CN102642805B

CN102642805B - Method for preparing silicon carbide (SiC) micro-nano needle tips

Info

Publication number: CN102642805B
Application number: CN201210102560.9A
Authority: CN
Inventors: 张海霞; 唐伟; 孟博
Original assignee: Peking University
Current assignee: Peking University
Priority date: 2012-04-09
Filing date: 2012-04-09
Publication date: 2015-01-07
Anticipated expiration: 2032-04-09
Also published as: CN102642805A

Abstract

The invention discloses a method for preparing silicon carbide (SiC) micro-nano needle tips. The method comprises the following steps of: producing sags of inverted pyramid structures in the front face of a silicon wafer by using photoetching and wet etching of a standard semiconductor process, wherein the silicon wafer with the sags serves as a needle tip template; then growing a SiC thin film on the silicon wafer, and windowing to define SiC needle tips and cantilever structures; making grooved structures on the front face of a glass sheet by simultaneously using photoetching and wet etching (or dry etching); bonding graphic surfaces of the silicon wafer and the glass sheet together; and finally, etching to remove a Si substrate so as to release the SiC needle tips and the cantilever structures, thereby producing the SiC micro-nano needle tips.

Description

A kind of method preparing the micro-nano needle point of carborundum

Technical field

The present invention relates to a kind of traditional micro fabrication, particularly prepare the process technology of micro-nano carbon SiClx needle point.

Background technology

Growing along with nanometer technique, to relevant testing equipment, the required precision as scanning probe microscopy and AFM is also more and more higher.In such devices, test probe is certainly a very important part, and probe tip is thinner, and certainty of measurement is higher.How to process tapering, simultaneously wear-resisting again, not easily broken needle point is an important technology.At present conventional needle point is mainly with (T.S.Ralli and R.8.Marcus, Oxidation sharpening of silicon tips, J.Vac.Sci.Technol.B 9 (6), 1991, pp.2733-2737 prepared by silicon; Marcus, R.B., Ravi, T.S., Gmitter, T., Chin, K., Liu, D., Orvis, W.J., Ciarlo, D.R., Hunt, C.E., Trujillo, J., Formation of silicon tips with < 1nm radius, Appl.Phys.Lett.56 (3), 1989, pp.236-238; Randal J.Grow, Stephen C.Minne, Scott R.Manalis, Calvin F.Quate, Silicon Nitride CantileversWith Oxidation-Sharpened Silicon Tips for Atomic Force Microscopy, JMEMS, 2002, vol.11, pp.317-321.).But the mechanical performance of silicon needle point, as hardness, fracture strength etc. are all not ideal enough.And have the carborundum of the title of DLC, have excellent electricity, calorifics, chemistry and mechanical property, its device prepared or structure can well work in extreme environment, as severe corrosive, high temperature, high voltage, high pressure etc.Therefore, will be very good by the micro-nano needle point prepared with carbofrax material.But, just because of chemistry and the mechanical property of carbofrax material excellence, make the processing to it, comprise wet etching, etching etc. very difficult, therefore, there is technologic challenge with carbofrax material processing needle point.Before this, part researcher have employed chemical synthesis (Andreas Mavrandonakis, George E.Froudakis, Antonis Andriotis, Madhu Menon, Silicon carbide nanotube tips:Promising materials for atomic force microscopy and/or scanning tunneling microscopy, Applied Physics Letters, 2006, pp.), to silicon needle point ion implantation (Mark A Lantz, Bemd Gotsmann, Papot Jaroenapibal, Tevis D.B.Jacobs, Sean D.O ' Connor, Kumar Sridharan, and Robert W.Carpick) method prepare carborundum needle point, its manufacturing process is complicated, non-traditional micro fabrication.

Summary of the invention

The object of this invention is to provide one and utilize traditional micro fabrication, i.e. the traditional handicrafts such as photoetching, wet etching, chemical vapor deposition, bonding, prepare the method for the micro-nano needle point of carborundum.

