CN101602480A

CN101602480A - The method of etching silicon pulse sensor socle beam by laser

Info

Publication number: CN101602480A
Application number: CNA2008100646935A
Authority: CN
Inventors: 温殿忠; 王璐
Original assignee: Heilongjiang University
Current assignee: Heilongjiang University
Priority date: 2008-06-11
Filing date: 2008-06-11
Publication date: 2009-12-16

Abstract

The present invention relates to a kind of method, especially this method that adopts laser to discharge silicon cantilever and be the combine method of etch silicon cantilever beam of laser processing technology and microelectron-mechanical system of processing (MEMS).The invention provides a kind of method that adopts laser precisely to discharge silicon cantilever, this method can not only discharge the silicon cantilever of no top rake, and provides high-quality laser etching method for the preparation of other micro-structurals.The process program that manufacture method of the present invention adopted is: on silicon chip, adopt the MEMS technology to make the Wheatstone bridge of forming by four P-channel enhancement type FETs (P-MOSFETs) at the root of silicon micro-cantilever, utilize inductively coupled plasma (ICP) lithographic technique to be processed into structure of silicon cup the silicon chip back silicon substrate, and go out silicon cantilever with laser ablation.The invention has the beneficial effects as follows, overcome the top rake problem of traditional release silicon cantilever method, need not photoetching development, the etch rate height.

Description

The method of etching silicon pulse sensor socle beam by laser

Technical field

The present invention relates to a kind of method that adopts etching silicon pulse sensor socle beam by laser, especially this method is the combine method of etch silicon cantilever beam of laser processing technology and microelectron-mechanical system of processing (MEMS).

Background technology

At present, to provide the method for known release silicon cantilever be to adopt wet method or dry etching to some reports in " Sensors and Actuators " and the magazines such as " semiconductor journals ", and silicon cup is carried out anisotropic etch or isotropic etch.Research institution is in MEMS technology both at home and abroad, and what often adopt is wet etching liquid such as KOH, hydrazine and aqueous corrosion liquid, TMAH corrosive liquid and EPW.But, because the ablation of fast erosional surface can the top rake phenomenon occur at the salient angle place.For example, when (100) silicon chip carries out anisotropic etch release silicon micro-cantilever in the EPW corrosive liquid, because of the higher crystal face of some corrosion rates appears in the salient angle place of intersecting in silicon chip (111) side, make the silicon under the silicon cantilever salient angle mask be subjected to sideetching, very serious silicon cantilever salient angle top rake phenomenon appears, the effective area of beam reduces, and can't obtain complete silicon cantilever structure, has a strong impact on the quality and the performance of silicon cantilever.Both at home and abroad the present main goal in research of research institution be limited to additional square on the salient angle of silicon cantilever structure, rectangle, triangle,＜110〉bar shaped,＜different mask patterns such as 100〉bar shaped, realization is to the compensation of top rake, the acquisition complete lobe formation of trying one's best, but various compensation methodes all exist deficiency and limitation, can't obtain that structure is accurate, the measured silicon cantilever of matter.

Summary of the invention

There is salient angle top rake phenomenon in order to overcome existing release silicon cantilever method, can't obtain the deficiency of complete cantilever beam structures, the invention provides a kind of method that adopts laser processing technology precisely to discharge silicon cantilever, this method can not only discharge the silicon cantilever of no top rake phenomenon, and provides high-quality laser etching method for the preparation of other micro-structurals.

The process program that manufacture method of the present invention adopted is: on silicon chip, adopt the MEMS technology to make the Wheatstone bridge of forming by four P-channel enhancement type FETs (P-MOSFETs) at the root of silicon micro-cantilever, utilize inductively coupled plasma (ICP) lithographic technique or silicon anisotropic etching technology to be processed into structure of silicon cup the silicon chip back silicon substrate, utilize laser processing technology again, etch silicon cantilever.

