CN1908813A - Method for preparation of X-lay photoetching mask plate - Google Patents

Abstract

The related preparation method for X-ray photoetching mark plate comprises: applying diamond film from heater CVD as the mark material, applying improved technology parameters and post-process to modify film performance; removing part silicon slice to form circular transparent opening and silicon support, and sticking a noble metal film on the diamond film.

Description

The preparation method of X-ray lithography mask

Technical field

The present invention relates to a kind of preparation method of X-ray lithography mask, belong to lay photoetching mask plate manufacturing technology field.

Background technology

Because therefore the exposure wavelength that optical lithography techniques is corresponding certain exists physics limit.And compare with other photoetching process, X-ray lithography technology has many advantages.Though the research of X-ray lithography starts from the seventies in 20th century,, never have practicability because it runs into such as difficulties such as mask material, light source and photoresists.In recent years, (maturation of 0.6～1.0nm) wavelength coverage light source technology, and the employing of proximity printing technology make acquisition become possibility less than the resolution of 0.1 μ m for strong, antidusting of collimation and the big synchrotron radiation X-ray of light intensity.Using also one of key key element of the X-ray lithography of synchrotron radiation is the mask that produces dependable performance on suitable substrate material.

The basic demand of X-ray lithography mask is as follows: (1) has through ability (greater than 50%) X ray, selects low atomic number material (being less than 10 μ m thickness) to reach enough to formula; (2) have high rigidity (high Young modulus) and low tension stress, to avoid any absorber plane and on-plane surface mechanical distortion; (3) for the mask in contact or the near field X-ray lithography technology, because it need support thick absorbent structure, its fracture strength is particular importance also; (4) profile pattern is good.Surfaceness should be fit to absorb the resolution of figure; (5) owing to the requirement of calibration process, optical transmittance should meet or exceed 50% at the 632.8nm place; (6) for absorber and silicon chip, the heat conductivity of mask and thermal expansivity should be consistent, to prevent any heat distortion; (7) good radiation hardness is to satisfy the stability in the time shutter, and promptly basal lamina material does not change its physical and mechanical property, prevents the change of absorber graph position on micro-crack or the mask.

People think that always the making of X ray mask will limit the practicability of X-ray lithography technology for many years, and this problem has not existed at present, and the manufacturing technology of X-ray lithography mask is ripe.The X-ray lithography mask of experimental study lining sill is mainly wanted Si, Si in the world in recent years _xN _y, SiC and be the macromolecular material etc. of representative with polyimide, alkyd resin etc.Absorber then often adopts Au, Ta, W etc.Recently studies show that in a large number that materials such as hydrogeneous SiN, BN and SiC can cause serious radiation damage after long-term heavy dose of synchrotron radiation rayed.This mainly is because after absorbing a large amount of X ray, the part hydrogen atom migrates to film surface, has produced the change and the chemical degradation of internal stress, causes geometric deformation and optical clarity to reduce.

Studies show that; adamas photomask blank material becomes one of the most attractive research topic; the diamond thin hydrogen content is few; only in the ppm magnitude; has good especially mechanics; calorifics and optical property; for example high Ji Shi modulus; high X ray and visible light transmissivity; high thermal conductivity and low-down thermal expansivity; and has a high radiation resistance; performance can not reduce yet under high dosage irradiation; basically meet the mask material requirement; making it become the best candidate of desirable synchrotron radiation photoetching photomask blank material of future generation, also is the hot topic of current this area research.Many in the world research groups have carried out the research work of the high resolving power adamas substrate mask that is compatible with commercial X-ray lithography machine, have obtained certain progress.The work of this aspect at present mainly concentrates on and optimizes the growing diamond membrane aspect, so that find every performance all to satisfy the film growth condition of making the high-resolution X-ray mask.From progress, further improving the surfaceness of diamond thin and improving optical transmittance is the key that realizes the X ray mask.Because adamantine surface energy is bigger, utilize the synthetic polycrystalline diamond films surface of general CVD technology comparatively coarse.Because adamantine surface energy is bigger, utilize the synthetic polycrystalline diamond films surface of general CVD technology comparatively coarse, be not suitable for traditional fine process.Therefore, generally to utilize the mode of mechanical buffing to realize the flattening surface of diamond thin.But diamond film surface hardness is very high, and polishing gets up to waste time and energy, yet nano-diamond film but has series of advantages such as smooth surface, friction factor are little.This patent proposes to adopt nanocrystalline diamond film to be applied to X-ray lithography photomask blank material.

