WO1995015006A1

WO1995015006A1 - Washing apparatus, semiconductor production apparatus and semiconductor production line

Info

Publication number: WO1995015006A1
Application number: PCT/JP1994/001977
Authority: WO
Inventors: Tadahiro Ohmi
Original assignee: Tadahiro Ohmi
Priority date: 1993-11-22
Filing date: 1994-11-22
Publication date: 1995-06-01
Also published as: JPH07142438A

Abstract

This invention is directed to provide a washing apparatus, semiconductor production apparatus and a production line in which throughput is improved by terminating the reverse sides of substrates with hydrogen to keep dust away and by removing dust in gas phase if it stays so as to deliver cleaner substrates to the final process of a semiconductor production line. The apparatus comprises means for removing oxide film from the back of a substrate by supplying a chemical solution and means for blowing a gas containing active hydrogen species to the substrate surface exposed by the above means, wherein dangling bonds on the back of the substrate are terminated by active hydrogen species. The apparatus further comprises gas-phase dust collector means including at least one tank, means for holding the substrate inside the tank, means for supplying a gas having a moisture content of not greater than 100 ppb to the surface of the substrate and means for generating a Bernoulli effect on the substrate surface.

Description

Description Cleaning equipment, semiconductor manufacturing equipment and semiconductor manufacturing line

The present invention relates to a cleaning apparatus, a semiconductor manufacturing apparatus, and a semiconductor manufacturing line used in the production of semiconductors. In particular, the present invention relates to terminating the front and back surfaces of silicon wafers with hydrogen atoms to supply silicon wafers free from contamination. The present invention relates to a possible cleaning device, a semiconductor manufacturing device, and a semiconductor manufacturing line. Background art

In the semiconductor manufacturing process, for example, debris adhering in the substrate processing tank and during the transportation of the substrate is the largest cause of a decrease in yield. Therefore, the cleaning process for removing impurities such as dust is one of the most important processes in the semiconductor production process.

For example, in the process of forming a plasma insulating film, if dust adheres to the surface of silicon wafers, the film is deposited on the dust and local unevenness in film formation occurs. However, the gate insulating film of a MOS transistor formed on silicon is destroyed, and the leakage current at the junction of the transistor increases, and in the case of alkaline ions, the performance of the transistor such as a change in the threshold value of the transistor is adversely affected. Exert.

In the process of forming a metal film by sputtering, debris adhering to the substrate surface is taken into the metal film and deteriorates the flat film forming property of the metal wiring. Also, if metal film formation is performed while dust is present in the contact hole and through hole, after the wiring is formed, the resistance of the contact hole and through hole increases, and the migration resistance of the contact hole and through hole wiring increases. This causes a problem of deterioration.

Alternatively, in dry etching of aluminum metal wiring, if dust made of a material that is difficult to etch adheres to the aluminum surface during etching, the lower portion of the dust is not etched, and the periphery of the dust is etched, resulting in an etching residue (etching residue). Usually, additional etching (so-called over-etching) is performed. Although the etching residue is removed, excessive overetching results in a reduction in the thickness of the resist mask and the underlying oxide film. Also, due to neutral radical species during overetching, the etching of the aluminum wiring in the horizontal direction progresses, and the wiring becomes thin. Furthermore, in the aluminum wiring area over the step, additional etching to remove the etching residue, so-called over-etching, is less than that in the aluminum part of the flat part.Therefore, the etching residue is spread between the metal wirings when dust adheres to the step. This causes a problem of short-circuiting of the metal wiring.

In order to remove such dust, conventionally, a jet method in which a chemical solution is supplied to the substrate surface from the upper surface of the substrate by using a nozzle or a shower and washed, or a dry method in which the chemical solution is removed by ion irradiation, gas injection, or the like has been adopted. However, depending on the material of the substrate surface, etching may occur and the wet method may not be adopted, and the current dry method may cause problems such as generation of lattice defects due to ion bombardment and insufficient removal capability. is there.

Further, there is a problem that even if dust on the surface of the substrate is removed, the production yield is not necessarily improved. This is a problem caused by dust on the back surface of the base. Since the back surface of the substrate often comes into contact with metals, resins, ceramics, and other materials in the transport system and processing tanks, it is easily contaminated by these materials, and no matter how clean the surface is, Garbage attached to the back surface of the substrate and the surface of the substrate are contaminated, so-called cross-contamination (cross contamination) occurs. These phenomena were actually found for the first time by the present inventors in examining higher performance and higher integration of semiconductor devices.Dust on the back surface affects the characteristics of semiconductor devices and the manufacturing yield. It has been found that this is a big problem.

