Method and apparatus for establishing electrical contact between a wafer and a chuck
First Claim
1. A method for making electrical contact between a semiconductor wafer having a dielectric layer and a wafer chuck holding said wafer, said dielectric layer having a breakdown voltage, said method comprising:
- urging a pointed contact against said dielectric layer; and
momentarily applying a voltage equal or greater than said breakdown voltage between said contact and said chuck, thereby creating an ohmic connection between said wafer and said chuck.
1 Assignment
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Accused Products
Abstract
A needle is pressed into the backside oxide of a semiconductor wafer and a voltage applied to the wafer greater than the breakdown voltage of the oxide in order to make an electrical contact with the bulk material of the wafer. A capacitor plate is provided proximate to a wafer on a chuck and a Kelvin probe is provided proximate to the wafer. A varying voltage is applied between the chuck and the capacitor plate and a voltage is monitored between the Kelvin probe and the chuck. The monitored voltage remaining constant indicates electrical contact between the chuck and the wafer.
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Citations
14 Claims
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1. A method for making electrical contact between a semiconductor wafer having a dielectric layer and a wafer chuck holding said wafer, said dielectric layer having a breakdown voltage, said method comprising:
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urging a pointed contact against said dielectric layer; and momentarily applying a voltage equal or greater than said breakdown voltage between said contact and said chuck, thereby creating an ohmic connection between said wafer and said chuck. - View Dependent Claims (2, 3)
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4. A method for determining electrical contact between a semiconductor wafer and a wafer chuck, said method comprising:
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providing a capacitor plate proximate to said wafer; providing a Kelvin probe proximate to said wafer; applying a varying voltage between said chuck and said capacitor plate; and monitoring a voltage between said Kelvin probe and said chuck, wherein said monitored voltage remaining constant is indicative of electrical contact. - View Dependent Claims (5)
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6. A method for determining electrical contact between a semiconductor wafer and a wafer chuck, said method comprising:
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providing a first capacitor plate proximate to said wafer; providing a second capacitor plate proximate to said wafer; applying a varying voltage between said chuck and said first capacitor plate; and monitoring a voltage between said second capacitor plate and said chuck, wherein said monitored voltage remaining constant is indicative of electrical contact. - View Dependent Claims (7)
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8. An apparatus for making electrical contact between a semiconductor wafer having a dielectric layer and a wafer chuck holding said wafer, said dielectric layer having a breakdown voltage, said apparatus comprising:
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a pointed contact; a contact actuator for urging said contact against said dielectric layer; and a voltage source for momentarily applying a voltage equal or greater than said breakdown voltage between said contact and said chuck, thereby creating an ohmic connection between said wafer and said chuck. - View Dependent Claims (9, 10)
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11. An apparatus for determining electrical contact between a semiconductor wafer and a wafer chuck, said apparatus comprising:
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a Kelvin probe proximate to said wafer; a capacitor plate proximate to said wafer; a variable voltage source between said chuck and said capacitor plate; and a voltage monitor between said Kelvin probe and said chuck, wherein a monitored voltage remaining constant is indicative of electrical contact. - View Dependent Claims (12)
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13. An apparatus for determining electrical contact between a semiconductor wafer and a wafer chuck, said apparatus comprising:
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a first capacitor plate proximate to said wafer; a second capacitor plate proximate to said wafer; a variable voltage source between said chuck and said first capacitor plate; and a voltage monitor between said second capacitor plate and said chuck, wherein a monitored voltage remaining constant is indicative of electrical contact. - View Dependent Claims (14)
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Specification