Method for grinding semiconductor wafers
View Patent ↗Semiconductor wafers are processed so as to remove material on one or both sides by means of at least one grinding tool, with coolant supplied into a contact region between the semiconductor wafer and the at least one grinding tool, characterized in that the coolant flow rate is set as a function of a grinding tooth height of the at least one grinding tool and this coolant flow rate is reduced as the grinding tooth height decreases.
1. A method for the grinding of semiconductor wafers to remove material from at least one side thereof, comprising:
grinding a slide of a semiconductor wafer with a grinding tool having grinding teeth with a grinding tooth height;
supplying a coolant into a contact region between the side of the semiconductor wafer and the grinding tool;
establishing a first coolant flow rate as a function of tooth height of the grinding teeth of the grinding tool;
measuring the tooth height of the grinding teeth reduced in height by grinding to provide a measured tooth height; and
reducing the coolant flow rate to a subsequent coolant flow rate as the measured tooth height decreases.
2. The method of claim 1 , wherein a single-sided grinding machine is used and the semiconductor wafer is ground on one side by means of a grinding tool.
3. The method of claim 1 , wherein a double-sided grinding machine is used and the semiconductor wafer is ground simultaneously on both sides by means of two grinding tools.
4. The method of claim 3 , wherein the coolant flow rate does not fall below a preset minimum value.
5. The method of claim 4 , wherein the preset minimum value is a coolant flow rate which prevents aquaplaning.
6. The method of claim 3 , wherein a grinding tool with ceramically bound diamond grinding teeth is used as the grinding tool.
7. The method of claims 3 , wherein a current grinding tooth height is measured for both grinding tools after each individual wafer has been ground, setpoint values of the coolant flow are determined for those grinding tooth heights and a setpoint value of coolant flow is adjusted separately for each of the two grinding tools.
8. The method of claims 1 , wherein a coolant flow rate is initially selected as said first coolant flow rate when using a fresh grinding tool, a current grinding tooth height of the grinding tool is measured during grinding processes, and the coolant flow rate is reduced as a function of the measured tooth height.
9. The method of claim 8 , wherein a grinding tool with ceramically bound diamond grinding teeth is used as the grinding tool.
10. The method of claim 8 , wherein the current grinding tooth height is measured after a grinding operation and before a subsequent grinding operation.
11. The method of claim 8 , wherein the coolant flow rate does not fall below a preset minimum value.
12. The method of claim 11 , wherein the preset minimum value is a coolant flow rate which prevents aquaplaning.
13. The method of claim 1 , wherein a grinding tool with ceramically bound diamond grinding teeth is used as the grinding tool.
14. The method of claim 3 , wherein a setpoint value of the coolant flow rate is determined electronically as a function of the grinding tooth height by means of software, and is adjusted by means of an actuator or pressure reducer.
15. The method of claim 14 , wherein the setpoint value of the coolant flow is determined by means of the software from a parameterizable profile comprising a plurality of sample points and dependent on the tooth height, the sample points representing a coolant flow rate for a previously determined grinding tooth height.