Furthermore, if dust adheres to the back surface of the base, a minute gap is formed between the base and the support in the semiconductor manufacturing apparatus and the semiconductor manufacturing line, and the heat conductivity between the base and the support is deteriorated by the gap. However, the efficiency of heating or cooling from the support to the substrate deteriorates. If the back surface of the substrate is contaminated, problems may occur such as the substrate dropping during transport or the inability to detect the position of the substrate. Erroneous detection of the substrate position is caused by erroneous detection due to a minute gap between the detector of the substrate and the back surface of the substrate, or because the substrate is in an electrically floating state, and the substrate is charged with static electricity and the substrate position detector malfunctions. . Further In addition, in the process of transferring the pattern on the reticle to the resist, if the stepper has a shallow focal depth, if the back surface of the substrate is contaminated, the gap between the substrate and the support will cause the depth of focus of the stepper to decrease. There is a problem that the resolution is degraded and the resolution of resist patterning is deteriorated.

The present invention makes it possible to suppress the adhesion of dust that causes a decrease in yield by terminating the back and front surfaces of the substrate with hydrogen, and also to enable the removal of the dust easily in the gas phase, thereby providing a cleaner substrate. To provide a low-cost cleaning apparatus, a semiconductor manufacturing apparatus, and a semiconductor manufacturing line capable of surely sending waste to the final process of a semiconductor production line and completely eliminating the influence of dust in each process. I do. Disclosure of the invention

The cleaning apparatus of the present invention is a cleaning apparatus for cleaning and drying the back surface of a substrate, comprising: a means for supplying a chemical solution to the back surface of the substrate to remove an oxide film generated; and a hydrogen active species on the substrate surface exposed by the means. And a means for spraying a gas containing: a dangling bond on the back surface of the substrate is terminated with hydrogen by the hydrogen active species. The cleaning apparatus preferably includes at least means for supplying a chemical solution to the surface of the substrate to clean the surface, and means for blowing a gas containing a hydrogen active species onto the surface. The semiconductor manufacturing apparatus according to the present invention is a semiconductor manufacturing apparatus having a substrate transport means, wherein a treatment tank connected to the transport means and exposing a back surface of the substrate and terminating dangling bonds with hydrogen is provided. And The processing tank that exposes the back surface of the base and terminates the danglide with hydrogen is preferably the above-described cleaning apparatus of the present invention. The semiconductor manufacturing line of the present invention has a plurality of semiconductor processing tanks. In a semiconductor manufacturing line provided with transport means between semiconductor processing tanks, at least one processing tank for exposing the back surface of the base and terminating dangling bonds with hydrogen is provided. Further, it is preferable that the treatment tank exposing the back surface of the base and terminating the dangling bond with hydrogen is the cleaning apparatus of the present invention.

Further, the semiconductor manufacturing line of the present invention comprises: at least one processing tank; means for holding a substrate in the processing tank; and a water concentration of 10 Op Db or less on the surface of the substrate. It is preferable to provide a gas-phase dust removing device comprising a means for supplying gas and a means for generating a Bernoulli pressure difference on the surface of the base. Action

Hereinafter, the operation of the present invention will be described together with embodiments.

A cleaning solution (chemical solution, ultrapure water, etc.) is supplied to the back of the base to remove the oxide film formed on the back, and then a gas containing active hydrogen species is sprayed on the back of the base while the back of the base is being dried. Thereby, the back surface of the base can be simply and completely terminated with hydrogen. Hydrogen active species are very active and have been considered to have a short life in the past.However, by adopting the structure of the present invention, hydrogen active species are generated by catalytic reaction immediately before introduction into the cleaning tank of the cleaning device. The use of a high-purity inert gas and hydrogen gas, and the means for supplying the gas containing hydrogen active species is made of a material having a catalytic action, thereby substantially extending the service life. As a result of supplying hydrogen active species at a concentration to the surface of the substrate, hydrogen termination on the rear surface of the substrate can be completely performed as described above.

Similarly, the substrate surface can be terminated with hydrogen by washing the substrate surface with various chemicals and ultrapure water or the like, and then spraying a gas containing a hydrogen active species onto the substrate surface during drying.

