Preparation method for deep trench isolation channel

A technology of isolation grooves and deep grooves, which is applied in the manufacture of microstructure devices, techniques for producing decorative surface effects, decorative arts, etc., and can solve problems such as LPCVD polysilicon gaps and horseshoes

Inactive Publication Date: 2012-02-08
NORTHWESTERN POLYTECHNICAL UNIV
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

[0006] The purpose of the present invention is: in order to solve the problems such as gaps and horseshoe phenomenon in L

Method used

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  • Preparation method for deep trench isolation channel
  • Preparation method for deep trench isolation channel
  • Preparation method for deep trench isolation channel

Examples

Experimental program
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Effect test

Embodiment 1

[0029] refer to Figure 7 , in this embodiment, it is a resonator package, and the whole structure includes an SOI base layer 6 , an SOI oxide layer 7 , a structure 8 , a resonator 9 , a glass 10 and an SOI device layer 11 . Since the SOI device layer 11 and the peripheral shell are connected together, the shell is exposed to the outside and will be in contact with the human body or other conductive objects, and a voltage needs to be applied to the structure 8. If the structure layer 8 and the SOI device layer 11 are not insulated , will affect the electrical performance of the resonator 9, so it must be electrically insulated. Therefore, the structural body 8 and the SOI device layer 11 need to be mechanically connected and electrically insulated, which can be realized by using the deep trench isolation trench preparation method proposed by the present invention.

[0030] refer to Figure 1-6 , the preparation method of the deep trench isolation trench in this embodiment in...

Embodiment 2

[0039] refer to Figure 8 , this embodiment is a micro-torsion mirror. In the previous test of the micro-torsion mirror, after the anchor point connected to the mirror surface and the fixed anchor points at both ends of the mirror surface were applied with voltage, the rotation stability of the micro-torsion mirror was not high. In order to further improve the micro-torsion mirror The stability of the torsion mirror requires feedback control of the micro-torsion mirror. The method used is to divide the entire mirror into two through a deep trench isolation groove, which are the powered mirror and the isolated mirror. In order to ensure the rotation of the entire mirror , it is necessary to fill the deep trench with a layer of silicon dioxide insulating layer and polysilicon for mechanical connection. The energized mirror is connected to the movable comb and forms the drive end with the corresponding fixed comb, while the isolated mirror is also connected to the movable comb an...

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Abstract

The invention discloses a preparation method for a deep trench isolation channel, aiming at the requirements of mechanical connection but electrical insulation in MEMS (Micro Electro Mechanical System) technology. The method comprises the following steps of: polishing a silicon wafer; photo-etching; performing DRIE (Deep Reactive Ion Etching) to form a deep channel 2, wherein the deep channel 2 has an inverted isosceles trapezoid shape, and an included angle theta between a side wall of the channel and vertical direction is greater than or equal to 1 degree and is less than or equal to 5 degrees; cleaning with oxygen; generating a silicon dioxide insulating layer 3 on the surface of the side wall of the deep channel 2 and the surface of the silicon wafer; and filling a polycrystalline silicon layer 4. The preparation method has the beneficial effects that: the silicon wafer is etched into the inverted trapezoidal deep trench isolation channel by using DRIE; Notching phenomenon in isotropic etching is avoided; and the filling of the bottom of the deep channel can be guaranteed. Since the deep channel has the inverted trapezoid shape, an open part is still larger than the middle part of the channel, and the situation of a gap caused by blockage of the open part is also avoided during deposition of polycrystalline silicon. Since the included angle between the side wall of an oblique channel and the vertical direction is smaller, insulating characteristic and mechanical strength of the isolation channel are not influenced, and packaging air-tightness and insulation requirement can be met.

Description

[0001] Field: [0002] The present invention generally relates to microelectromechanical systems (MEMS) and micromachining techniques. Background technique: [0003] In MEMS technology, there are often scenarios that require mechanical connection but electrical isolation. The existing method is realized by a deep trench isolation trench with a rectangular cross section, and the deep trench isolation trench is filled with a sandwich material with silicon dioxide on both sides and polysilicon in the middle. However, since the etching ions will bounce back from the bottom surface during the etching process, resulting in secondary etching of the sidewall, it is easy to cause the opening to be smaller than the middle part of the trench. Experimental verification shows that this cross-section is a rectangular deep trench isolation. Grooves are prone to gaps during preparation. The preparation method of this deep trench isolation groove is widely used, can be used in the encapsulat...

Claims

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Application Information

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IPC IPC(8): B81C1/00
Inventor 李晓莹李光涛乔大勇任森张艳飞康宝鹏
Owner NORTHWESTERN POLYTECHNICAL UNIV
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