CN100435285C

CN100435285C - A method for preparing the nano-electrode with the negative electronic erosion-resisting agent

Info

Publication number: CN100435285C
Application number: CNB2006100035311A
Authority: CN
Inventors: 龙世兵; 刘明; 陈宝钦
Original assignee: Institute of Microelectronics of CAS
Current assignee: Institute of Microelectronics of CAS
Priority date: 2006-02-09
Filing date: 2006-02-09
Publication date: 2008-11-19
Anticipated expiration: 2026-02-09
Also published as: CN101017778A

Abstract

The preparation method for nano electrode comprises: growing well-conductive metal or semiconductor layer; using EBL to obtain a couple or group negative electronic anti-corrosive agent, and coating the agent; first baking; with electron beam to direct expose; developing, fixing, etching, and stripping the photoresist. The product has 20-100nm space and fit to wide application. This invention is simple and reliable, and compatible with traditional CMOS technology.

Description

A kind of method for preparing nano-electrode with negative electronic erosion-resisting agent

Technical field

The invention belongs to technical field of nano-processing, particularly a kind of preparation method of nano-electrode.

Background technology

Since over half a century, be that the semiconductor integrated circuit of mainstream technology is being followed " Moore's Law " always and developed rapidly with CMOS, its characteristic size has entered into nanoscale, but also be faced with simultaneously more and more serious challenge, therefore become the focus of research based on the nano electron device of new material, new principle such as various quantum dot device, nano wire, nanometer tube device, single-electron device etc.In the making of these nano electron devices, size is little, good conductivity, making with the nano-electrode in nanometer scale gap are keys, also is a difficult point.

Application number is that 200410095163.9 Chinese invention patent mainly adopts chemical method to prepare electrode in conjunction with the utilization of macromolecular material, but kind electrode does not reach nanoscale.Application number is that 200410010181.2 Chinese invention patent prepares silver-colored nano-electrode with atomic force microscope (AFM) etching nanowire-junction combination method, has low, the shortcoming that can not large-scale production of efficient.Application number is that 99116576.4 Chinese invention patent adopts flame fusion and etching method to prepare class carbon fibre electrode, and electrode material is single, and only is used for biological field.Optical lithography is because its high efficiency is the mainstream technology of making electrode at present, but the resolution of optical lithography is subjected to the restriction of exposure wavelength to be difficult to reach nanometer resolution.Electron beam lithography is because the electron beam wavelength is very short, and diffraction effect can be ignored substantially, has very high resolution, and the resolution of high performance electronic bundle mask aligner can reach several nanometers.Therefore, adopt growth conductive film material, e-beam direct write lithography, etching technics, can prepare the nano-electrode of various spacings less than 100nm.This method has that processing step is few, simple, reliable and stable, purposes is many, can with the advantage of traditional cmos process compatibility.

Summary of the invention

The object of the present invention is to provide a kind of method for preparing spacing less than the nano-electrode of 100nm.

To achieve these goals, the present invention adopts electron beam lithography, and it is a kind of effective nanoprocessing means, has nano level resolution.The present invention mainly utilizes negative electronic erosion-resisting agent to carry out e-beam direct-writing exposure, on conductive film, form spacing less than a pair of of 100nm or one group of protruding upright electrode pattern of negative electronic erosion-resisting agent, can prepare nano-electrode through etching again with different shapes such as lines, square, circles.

A kind of employing negative electronic erosion-resisting agent, it is as follows to utilize electron beam lithography (EBL) and etching technics to prepare the concrete processing step of nano-electrode:

(1) conductive layer of on substrate, growing;

(2) the high explanation of coating negative electronic erosion-resisting agent;

(3) negative electronic erosion-resisting agent is carried out preceding baking;

(4) negative electronic erosion-resisting agent is carried out e-beam direct-writing exposure;

(5) develop, remove the electronic corrosion-resistant of unexposed area;

(6) photographic fixing;

(7) etching is transferred to electrode pattern on the conductive layer from resist;

(8) remove photoresist.