Although the details of the reason why the adhesion of dust can be suppressed by terminating the substrate with hydrogen are not clear at present, it has been conventionally known that a large amount of water is adsorbed on the front and back surfaces of the substrate. The dust easily adheres to the surface of the substrate, and if the dust adheres to the substrate, a liquid bridging force is generated between the dust and the substrate due to the surface tension of moisture, and the liquid bridging force is lower than the van der Waals force. Since it was about 10 times larger, the attached dust could not easily be separated from the substrate, but due to the hydrogen termination of the present invention, moisture was hardly adsorbed on the front and back surfaces of the substrate, and as a result, the dust was removed. It is considered that adhesion is suppressed.

Next, as an example of the cleaning device of the present invention, a cleaning device capable of cleaning and drying the front and back surfaces of the substrate will be described with reference to FIG.

FIG. 1 shows the cleaning apparatus used in this embodiment. In FIG. 1, 101 is a cleaning tank, 102 is a plurality of chemical liquid nozzles connected to various chemical liquid supply devices (not shown), 103 is a substrate, 104 is a rotary chuck (substrate holding member), 105 is an exhaust / drain port, 106 and 107 are gases containing active hydrogen species on the front and back surfaces of the substrate, respectively. A means for supplying gas (gas supply pipe), 108 is a nozzle for supplying a chemical solution and ultrapure water for removing the oxide film on the back surface of the wafer while moving, 109 is a rotary motor, 110 is a rotary motor Means for generating a hydrogen active species provided with a heating means 111; a valve 112 for controlling the supply of a gas containing a hydrogen active species, whereby the gas is supplied to the front surface or the back surface of the substrate or both. 1 13 is a mixer of N ₂ gas and H gas, 1 14 is a mixed gas pipe, 1 15 and 1 16 are N ₂ gas pipe and H ₂ gas pipe, respectively. It is connected to an N ₂ gas supply device and H ₂ gas supply device (not shown) via a flow controller.

The cleaning tank can be one that introduces various chemicals or ultrapure water into the inside and cleans the base by immersing the base. The base is mounted on a rotary chuck and the base is rotated while the chemical or ultrapure water is applied. The method shown in FIG. 1 in which washing is performed by spraying water is preferable. After cleaning with a chemical or ultrapure water, a gas containing a hydrogen active species is finally blown onto the substrate and dried, so that dangling bonds generated by the cleaning can be effectively terminated with hydrogen. Needless to say, the members constituting the cleaning tank are made of a material having resistance to various chemicals used for cleaning. The drying of the substrate is preferably performed while rotating the substrate.

As the means 10 for generating the hydrogen active species, for example, a material in which a part or the whole of the inner surface of a pipe is made of a material serving as a catalyst for a hydrogen radicalization reaction can be used. By flowing a mixed gas of an inert gas and a hydrogen gas through such a pipe, the hydrogen gas in the mixed gas can be converted into active species such as radicals. In order to increase the activation efficiency, it is preferable to heat the catalyst (pipe). The heating temperature is preferably from 300 to 450 ° C, more preferably from 300 to 400 ° C. When the temperature is lower than 300 ° C, the amount of active hydrogen species generated is small.When the temperature exceeds 450 ° C, the amount of active hydrogen species increases, but a passive film is formed on the inner surface of the pipe. Otherwise, impurities may be released from the surface and mixed into the mixed gas. In the present invention, as the catalyst used for generating the hydrogen active species, a material containing Ni is preferable, and for example, a Ni-based alloy is preferable. Also, among Ni-based alloys, Mo-based alloys and Ni-W-based alloys are preferred. More specifically, for example, Hastelloy (registered trademark) can be mentioned.

As an example of the above piping, for example, stainless steel which is electrolytically polished to a surface roughness of 1 m or less is used. In this case, it is more preferable that a passivation film formed by heat treatment in an oxidizing atmosphere having an impurity concentration of 1 Op pb or less is formed on the surface of the stainless steel. Further, a passivation film formed by performing a reduction treatment in a hydrogen atmosphere after the formation of the passivation film is more preferable. Since the surface of such a passivation film contains chromium oxide as a main component, the incorporation of impurities into the mixed gas can be suppressed. The passivation film is mainly composed of chromium oxide, but contains nickel oxide, and the nickel oxide acts as a catalyst and contacts the surface of the passivation film. It is considered that the activated hydrogen gas is activated to generate active hydrogen species. In the present invention, it is needless to say that the means 10 for generating hydrogen active species may be, for example, a fiber-like, mesh-like, sponge-like, or tubular catalyst provided in a vessel in addition to the above-mentioned pipe-like one. In addition, such a shape is advantageous in that the contact area with the hydrogen gas is increased and the activation efficiency is increased.

