Chemical mechanical polishing method for silicon substrate

Abstract

The invention discloses a chemical mechanical polishing method for a silicon substrate. The chemical mechanical polishing method comprises the steps that activating treatment is conducted on a polishing pad through a polishing solution containing abrasive particles, the activating treatment comprises pre-polishing treatment, and the pre-polishing treatment refers to polishing conducted on the polishing pad through the polishing solution containing the abrasive particles; and a to-be-machined workpiece is placed above the activated polishing pad, and the surface of the to-be-machined workpiece is polished through a polishing solution without abrasive particles. By means of the chemical mechanical polishing method for the silicon substrate, the processing process steps of the silicon substrate are greatly simplified, the use of the abrasive particles such as silica sol is reduced, and the research and development cost and the investment of production equipment are reduced; under the condition that the relatively high cutting rate is kept, polishing materials are saved, and personnel and the environment are protected; and compared with an existing mature process, the method is not greatly changed, the existing mature process can be conveniently replaced with the chemical mechanical polishing method, and the chemical mechanical polishing method has great application prospects.

Description

technical field

[0001] The invention belongs to the technical field of semiconductor processing, and relates to a novel silicon substrate chemical mechanical polishing method, in particular to a processing method which greatly simplifies the process and can obtain a silicon substrate surface with a higher cutting rate without abrasives. Background technique

[0002] Chemical mechanical polishing is an important technology in the manufacturing process of semiconductor devices. It uses chemical corrosion and mechanical force to planarize silicon wafers or other substrate materials during processing. Chemical mechanical polishing technology is used in various semiconductor wafers. Widely used in manufacturing. At present, chemical mechanical polishing mainly has the following two approaches: 1) use polishing fluid+polyurethane polishing pads or similar products containing abrasive particles such as silica sol, aluminum oxide, cerium oxide or composite abrasives for polishing, b...

Examples

Embodiment 1

[0028] A method for chemical mechanical polishing of a silicon substrate, the steps of which are as follows:

[0029] (1) Preparation of polishing fluid containing abrasive particles:

[0030] Weigh 50 g of silica sol with a particle size of 130 nm and a solid content of 40%, add deionized water to prepare a silica sol polishing solution with a mass fraction of 2 wt %;

[0031] (2) Place the silicon substrate above the suba 800 polishing pad, use the sainko polishing equipment to rotate the polishing pad, set the speed of the grinding disc to 50rpm, and set the speed of the polishing head to 50rpm, and add the prepared mass fraction of 2wt% silica sol Polishing liquid, its flow rate is 100ml / min, carries out the preprocessing of silicon substrate surface, processing pressure 129g / cm 2 , the polishing time is 10min;

[0032] (3) After polishing, take out the silicon wafer for cleaning and weighing records, and then thoroughly clean the suba 800 polishing pad. At this time, th...

Embodiment 2

[0040]A method for chemical mechanical polishing of a silicon substrate, which is substantially the same as in Example 1, except that the polishing liquid containing no abrasive particles is an aqueous solution of sodium silicate with a modulus of 3.3 of 0.025M at a concentration of 1000 g, and the surface of the silicon substrate is chemical mechanical polishing, the pressure is 129g / cm 2 , at this time the chemical mechanical polishing efficiency reaches 52.3nm / min, change the pressure to 183g / cm 2 , the cutting rate increased to 89.3nm / min; the pressure was 239g / cm 2 , the cutting rate is 128.8nm / min (the cutting rate will increase with the increase of pressure).

Embodiment 3

[0044] A chemical mechanical polishing method for a silicon substrate, which is substantially the same as in Example 1, except that a black damping cloth is used to replace the suba 800 polishing pad, and the polishing liquid not containing abrasive particles is 1000g concentration of silicon with a modulus of 3.3 of 0.025M Potassium acid aqueous solution, chemical mechanical polishing of the surface of the silicon substrate, the pressure is 238g / cm 2 , the cutting rate is 28.3nm / min.

technical field

[0001] The invention belongs to the technical field of semiconductor processing, and relates to a novel silicon substrate chemical mechanical polishing method, in particular to a processing method which greatly simplifies the process and can obtain a silicon substrate surface with a higher cutting rate without abrasives. Background technique

[0002] Chemical mechanical polishing is an important technology in the manufacturing process of semiconductor devices. It uses chemical corrosion and mechanical force to planarize silicon wafers or other substrate materials during processing. Chemical mechanical polishing technology is used in various semiconductor wafers. Widely used in manufacturing. At present, chemical mechanical polishing mainly has the following two approaches: 1) use polishing fluid+polyurethane polishing pads or similar products containing abrasive particles such as silica sol, aluminum oxide, cerium oxide or composite abrasives for polishing, b...

Examples

Embodiment 1

[0028] A method for chemical mechanical polishing of a silicon substrate, the steps of which are as follows:

[0029] (1) Preparation of polishing fluid containing abrasive particles:

[0030] Weigh 50 g of silica sol with a particle size of 130 nm and a solid content of 40%, add deionized water to prepare a silica sol polishing solution with a mass fraction of 2 wt %;

[0031] (2) Place the silicon substrate above the suba 800 polishing pad, use the sainko polishing equipment to rotate the polishing pad, set the speed of the grinding disc to 50rpm, and set the speed of the polishing head to 50rpm, and add the prepared mass fraction of 2wt% silica sol Polishing liquid, its flow rate is 100ml / min, carries out the preprocessing of silicon substrate surface, processing pressure 129g / cm 2 , the polishing time is 10min;

[0032] (3) After polishing, take out the silicon wafer for cleaning and weighing records, and then thoroughly clean the suba 800 polishing pad. At this time, th...

Embodiment 2

[0040]A method for chemical mechanical polishing of a silicon substrate, which is substantially the same as in Example 1, except that the polishing liquid containing no abrasive particles is an aqueous solution of sodium silicate with a modulus of 3.3 of 0.025M at a concentration of 1000 g, and the surface of the silicon substrate is chemical mechanical polishing, the pressure is 129g / cm 2 , at this time the chemical mechanical polishing efficiency reaches 52.3nm / min, change the pressure to 183g / cm 2 , the cutting rate increased to 89.3nm / min; the pressure was 239g / cm 2 , the cutting rate is 128.8nm / min (the cutting rate will increase with the increase of pressure).

Embodiment 3

[0044] A chemical mechanical polishing method for a silicon substrate, which is substantially the same as in Example 1, except that a black damping cloth is used to replace the suba 800 polishing pad, and the polishing liquid not containing abrasive particles is 1000g concentration of silicon with a modulus of 3.3 of 0.025M Potassium acid aqueous solution, chemical mechanical polishing of the surface of the silicon substrate, the pressure is 238g / cm 2 , the cutting rate is 28.3nm / min.