Wherein the substrate described in the step (1) is smooth, clean dielectric substrate such as SiO ₂, Si ₃N ₄, Al ₂O ₃, MgO, CaO etc., or the Semiconductor substrate of high-impedance state such as Si, Ge, GaAs, GaN, GaSb, GaP, AlAs, InAs, InP, InSb, SiC, ZnO, ZnS, CdS, CdTe, diamond etc.; Described conductive layer can adopt metal material such as Au, Ag, Pt, Al, W, Ti, Cr etc., transparent material such as ITO etc., the semi-conducting material of good conductivity is as highly doped, the Si of high conductivity, Ge, GaAs, AlAs, InAs, InP, SiC, ZnO, ZnS, CdS etc., these conductive layers can be monocrystalline or polycrystalline attitude, can be the single or multiple lift structure, can adopt any one growth in the following method: evaporation (high temperature evaporation, electron beam evaporation), sputter (radio frequency sputtering, magnetron sputtering), chemical vapour deposition (CVD) (CVD, PECVD, LPCVD, APCVD, MOCVD), extension (LPE, MBE), strengthen chemical vapour deposition (CVD) (PECVD), low-pressure chemical vapor deposition (LPCVD), aumospheric pressure cvd (APCVD), metal-organic chemical vapor deposition equipment (MOCVD), liquid phase epitaxy (LPE), molecular beam epitaxy (MBE) method.

Wherein the negative electronic erosion-resisting agent described in the step (2) can adopt SAL601, HSQ, Calixarene etc.Also need between (4) step and (5) step, to take baking step in back when adopting this chemistry of SAL601 to amplify resist.

Wherein the e-beam direct-writing exposure described in the step (4) can adopt JEOL JBX-5000LS electron-beam lithography system, and accelerating voltage is 50KeV, and electronic beam current is less than 100pA.

Wherein the etching described in the step (7) can adopt lithographic methods such as reactive ion etching (RIE), inductively coupled plasma (ICP) etching, electron cyclotron resonace (ECR) etching.

Wherein removing photoresist described in the step (8) can adopt special use to remove photoresist liquid removes photoresist, RIE dry method oxygen plasma removes photoresist, wet method is removed photoresist (as being dense H with the #3 cleaning fluid ₂SO ₄+ H ₂O ₂Boil glue) etc. the method for removing photoresist.

Description of drawings

Fig. 1-Fig. 5 is a process chart of the present invention;

Fig. 6-Figure 10 is the process chart of specific embodiment;

Figure 11 and Figure 12 are scanning electron microscopy (SEM) surface picture of heavily doped silicon nano-electrode.

Embodiment

In order to illustrate further content of the present invention, by description, further describe concrete grammar of the present invention below in conjunction with accompanying drawing to specific embodiment, wherein:

As shown in Figure 1, at smooth, clean dielectric substrate such as SiO ₂, Si ₃N ₄, Al ₂OO ₃MgO, CaO etc., or the Semiconductor substrate of high-impedance state such as Si, Ge, GaAs, GaN, GaSb, GaP, AlAs, InAs, InP, InSb, SiC, ZnO, ZnS, CdS, CdTe, adopt evaporation on the substrates such as diamond 1, sputter, chemical vapour deposition (CVD) (CVD, PECVD, LPCVD, APCVD, MOCVD), extension (LPE, the method various monocrystalline of growing such as MBE), polycrystalline or noncrystal conductive layer 2 are as Au, Ag, Pt, Al, W, Ti, metal materials such as Cr, transparent materials such as ITO, highly doped, the Si of high conductivity, Ge, GaAs, AlAs, InAs, InP, SiC, ZnO, ZnS, semi-conducting materials such as CdS.Perhaps directly adopt the surface to have the dielectric substrate 1 of above-mentioned conductive layer 2.