The impurities in the inert gas and the hydrogen gas used in the present invention are preferably at most 10 ppb, more preferably at most 1 PPb. The mixing ratio of the hydrogen gas in the mixed gas is preferably 0.1% or more, more preferably 10% or more. Within this range, the generation amount of hydrogen active species is further improved. He gas and N are used as the inert gas. Gas, Ar gas and the like are preferably used. In particular, N ₂ gas and Ar gas are preferable. The means 6 and 7 for supplying a gas containing a hydrogen active species according to the present invention are used to guide an active gas containing a hydrogen active species generated by a means for generating a hydrogen active species to a cleaning tank. Generally used. As described above, in order not to lower the concentration of the generated hydrogen active species, it is preferable that the inner surface be made of a material containing, for example, Ni.

The means for supplying the gas containing hydrogen active species preferably has at least one or more independent nozzles directly above the surface of the substrate and directly below the rear surface of the substrate. It has a large number of independent nozzles, and by irradiating gas from multiple directions, it is possible to terminate hydrogen on the front and back surfaces of the substrate. The means for supplying the gas to the back surface of the substrate is such that a chemical solution or the like is sprayed during the back surface cleaning. It is preferable to use a movable structure that can retreat or a structure that can cover the nozzle so that it does not enter the inside of the nozzle.

Next, an example of a cleaning process using a silicon wafer will be described. Other chemicals, gases, and objects to be cleaned may be performed in the same manner.

In the cleaning process, the silicon wafer to be cleaned is rotated, for example, ozone-added ultrapure water (ozone: 2 to 10 ppm) → ultrapure water rinse → hydrofluoric acid + hydrogen peroxide + ultrapure water (eg, volume Ratio: 0.03: 1: 2) → ultrapure water rinse-ammonium hydroxide + hydrogen peroxide + ultrapure water (for example, volume ratio of 0.05: 1: 5) → ultrapure water rinse → fluor hydrogen acid tens ultrapure water → ultrapure water rinsing → spin drying (e.g. N ₂ H ₂ gas concentration in the gas: 1 0 to 1 0 0%) carried out in such process. Here, during each cleaning step, a nitrogen gas to which a hydrogen active species has been added is introduced into the cleaning chamber.

In order to remove the natural oxide film formed on the silicon wafer before the cleaning process and the natural oxide film generated during the cleaning process, the natural oxide film must be removed with hydrofluoric acid at least immediately before the drying process. U, want to do.

In addition, the chamber for performing these cleanings is preferably a sealed one, and is preferably sealed at least with some inert gas. Addition of active hydrogen species Since all processes are performed in a single sealed cleaning tank that can introduce nitrogen gas, a natural oxide film can be formed on the silicon surface exposed by hydrofluoric acid. In addition, it is possible to completely terminate the silicon wafer surface with hydrogen active species during the drying process.

Further, it is more preferable that the concentration of the hydrogen active species can be adjusted by providing a mass flow controller at the introduction portion of each gas to the hydrogen active species generator. By controlling the concentration, it becomes possible to supply the necessary amount of active hydrogen species when necessary and to terminate the hydrogen.

Next, referring to FIG. 2, a gas-phase dust removing apparatus for removing dust adhering to the substrate surface in a vapor phase in a processing tank such as a film forming tank or an etching tank and a transfer system will be described.

In the figure, reference numeral 201 denotes a vacuum processing tank. For example, the degree of vacuum in the vacuum processing tank 201 is 10—10 by a turbo molecular pump 202 and a roughing pump 203.

12, "

'Torr can be kept. 205 is an evacuation passage via an on-off valve 204 It is connected to the vacuum processing tank 201.

The vacuum processing chamber 2 0 1, for example made of a vacuum molten SUS 3 1 6 L, its inner surface 2 0 6 mirror polished, and C r ₂ 0 ₃ film is passivated is formed, released The surface has very little adsorption of gas and moisture.

Reference numeral 207 denotes a base, for example, silicon wafer. Of course, the present invention is not limited to silicon wafers, but may be another semiconductor substrate (for example, a compound semiconductor substrate), a magnetic substrate, or a superconductor substrate. Reference numeral 208 denotes a support (holding means for holding the substrate) for holding the substrate 207, and has, for example, a substrate holding mechanism using a vacuum or electrostatic attraction method.

Reference numeral 209 denotes dust adhering to the substrate 207, and reference numeral 210 denotes a flow of, for example, N ₂ gas blown from the gas outlet 211 onto the substrate 207. You.

