Device using glass substrate anodic bonding
View Patent ↗A bonding technology is disclosed that can form an anodic, conductive bond between two optically transparent substrates. The anodic bond may be accompanied by a metal alloy, solder, eutectic and polymer bond. The first anodic bond may provide one attribute such as hermeticity, whereas the second bond may provide another attribute, such as electrical conductivity.
1. A substrate pair assembly, comprising:
a first optically transparent substrate and a second optically transparent substrate, wherein the first substrate and second substrate are bonded together by a first anodic bond and a second bond, and wherein the first anodic bond further includes:
a layer of metal material;
a first layer of metal oxide material wherein the metal oxide is the covalently bonded oxidation product of the metal material and the first optically transparent substrate; and is disposed between the first optically transparent substrate and the metal layer; and
a second layer of metal oxide material wherein the second metal oxide is the covalently bonded oxidation product of the metal material and the second optically transparent substrate; and is disposed between the second optically transparent substrate and the metal layer, to form the first anodic bond between the first optically transparent substrate and the second optically transparent substrate; and
wherein the second bond is laterally adjacent to the first anodic bond, and has a different attribute than the first anodic bond.
2. The substrate pair assembly of claim 1 , wherein the first layer of the metal oxide is about 0.3 nm to about 0.5 nm thick, and second layer of the metal oxide is up to about 10 nm thick, and the layer of metal material is at least about 50 nm thick.
3. The substrate pair assembly of claim 1 , wherein the first and second optically transparent substrates comprise ion-rich glass having a resistivity of less than about 8 ohm-cm.
4. The substrate pair assembly of claim 1 , wherein the metal layer comprises at least one of titanium (Ti), chrome (Cr), silicon (Si), cobalt (Co), aluminum (Al) and zirconium (Zr).
5. The substrate pair assembly of claim 1 , further comprising:
a microfabricated device, wherein the anodic bond defines a perimeter of a hermetically sealed device cavity formed between the first optically transparent substrate and the second optically transparent substrate, with the microfabricated device disposed within the device cavity.
6. The substrate pair assembly of claim 5 , wherein the microfabricated device comprises at least one of an emitter, detector, an attenuator and reflector of electromagnetic radiation.
7. The substrate pair assembly of claim 6 , wherein the device absorbs, reflects, transmits, focuses, emits or attenuates radiation which passes through at least one of the optically transparent substrates.
8. The substrate pair assembly of claim 1 , wherein the first anodic bond provides an attribute selected from the group of hermeticity, electrically conductivity, low rf loss, high adhesive strength, leak resistance, thermal conductivity, and the second bond provides a second, different attribute chosen from the same group.
9. The substrate pair assembly of claim 1 , wherein the second bond is laterally separated from the first anodic bond by a distance of about 100 microns or more.
10. The substrate pair assembly of claim 1 , wherein the second bond comprises one of a polymer, a thermocompression, a solder, a metal alloy and a eutectic bond.
11. The substrate pair assembly of claim 1 , wherein the second bond comprises a thermocompression bond using at least one of gold (Au), silver (Ag), or platinum (Pt), and indium (In).
12. The substrate pair assembly of claim 1 , wherein the second bond comprises a multilayer stack, with each layer having thicknesses between about 1 and about 10 microns.
13. The substrate pair assembly of claim 12 , wherein the multilayer stack includes at least one of the pairs of silicon/gold, silicon\molydenum, silicon\silver layers.
14. The substrate pair assembly of claim 12 , wherein the multilayer stack is a low temperature solder bond, and includes at least one of indium\gold, indium\silver, gold-tin/gold-copper-silver, indium\copper, antimony-lead/gold-copper-silver alloys.
15. The substrate pair assembly of claim 12 , further comprising a third bond, wherein the third bond is laterally separated from the second bond by a distance of about 100 microns or more.
16. The substrate pair assembly of claim 15 , wherein the third bond is at least one of a polymer, thermocompression, metal alloy, eutectic, a solder, a metal alloy and a eutectic bond.
17. The substrate pair assembly of claim 15 , wherein the third bond comprises a multilayer stack.
18. The substrate pair assembly of claim 17 , wherein the multilayer stack includes at least one of the pairs of silicon/gold, silicon\molydenum, silicon\silver layers.
19. The substrate pair assembly of claim 17 , wherein the multilayer stack is a low temperature solder bond, and includes at least one of indium\gold, indium\silver, gold-tin/gold-copper-silver, indium\copper, antimony-lead/gold-copper-silver alloys.