As shown in Figure 2, on conductive layer, apply high-resolution negative electronic erosion-resisting agent 3, as SAL601, HSQ, Calixarene etc. with sol evenning machine.Adopt baking oven or hot plate to carry out the preceding baking of certain hour and uniform temperature to the good electronic corrosion-resistant 3 of above-mentioned coating then.

As shown in Figure 3, e-beam direct-writing exposure is carried out in the

zone

4,5,6 of negative resist 3.The JBX-5000LS electron-beam lithography system that electron beam exposure can adopt JEOL company to produce, its accelerating voltage is 50KeV, electronic beam current is less than 100pA.Then the negative resist that exposed is developed and photographic fixing, remove the electronic corrosion-resistant of unexposed area, be formed for the

Etching mask

4,5,6 of etching.By technology controlling and process, the interval in development rear region 4 and zone 5, zone 5 and zone 6 be spaced apart 20-100nm.

As shown in Figure 4, negative electronic erosion-resisting

agent

4,5,6 after utilization is developed is as mask, adopt method etching conductive layers 2 such as reactive ion etching (RIE), inductively coupled plasma (ICP) etching, electron cyclotron resonace (ECR) etching, form required nano-

electrode

7,8,9.

As shown in Figure 5, liquid removes photoresist, RIE dry method oxygen plasma removes photoresist, wet method is removed photoresist (as being dense H with the #3 cleaning fluid to adopt special use to remove photoresist ₂SO ₄+ H ₂O ₂Boil glue) etc. the method for removing photoresist remove negative electronic erosion-resisting

agent

4,5,6 on the nano-

electrode

7,8,9, the interval of finishing in the conductive layer 2 on substrate 1 only is the preparation of the nano-

electrode

7,8,9 of 20-100nm.

Specific embodiment

To use SOI substrate, SAL601 chemical amplification negative electronic corrosion-resistant, ICP etching to be example, further specify detailed process method of the present invention and step in conjunction with the accompanying drawings below, wherein:

As shown in Figure 6, adopt the SOI substrate in p type, (111) crystal orientation, this SOI substrate is made of for 3 three layers silicon base 1, the thick top layer silicon of oxygen buried layer 2,50nm that 375nm is thick from top to bottom successively.Top layer silicon 3 to this SOI substrate is injected P ³¹⁺Ion, the injection energy is 20keV, implantation dosage is 1 * 10 ¹⁵Cm ^-2, then at N ₂In the atmosphere, 1200 ℃ of following short annealings 10 seconds, improve the conductivity of top layer silicon 3.

As shown in Figure 7, with sol evenning machine coating SAL601 chemical amplification negative electronic corrosion-resistant 4, the coating rotating speed is 3000rpm on above-mentioned SOI substrate, and the coating time is 60 seconds.Then with baking before hot plate is under 110 ℃ 3 minutes.

As shown in Figure 8, e-beam direct-writing exposure is carried out in the

zone

5,6 of negative resist 4.The JBX-5000LS electron-beam lithography system that electron beam exposure adopts JEOL company to produce, its accelerating voltage is 50KeV, and electronic beam current is 60pA, and exposure dose is 17-24 μ C/cm ²Then to the negative resist that exposed with hot plate 110 ℃ of back bakings 3 minutes down, and use MF CD-26 developing liquid developing 8 minutes immediately, remove the electronic corrosion-resistant of unexposed area, water photographic fixing immediately then is formed for the

Etching mask

5,6 of etching.Figure 11 is scanning electron microscopy (SEM) surface picture of the SAL601 negative electronic erosion-resisting agent mask for preparing on the SOI substrate, and the minimum spacing of resist nano-electrode figure is 80nm among the figure.

As shown in Figure 9, the negative electronic erosion-resisting

agent

5,6 after utilization is developed adopts the top layer silicon 3 of high density inductively coupled plasma (ICP) etching SOI substrate as mask, forms required nano-

electrode

7,8.