To achieve these goals, photoetching in the present invention's standard semi-conductor processes and wet etching obtain the depression of inverted pyramid structure in the front of Si sheet, then utilize conventional deposition equipment to look unfamiliar grow SiC film at this, and windowing define SiC needle point and cantilever beam structure; Use photoetching and wet etching (or dry etching) to produce groove structure in the front of sheet glass simultaneously; Bonding apparatus is utilized to be bonded together by the picture surface of silicon chip and sheet glass; Si substrate is removed in final etching, discharges SiC needle point and cantilever beam structure, thus the obtained micro-nano needle point of carborundum.

Concrete, carborundum provided by the present invention micro-nano needle point preparation method is a kind of templet manufacturing method, comprises the following steps:

A, produced the masterplate of depression as needle point of inverted pyramid structure by photoetching and wet etching in the front of a silicon chip;

B, front deposit carborundum films in step a gained silicon chip;

C, form window by photoetching and etching silicon carbide film, define carborundum needle point and the shape of cantilever beam structure being connected needle point;

D, in the front of a sheet glass by photoetching and corrosion or etching make groove;

E, the groove of sheet glass aimed at carborundum needle point on silicon chip and cantilever beam structure, by anode linkage, silicon chip and sheet glass are bonded together;

F, by step e obtain bonding pad remove Si by wet etching, discharge needle point and cantilever beam structure, so far, just complete the processing of the micro-nano needle point of carborundum.

Above-mentioned steps a makes the depression of inverted pyramid structure by wet etching Si, and wherein corrosive liquid used is preferably the potassium hydroxide solution that mass concentration is 20 ~ 40%, etching time 5 ~ 500 minutes (being determined by the height of required needle point).

Above-mentioned steps b general using plasma chemical gas-phase deposition method depositing carbon SiClx, the carborundum films thickness of institute's deposit preferably in 100 nanometers to 10 microns.Concrete deposition conditions can be: pressure 700 ~ 1200mTorr; Temperature 200 ~ 400 DEG C; SiH ₄: 20 ~ 60sccm, CH ₄: 200 ~ 400sccm, Ar:200 ~ 400sccm; Each cycle H F (high frequency electric source) acts on 10 ~ 20s, and LF (low-frequency power) acts on 20 ~ 30s; Power 200 ~ 400W.Wherein the frequency of HF and LF is respectively 13.56MHz and 380kHz.

Etching described in above-mentioned steps c adopts inductively coupled plasma (ICP) etching.

The anode linkage condition of above-mentioned steps e can be: the pressure in bonding chamber is 1 ~ 0.001mbar, and temperature is 200 DEG C ~ 450 DEG C, and bonding pole plate applied pressure is 200 ~ 800mbar, and voltage is 300 ~ 900V, and bonding time is 3 ~ 15min.

The method of above-mentioned steps f wet etching Si be bonding pad is placed in mass concentration be 20 ~ 40% KOH solution corrode.

The present invention utilizes traditional micro fabrication to prepare the micro-nano needle point of carborundum, simple, and the alternative traditional silicon micro-nano needle point of the micro-nano needle point of prepared carborundum, is applied in scanning probe microscopy or AFM.

Accompanying drawing explanation

Fig. 1 is the process chart that the micro-nano needle point of carborundum of the present invention makes.

Fig. 2 is the inverted pyramid structure graphics of embodiment step 2 on silicon chip after deposit carborundum films.

Fig. 3 is the graphics of the micro-nano needle point of carborundum that embodiment is finally prepared.

Detailed description of the invention

Below in conjunction with accompanying drawing, by specific embodiment, the invention will be further described, but the scope do not limited the present invention in any way.