The diamond thin that the present invention makes has surface of good flatness and very high optical transmittance.In the X-ray lithography technology, this photomask blank material can adapt to the nano level short wavelength of X ray, can obtain the photoetching resolution of 0.18 μ m.

Summary of the invention

The preparation method who the purpose of this invention is to provide a kind of X-ray lithography mask is characterized in that having following technological process and step:

A. the pre-service of tantalum wire: the heating source tantalum wire in traditional existing hot-wire chemical gas-phase deposition experimental provision is carried out the surface open up the mill purified treatment, and with hydrogen and acetone heating pretreatment 30 minutes, make tantalum wire surface removal oxide layer impurity, and at tantalum wire surface formation one deck tantalum carbide overlayer, with the volatilization of tantalum in the process of inhibition and the introducing of minimizing impurity;

B. the pre-service of silicon chip substrate: place HF solution 5 minutes earlier to remove the silicon surface oxidation layer; Then silicon chip substrate is used ultra-fine adamantine stone flour hand lapping 15 minutes; And then place the acetone soln ultra sonic bath to clean 15 minutes, and then place deionized water for ultrasonic to bathe again and cleaned 10 minutes, the surface is cleaned fully; Form the silicon chip minute surface simultaneously, increase the nucleation density of silicon chip surface;

C. the deposition of nano-diamond film: above-mentioned treated silicon chip substrate is positioned on the sample bench in traditional, the existing hot-wire chemical gas-phase deposition experimental provision, its minute surface upwards, carry out the deposition of diamond thin then, technological parameter in its operating process is: the throughput ratio of (1) hydrogen and acetone, hydrogen: acetone=180: 50 (ml/min); (2) temperature in the settling chamber is 620～680 ℃; (3) air pressure in the settling chamber is 1～3KPa; (4) apply bias voltage;

D. after electroless copper deposition operation reached certain hour, the thickness that makes nano-diamond film was between 1～2 μ m;

The aftertreatment of the diamond thin that e. prepares: (1) annealing, under Ar atmosphere, annealed 60 minutes for 500 ℃; (2) H is used in surface corrosion ₂SO ₄And H ₂O ₂The forms of corrosion of lean solution is removed graphite composition wherein;

F. removing the part silicon chip substrate supports to form silicon: on the structure of silicon-diamond thin, use HF: HNO ₃=1: 1 acid solution is removed the part silicon chip substrate, leaves the optical transmission window that diameter is 1.0cm, and beneath formation silicon supports;

G. attach the X ray bulk absorption body that one deck has certain design configuration at last on diamond thin, this absorber is the heavy metal element gold, forms saturating X ray district; And diamond thin forms the projection area of X ray as covering basal lamina material; Finally make mask with mask exposure figure.

Description of drawings

Traditional, existing hot-wire chemical gas-phase deposition experimental provision synoptic diagram that Fig. 1 adopts for the present invention.

The meaning that each numeric character is represented among the figure is as follows:

1-reaction chamber, 2-H ₂Gas tank, 3-fill bubbling bottle, 4-calibration cell, 5-tantalum wire, 6-Si substrate, 7-sample bench, 8-thermopair, 9-vacuum pump, 10-reduction valve, 11-mass flowmeter, 12-mass flowmeter, 13-temperature controller, 14-barometer, 15-valve, 16-bell jar, 17-cooling water pipe, the 18-biasing device of acetone.

Fig. 2 is a mask structural representation of the present invention.

Embodiment

After now specific embodiments of the invention being described in.

Embodiment 1

Technological process and step in the present embodiment are as follows:

1, the pre-service of tantalum wire: the heating source tantalum wire in traditional existing hot-wire chemical gas-phase deposition experimental provision is carried out the surface open up the mill purified treatment, and with hydrogen and acetone heating pretreatment 30 minutes, make tantalum wire surface removal oxide layer impurity, and at tantalum wire surface formation one deck tantalum carbide overlayer, with the volatilization of tantalum in the process of inhibition and the introducing of minimizing impurity;