Reference numeral 211 denotes an N ₀ gas outlet provided on the substrate, which is connected to the gas supply passage 2 1 2, and a high-speed N ₂ gas is supplied onto the substrate 1 07 by the gas supply control valve 2 1 3. It is for flowing constantly. Here, 214 is a high-pressure gas supply source, for example, a high-pressure N _n cylinder. The high-pressure N ₂ cylinder 2 14 is connected to the steady-state flow path 2 16 and the high-pressure gas control unit 2 17 through the high-pressure gas supply path 2 15. The steady flow passage 2 16 is provided with, for example, an electric heating mechanism or another heating mechanism 2 18 so that the N ₂ gas can be heated to about 80 ° C. 217 has a mechanism to control the intermittent and agile flow of high-pressure gas.

In Fig. 2, the intermittent high-speed opening and closing of the high-speed on-off valve 29.2.20 causes intermittent and rapid pressure fluctuation from the high-pressure section 2 21 through the gas supply passage 2 12 and the gas outlet 2 1 1. Can affect the steady gas flow over the substrate surface. The frequency of pressure fluctuations is, for example, 10 times Z times.However, drive the high-speed on-off valves 219, 220 at a higher speed, or install multiple high-pressure gas control units 217 in parallel. As a result, the frequency of intermittent pressure fluctuations can be further increased.

N. Since the moisture concentration of the gas is controlled at 100 to 100 ppb, the moisture concentration in the vacuum processing tank 201 can be kept at least at 10 ppm or less, and the absorbed moisture amount at this time is approximately Each is 1 × 10 ¹⁵ molecules cm ² . This translates into a bilayer on average. Hit.

Reference numeral 22 denotes an exhaust passage for N ₂ gas and dust, which is connected to the vacuum processing tank 201 via an on-off valve 22 3, and dust separated from the substrate is subjected to the flow of N ₂ gas. In this way, the gas is discharged to an exhaust gas treatment device such as a scrubber outside the system via the on-off valve 224. The exhaust passage 222 is connected to a roughing pump 203 via an on-off valve 222 and a rough exhaust passage 222 to keep the inside of the vacuum processing tank at a reduced pressure (for example, 1 OOT orr). while N ₉ can it to discharge the gas and dust associated with it.

Reference numeral 227 denotes, for example, an Xe lamp for raising the temperature of the substrate 207. Reference numeral 2 28 denotes a light inlet connected to the vacuum processing tank 201, for example, provided with a window material 229 made of optically polished synthetic quartz or the like, so that light from the Xe lamp 227 is provided. The surface of the substrate 207 can be uniformly irradiated. Further, by controlling the output of the Xe lamp 227, the temperature of the base body 207 can be raised and maintained at a constant temperature (for example, 100 ° C.).

Reference numeral 230 denotes a transfer chamber provided with a mechanism for freely transferring a substrate between the vacuum processing tank 201 and another processing tank (not shown). The substrate transfer chamber 230 is connected to a vacuum processing tank 201 via an on-off valve 231. The moisture concentration in the substrate transfer chamber 230 is controlled to 10 ppm or less, as in the vacuum processing tank 201.

The present inventor has found that when dust is adsorbed on the substrate surface in the gas phase, the forces acting between the dust and the substrate are a liquid crosslinking force and a Van der Waals force. In particular, when water is present on the substrate surface, the liquid crosslinking force is dominant.

In the present invention, the liquid cross-linking force between the dust adhering to the substrate surface and the substrate is eliminated, and the dust is deposited on the substrate only by van der Waalska, which is at most as small as the square of the distance between the lattices of the substrate. A state where it adheres is realized. The inventor has found that this is achieved when the amount of adsorbed moisture on the surface of the substrate is substantially less than 2 molecular layers. It is not clear how these bilayers are present, but the definition of two or less molecular layers means not only when the entire substrate surface is two or less molecular layers, but also when there is no water molecular force. It can be said that this also includes the case in the department.