As shown in figure 10, be dense H with 120 ℃ #3 cleaning fluid ₂SO ₄+ H ₂O ₂Boil glue, remove the negative electronic erosion-resisting

agent

5,6 on the nano-

electrode

7,8, the interval of finishing in top layer silicon 3 only is the preparation of the nano-

electrode

7,8 of 20-100nm.Figure 12 is the SEM surface picture of the heavy doping top layer silicon nano-electrode for preparing on the SOI substrate according to Fig. 6-specific embodiment flow process shown in Figure 10, and the spacing of electrode is 60nm among the figure.

Figure 11 and Figure 12 are respectively scanning electron microscopy (SEM) surface picture of the heavily doped silicon nano-electrode that is 60nm according to the SAL601 negative electronic erosion-resisting agent mask that Fig. 6-specific embodiment flow process shown in Figure 10 prepares and corresponding spacing on SOI (silicon-on-insulator) substrate.

Claims

1, a kind of employing negative electronic erosion-resisting agent utilizes electron beam lithography and etching technics to prepare the method for nano-electrode, it is characterized in that, comprises the steps:

(1) conductive layer of on substrate, growing;

(2) coating negative electronic erosion-resisting agent;

(5) develop;

(6) photographic fixing;

(8) remove photoresist.

2, the method for preparing nano-electrode according to claim 1 is characterized in that, wherein the substrate described in the step (1) is smooth, clean dielectric substrate: SiO ₂, or Si ₃N ₄, or Al ₂O ₃, or MgO or CaO, or be the Semiconductor substrate of high-impedance state: Si or Ge or GaAs or GaN or GaSb or GaP or AlAs or InAs or InP or InSb or SiC or ZnO or ZnS or CdS or CdTe or diamond.

3, the method for preparing nano-electrode according to claim 1, it is characterized in that, wherein the conductive layer described in the step (1) adopts metal material: Au or Ag or Pt or Al or W or Ti or Cr, transparent material: ITO, the semi-conducting material of good conductivity: Si highly doped, high conductivity or Ge or GaAs or AlAs or InAs or InP or SiC or ZnO or ZnS or CdS, these conductive layers are monocrystalline or polycrystalline attitude, are the single or multiple lift structures.

4, the method for preparing nano-electrode according to claim 1, it is characterized in that wherein evaporation or sputter or plasma reinforced chemical vapour deposition or low-pressure chemical vapor deposition or aumospheric pressure cvd or metal-organic chemical vapor deposition equipment or liquid phase epitaxy or molecular beam epitaxial method are adopted in the growth described in the step (1).

5, the method for preparing nano-electrode according to claim 1, it is characterized in that, wherein the negative electronic erosion-resisting agent described in the step (2) adopts SAL601 or HSQ or calixarenes, also needs to take between (4) step and (5) step baking step in back when adopting this chemistry of SAL601 to amplify resist.

6, the method for preparing nano-electrode according to claim 1 is characterized in that, wherein the e-beam direct-writing exposure described in the step (4) adopts JEOL JBX-5000LS electron-beam lithography system, and accelerating voltage is 50KeV, and electronic beam current is less than 100pA.

7, the method for preparing nano-electrode according to claim 1 is characterized in that, wherein the etching described in the step (7) adopts reactive ion etching or inductively coupled plasma etching or electron cyclotron resonace lithographic method.

8, the method for preparing nano-electrode according to claim 1 is characterized in that, wherein adopt special use to remove photoresist liquid removes photoresist or RIE dry method oxygen plasma removes photoresist or wet method the is removed photoresist method of removing photoresist described in the step (8).

9, the method for preparing nano-electrode according to claim 8 is characterized in that, it is dense H that wet method is removed photoresist with the #3 cleaning fluid ₂SO ₄+ H ₂O ₂Boil the glue method of removing photoresist.