2, the pre-service of silicon chip substrate: place FH solution 5 minutes to remove the silicon surface oxidation layer earlier the P type silicon chip of 2 * 2cm; Then silicon chip substrate is used ultra-fine adamantine stone flour hand lapping 15 minutes; And then place the acetone soln ultra sonic bath to clean 15 minutes, and then place deionized water for ultrasonic to bathe again and cleaned 10 minutes, the surface is cleaned fully; Form the silicon chip minute surface simultaneously, increase the nucleation density of silicon chip surface;

3, the deposition of nano-diamond film: referring to Fig. 1, above-mentioned treated silicon chip substrate is positioned on the sample bench in traditional, the existing hot-wire chemical gas-phase deposition experimental provision, its minute surface upwards, carry out the deposition of diamond thin then, technological parameter in its operating process is: the throughput ratio of (1) hydrogen and acetone, hydrogen: acetone=180: 50 (ml/min); (2) temperature in the settling chamber is 650 ℃; (3) air pressure in the settling chamber is 2KPa; (4) apply a bias voltage;

4, after electroless copper deposition operation reached certain hour, the thickness that makes nano-diamond film was between 1.5 μ m;

The aftertreatment of the diamond thin that 5, prepares: (1) annealing, under Ar atmosphere, annealed 60 minutes for 500 ℃; (2) H is used in surface corrosion ₂SO ₄And H ₂O ₂The oxidation corrosion mode of lean solution is removed graphite composition wherein;

6, removing the part silicon chip substrate supports to form silicon: on the structure of silicon-diamond thin, use HF: HNO ₃=1: 1 acid solution is removed the part silicon chip substrate, leaves the optical transmission window that diameter is 1.0cm, and beneath formation silicon supports;

7, attach the X ray bulk absorption body that one deck has certain design configuration at last on diamond thin, this absorber is the heavy metal element gold, forms saturating X ray district; And diamond thin forms the projection area of X ray as covering basal lamina material; Finally make mask with mask exposure figure.(as shown in Figure 2)

Claims (1)

1. the preparation method of an X-ray lithography mask is characterized in that having following technological process and step:

A. the pre-service of tantalum wire: the heating source tantalum wire in traditional existing hot-wire chemical gas-phase deposition experimental provision is carried out the surface open up the mill purified treatment, and with hydrogen and acetone heating pretreatment 30 minutes, make tantalum wire surface removal oxide layer impurity, and at tantalum wire surface formation one deck tantalum carbide overlayer, with the volatilization of tantalum in the process of inhibition and the introducing of minimizing impurity;

B. the pre-service of silicon chip substrate: place FH solution 5 minutes earlier to remove the silicon surface oxidation layer; Then silicon chip substrate is used ultra-fine adamantine stone flour hand lapping 15 minutes; And then place the acetone soln ultra sonic bath to clean 15 minutes, and then place deionized water for ultrasonic to bathe again and cleaned 10 minutes, the surface is cleaned fully; Form the silicon chip minute surface simultaneously, increase the nucleation density of silicon chip surface;

C. the deposition of nano-diamond film: above-mentioned treated silicon chip substrate is positioned on the sample bench in traditional, the existing hot-wire chemical gas-phase deposition experimental provision, its minute surface upwards, carry out the deposition of diamond thin then, technological parameter in its operating process is: the throughput ratio of (1) hydrogen and acetone, hydrogen: acetone=180: 50 (ml/min); (2) temperature in the settling chamber is 620～680 ℃; (3) air pressure in the settling chamber is 1～3KPa; (4) apply bias voltage;

D. after electroless copper deposition operation reached certain hour, the thickness that makes nano-diamond film was between 1～2 μ m;

The aftertreatment of the diamond thin that e. prepares: (1) annealing, under Ar atmosphere, annealed 60 minutes for 500 ℃; (2) H is used in surface corrosion ₂SO ₄And H ₂O ₂The forms of corrosion of lean solution is removed graphite composition wherein;

F. removing the part silicon chip substrate supports to form silicon: on the structure of silicon-diamond thin, use HF: HNO ₃=1: 1 acid solution is removed the part silicon chip substrate, leaves the optical transmission window that diameter is 1.0cm, and beneath formation silicon supports;

G. attach the X ray bulk absorption body that one deck has certain design configuration at last on diamond thin, this absorber is the heavy metal element gold, forms saturating X ray district; And diamond thin forms the projection area of X ray as covering basal lamina material; Finally make mask with mask exposure figure.

Images