Method for separating chips from diamond wafer
First Claim
1. A method for separating chips from a diamond wafer, the diamond wafer comprising:
- (a) a substrate;
(b) one of a polycrystalline chemically vapor-deposited diamond layer and a single-crystalline chemically vapor-deposited diamond layer each formed on the substrate; and
(c) a plurality of microelectronic elements formed on the chemically vapor-deposited diamond layer;
the method comprising the steps of;
(1) forming front-side grooves on the chemically vapor-deposited diamond layer by laser processing, the front-side grooves having a depth {fraction (1/100)} to 1.5 times the thickness of the chemically vapor-deposited diamond layer;
(2) removing by a plasma the thermally decomposed cuttings produced during the laser processing;
(3) forming back-side grooves on the substrate by dicing the substrate with a diamond saw blade such that the back-side grooves are in alignment with the front-side grooves; and
(4) breaking the diamond wafer by applying mechanical stresses to separate chips each having a single microelectronic element.
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Accused Products
Abstract
A method for separating chips from a diamond wafer comprising a substrate, a chemically vapor-deposited diamond layer, and microelectronic elements, with the microelectronic elements protected from thermal damage and degradation caused by the thermally decomposed cuttings produced during the processing steps. (1) Front-side grooves 6 are formed on the chemically vapor-deposited diamond layer 2 by laser processing using a laser such as a YAG, CO2, or excimer laser each having a large output so that the grooves 6 can have a depth 1/100 to 1.5 times the thickness of the diamond layer. (2) The thermally decomposed cuttings produced during the laser processing are removed by using a plasma. (3) Back-side grooves 9 are formed on the substrate 1 by dicing such that the back-side grooves 9 are in alignment with the front-side grooves 6. (4) The diamond wafer 4 is divided into individual chips 10 by applying mechanical stresses.
47 Citations
6 Claims
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1. A method for separating chips from a diamond wafer, the diamond wafer comprising:
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(a) a substrate;
(b) one of a polycrystalline chemically vapor-deposited diamond layer and a single-crystalline chemically vapor-deposited diamond layer each formed on the substrate; and
(c) a plurality of microelectronic elements formed on the chemically vapor-deposited diamond layer;
the method comprising the steps of; (1) forming front-side grooves on the chemically vapor-deposited diamond layer by laser processing, the front-side grooves having a depth {fraction (1/100)} to 1.5 times the thickness of the chemically vapor-deposited diamond layer;
(2) removing by a plasma the thermally decomposed cuttings produced during the laser processing;
(3) forming back-side grooves on the substrate by dicing the substrate with a diamond saw blade such that the back-side grooves are in alignment with the front-side grooves; and
(4) breaking the diamond wafer by applying mechanical stresses to separate chips each having a single microelectronic element. - View Dependent Claims (2, 3, 4, 5, 6)
(a) oxygen;
(b) one of the CF-family gases that are CF4, C2F6, CHF3, and C4F8; and
(c) a mixed gas of oxygen and one of the CF-family gases.
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4. A method as defined in claim 1, wherein when the depth of the laser processing of the chemically vapor-deposited diamond layer is at least the thickness of the chemically vapor-deposited diamond layer and when the substrate is made of one of sapphire, AlN, or GaAs, the gas for producing the plasma for removing the thermally decomposed cuttings is a gas selected from the group consisting of:
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(a) one of the CH-family gases that are CH4 and C2H6; and
(b) one of the Cl-containing gases that are BCl3 and CCl4.
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5. A method as defined in claim 1, wherein the laser for the laser processing is one of a YAG laser, a CO2 laser, or an excimer laser each producing a laser lightwave having a wavelength of 250 to 1,120 nm.
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6. A method as defined in claim 1, wherein the depth of the back-side grooves formed on the substrate by dicing the substrate with a diamond saw blade is such that the remaining thickness of the substrate is at most 100 μ
- m.
Specification