereby to prevent oxidation of the surface thereof, and thereafter bonding said materials by application of pressure with said noble metal layers in contact with each other to form a diffusion bond between said noble metal atoms and said low melting point metal atoms.
Specification