The invention has the beneficial effects as follows, can overcome the top rake problem that occurs in traditional release silicon cantilever method, the cantilever beam figure of making is regular rectangular shape, and adopt the silicon cantilever surface smoothness of this method etching good, the perpendicularity height, size is accurate, the etch rate height, have the superiority that does not need photoetching development just can carry out figure processing, also provide a kind of new method with other micro-structural for the preparation micro-cantilever.

Description of drawings

The present invention is further described below in conjunction with drawings and Examples.

Fig. 1 is a process principle figure of the present invention.

Fig. 2 is the silicon micro cantilever structure pulse image sensor figure that first embodiment of the present invention makes.

Fig. 3 is the vertical view of Fig. 2.

Fig. 4 is that a P-MOSFET with silicon micro-cantilever root among Fig. 1 is an example, provides silicon micro cantilever structure pulse image sensor profile.

Fig. 5 is four Wheatstone bridges that P-MOSFETs forms among Fig. 2.

Fig. 6 is that a P-MOSFET with silicon micro-cantilever root among Fig. 2 is an example, provides the technological process profile.

Fig. 7 is laser ablation cantilever beam system figure.

In Fig. 2, the 1. Wheatstone bridge that constitutes by four P-channel enhancement type FETs (P-MOSFETs), 2. silicon cantilever, 3. silicon materials, 4.SiO ₂Material.

In Fig. 7,5. computer and control system, 6. laser system, 7. laser beam, 8. substrate of glass, 9. loading workbench.

The specific embodiment

In the embodiment shown in Figure 2, the material of selecting for use is that the resistivity of twin polishing is N type (100) the crystal orientation silicon chip 3 of 100 Ω cm, after adopting the conventional silicon chip cleaning of IC that the silicon chip of selecting for use is cleaned, put the high-temperature oxydation stove into and carry out two-sided oxidation, formation has certain thickness silicon dioxide layer 4, the silicon chip upper surface is carried out a photoetching, make P by lithography ^-The doped region window adopts ion implantation technique to form P ^-Doped region adopts the method for dried oxygen-wet oxygen-dried oxygen to carry out secondary oxidation, and the deposit polysilicon, forms the grid of metal-oxide-semiconductor field effect transistor, and secondary photoetching then carves the substrate window, utilizes ion implantation technology to form N ⁺The district carries out three oxidations and third photo etching again and forms source ornamental perforated window mouth, and adopts ion implantation technology formation source to leak P ⁺The district, then carry out four oxidations, four photoetching, carve the fairlead zone, the AM aluminum metallization electrode anti-carves aluminium again, forms the Wheatstone bridge 1 that is made of four P-MOSFETs, then the silicon chip for preparing is put into and be warmed to 410 ℃ in the high temperature furnace and carried out alloying in ten minutes, to guarantee forming Ohmic contact between aluminium, the silicon.Then, utilize the ICP lithographic technique that the good silicon chip of photoetching is carried out plasma etching or anisotropic etch, make the silicon cup window by lithography in silicon chip back.At last, utilize laser engraving machine to etch silicon cantilever 2.Laser system 6 is controlled automatically by computer 5, silicon cup and substrate of glass 8 are fixed on the loading workbench 9 together, on silicon cup, find the datum mark coordinate, in the mark operating system of computer, structure in conjunction with the silicon cantilever of silicon cup and expection, the shape and size of design laser ablation, parameters such as setting laser power and mark number of times utilize laser beam 7 to etch silicon cantilever 2.

Claims

1. process that adopts laser to discharge silicon cantilever, it is characterized in that: on silicon chip, adopt the MEMS technology to make the Wheatstone bridge of forming by four P-channel enhancement type FETs (P-MOSFETs) at the root of silicon micro-cantilever, utilize inductively coupled plasma (ICP) lithographic technique or anisotropic corrosion technique to be processed into structure of silicon cup the silicon chip back silicon substrate, utilize laser processing technology again, etch silicon cantilever.

2. process according to claim 1, utilize the MEMS technology to be processed into structure of silicon cup the silicon chip back silicon substrate, both can adopt dry etching, and also can adopt the corrosion of wet method deep trouth, the figure of institute's etching can be the figure that multiple computer can design.