As shown in Figure 1, the technological process of carborundum micro-nano needle point making is as follows:

1, twin polishing is adopted, resistivity 2 ~ 4 Ω-cm, crystal orientation <100>, the N-type silicon chip that thickness is 400 μm, photoetching, be that mask carries out wet etching with photoresist, corrosive liquid used to be mass concentration be 30% potassium hydroxide solution, etching time is 10 minutes.The depression 2 of inverted pyramid structure is made, as shown in Fig. 1 (a) in the front of silicon chip 1.

2, in the front of silicon chip 1 with plasma chemical vapor deposition equipment (PECVD) growing silicon carbide film 3, thickness is 1 micron, and as shown in Fig. 1 (b), its stereogram is shown in Fig. 2.

Wherein, the condition of PECVD deposit SiC film is: pressure 700 ~ 1200mTorr; Temperature 200 ~ 400 DEG C; SiH ₄: 20 ~ 60sccm, CH ₄: 200 ~ 400sccm, Ar:200 ~ 400sccm; Each cycle H F (high frequency electric source): 10 ~ 20 ", LF (low-frequency power): 20 ~ 30 "; Power 200 ~ 400W.Wherein the frequency of HF and LF is respectively 13.56MHz and 380kHz.

3, in front side of silicon wafer photoetching, inductively coupled plasma (ICP) etching SiC 3, defines window 4, as shown in Fig. 1 (c).

4, sheet glass 5 front photoetching and etch (or corrosion), preparation vessel 6, as shown in Fig. 1 (d);

5, the front side of silicon wafer phase para-linkage that sheet glass above-mentioned steps 4 obtained with anode linkage and step 3 obtain, as shown in Fig. 1 (e).

Wherein, taking carborundum films as the silex glass anode linkage condition of medium is: the pressure in bonding chamber is 1 ~ 0.001mbar, and temperature is 200 DEG C ~ 450 DEG C, and bonding pole plate applied pressure is 200 ~ 800mbar, voltage is 300 ~ 900V, and bonding time is 3 ~ 15min.

6, the silex glass sheet after bonding is placed in the KOH solution of 30%, removes silicon substrate, release needle point and cantilever beam structure, thus obtain the micro-nano needle point 7 of carborundum, as shown in Fig. 1 (f), its stereogram is shown in Fig. 3.

Claims

1. prepare a method for the micro-nano needle point of carborundum, comprise the following steps:

B, front using plasma chemical gas-phase deposition method deposit carborundum films in step a gained silicon chip, deposition conditions is: pressure 700 ~ 1200mTorr; Temperature 200 ~ 400 DEG C; SiH ₄: 20 ~ 60sccm, CH ₄: 200 ~ 400sccm, Ar:200 ~ 400sccm; Each cycle high frequency electric source effect 10 ~ 20s, low-frequency power effect 20 ~ 30s; Power 200 ~ 400W;

E, the groove of sheet glass aimed at carborundum needle point on silicon chip and cantilever beam structure, by anode linkage, silicon chip and sheet glass are bonded together, the condition of anode linkage is: the pressure in bonding chamber is 0.001 ~ 1mbar, temperature is 200 DEG C ~ 450 DEG C, bonding pole plate applied pressure is 200 ~ 800mbar, voltage is 300 ~ 900V, and bonding time is 3 ~ 15min;

F, by step e obtain bonding pad remove silicon chip by wet etching, discharge needle point and cantilever beam structure.

2. the method for claim 1, is characterized in that, in step a wet etching corrosive liquid used to be mass concentration be 20 ~ 40% potassium hydroxide solution.

3. the method for claim 1, is characterized in that, in step a, the etching time of wet etching is 5 ~ 500 minutes.

4. the method for claim 1, is characterized in that, the carborundum films thickness of step b institute deposit is 100 nanometer ~ 10 micron.

5. the method for claim 1, is characterized in that, step c adopts sense coupling technology etching silicon carbide film.

6. the method for claim 1, is characterized in that, the method for step f wet etching silicon chip be bonding pad is placed in mass concentration be 20 ~ 40% KOH solution corrode.