Deep Si etching method

A deep silicon etching and surface etching technology, applied in decorative arts, gaseous chemical plating, microstructure technology, etc., can solve the problems of reduced etching rate, sidewall damage, increased line width loss, etc.

Active Publication Date: 2018-08-03
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the deep etching system, there is a problem that the etching rate decreases as the width of the etching groove becomes narrower. This phenomenon is called the lag effect. Sometimes even in the etching of a narrow etching groove, the etching rate gradually decreases with the increase of

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0074] Embodiment 1 prepares the base material that covers patterned mask layer on the silicon wafer

[0075] Step 1: Prepare Silicon Wafer Material

[0076] The specifications of the prepared silicon wafer are N-type 100 crystal orientation, thickness 400um, resistivity 0.002-0.005Ω·m. And use a laser marking machine to mark and number the silicon wafers (the marking side is the back side, and the non-marking side is the front side) for subsequent data recording.

[0077] Step Two: Clean the Wafer

[0078] Silicon wafers are cleaned with standard RCA before use. Put the glass sheet in the mixed solution of sulfuric acid:hydrogen peroxide=4:1 and wash it for 5 minutes, and rinse it with deionized water for 5 times; Rinse with deionized water for 5 times; then wash in a mixed solution of hydrochloric acid: hydrogen peroxide: deionized water = 1:1:4 for 5 minutes, rinse with deionized water for 5 times; dry at 2000 rpm for 5 minutes.

[0079] Step 3: Preparation of SiO 2 ha...

Embodiment 2

[0085] Embodiment 2 deep silicon etching process

[0086] Using equipment SPTS LPX ICP-SR, using the process parameters shown in Table 1, the substrate provided in Example 1 was etched on silicon wafers.

[0087] Table 1 Parameter table of deep silicon etching process

[0088]

[0089] The deep silicon etching process was carried out 920 cycles in total, and the passivation time of the passivation step increased at a uniform speed with the increase of the number of cycles, and the rate of increase was 2.17×10 -4 s / period, increased from 2.2s to 2.4s; the etching time of the second etching step increases at a uniform speed as the number of cycles increases, and the rate of increase is 2.06×10 -3 s / period, increased from 0.8s to 2.7s; the electric plate plate power of the second etching step increases at a uniform speed with the increase of the number of cycles, and the increase rate is 1.09×10 -2 W / cycle, increased from 50W to 60W; the gas pressure of the second etching st...

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Abstract

The present invention discloses a deep Si etching method. The method comprises the steps of: providing a silicon wafer coated with a graphical mask layer, and etching the surface of the silicon waferwithout being coated with the mask layer to form an etching surface and a side wall basically perpendicular to the etching surface. The method further comprises repeated and circulated passivation step, first etching step and second etching step until a predetermined etching depth is obtained. With the increasing of the number of times of cycle periods, at least one of conditions (1)-(3) is met that: (1) the deposition time of the passivation step is increased with the increasing of the number of times of the cycle periods, (2) the plate electrode power in the second etching step is increasedwith the increasing of the number of times of the cycle periods, and (3) the air pressure in the second etching step is increased with the increasing of the number of times of the cycle periods.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a deep silicon etching method. Background technique [0002] Micro-electromechanical system sensors are more and more widely used in the fields of automobiles, mobile phones and smart wearable devices, and micro-electromechanical system (MEMS) technology with bulk silicon technology as the core is developing particularly rapidly. The development of high aspect ratio silicon etching technology has greatly improved the sensitivity of micro sensors and actuators. Compared with the surface silicon process, the bulk silicon process with the deep silicon etching process as the core can obtain a larger detection capacitance and a more sensitive mass structure, which improves the resolution and sensitivity of the MEMS sensor. [0003] The current deep silicon etching system is realized by Bosch process. In the deep etching system, there is a problem that the etching rate decr...

Claims

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Application Information

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IPC IPC(8): H01L21/3065B81C1/00
CPCB81C1/00531H01L21/30655
Inventor 阮勇尤政崔志超
Owner TSINGHUA UNIV
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