In order to realize such a state, the moisture concentration of the gas supplied to the substrate surface Must be less than 100 ppb. It is preferable to minimize the release of moisture from the members constituting the treatment layer or the surface of the gas supply system piping, etc., so that such members are made of a passivation film mainly composed of chromium oxide. Use the one formed on the surface of the contact part of

In the present invention, a means for generating a Bernoulli pressure difference on the surface of the base is provided. As described above, the present inventor has found that when the influence of the liquid crosslinking force is eliminated, dust can float and be removed from the substrate surface if a Bernoulli pressure difference is applied to the substrate surface. For example, when N ₂ gas is blown at a flow rate of 2501 / min from the gas outlet (eg, N ₉ gas) 2 11 in FIG. 2, the average flow rate of N ₂ gas at the substrate surface Is about 3 O m / sec. This N. It is thought that a stagnant layer occurs in the region of several m / s to several 10 m from the surface of the substrate due to the high-speed flow of . For example, the pressure difference occurring at the interface of the high-speed flow and stop flow layer of the flow rate of about 3 O m / sec was found to be approximately 0. 5 k gZ cm ² approximately. This pressure difference gives relatively large debris, for example of the order of 5 and 1 m, a kinetic energy perpendicular to the substrate. Based on mechanical considerations, this vertical kinetic energy can be sufficient to separate dust of 1 zm or more from the substrate surface. The gas flow rate may be appropriately determined according to the particle size of the dust, but is preferably 1 O mZ sec or more, and more preferably 3 O mZ sec or more. In the case of such a high-speed flow, the removal efficiency is improved. Note that the upper limit is preferably 5 O mZ sec.

Incidentally, for example, 0.3 relatively small dust of about zm is completely order to present inside Tomaryu layer, with only the pressure difference caused by the high-speed flow of N ₂ garbage may not be detached from the substrate surface. It is effective to apply intermittent pressure fluctuations (for example, shock waves) to the substrate surface or to a high-speed gas flow flowing over the substrate surface in order to remove this 0.3 μm dust from the substrate surface. Was clarified from the experimental facts of the inventor. This intermittent pressure fluctuation (for example, shock wave) is considered to have the effect of disturbing the stagnant layer that is generated from several zm to several 10 m from the substrate surface. This is a moment turbulence retention layer is caused by the intermittent pressure fluctuations (e.g. shock waves), Available from Atsuta substrate surface in the stop flow layer with high velocity flow only N ₂ into the following areas several im L, even According to Bernoulli's theorem Pressure difference can be generated. Due to this pressure difference, dust on the surface of the substrate gives kinetic energy in a direction perpendicular to the surface of the substrate.

It is thought that it can fly up about 〃m. The sowed dust is instantly carried out of the vacuum chamber by a high-speed flow of N ₉ flowing on the surface of the substrate. Since the high-speed flow of N _{2 is} a high-speed flow (for example, 1 O mZ sec or more as described above), there is no opportunity for dust present in the N ₂ that has detached from the substrate surface to reattach to the substrate.

According to the present invention, dust can be removed from the surface of the substrate by the above operation. Increasing the temperature of the substrate or dust adhering to the substrate using, for example, a Xe lamp (for example, a gas (for example, N ₂ gas) heated to TC) such as 8 (TC) also removes moisture adsorbed on the substrate surface. This further promotes the effect of reducing the liquid crosslinking force.

On the surface of the substrate, where the force acting on the substrate and the dust is expressed only by van der Waals forces, the attached dust always moves freely on the substrate surface by Brownian motion. The energy of the Brownian motion is determined by the temperature. For example, if the temperature of the dust is increased, the dust moves on the substrate surface by the kinetic energy proportional to the temperature. For example, raising the temperature with a Xe lamp or the like can activate the dust browning motion. Dust moving around the surface of the substrate jumps up due to irregularities of several angstrom on the surface of the substrate, and at this moment, the van der Lusker working between the substrate and the dust is minimized, and the dust is most detached from the substrate. It is easy to do.

Also, Brownian motion is an irregular motion of dust, so there is also motion in the direction perpendicular to the substrate. Therefore, even in this operation, van der Waalska working between the substrate and the dust can be minimized.

Great care must be taken when raising the temperature of garbage. The inventor of the present invention has found that a dust removal effect appears at a substrate temperature of 80 ° C or higher.However, as described above, it is more effective to activate the browning motion if the temperature is as high as possible. For obvious reasons. However, in the actual process, it is very difficult to determine the type of dust adhering to the substrate surface, and naturally includes organic substances and the like. Therefore, heating at a temperature lower than the temperature at which organic substances are dissolved (for example, 200 ° C or lower) is ideal. You. Furthermore, considering that the entire process is performed at a low temperature (around 400 ° C), heating above 300 ° C may have an effect on the heat treatment even if no organic matter is observed. Not preferred. For the above reasons, the heating of the substrate and the dust is preferably carried out at a temperature of from 80 ° C. to 300 ° C., more preferably from 80 ° C. to 200 ° C.

Until now, reference has been made for the removal of dust by inert N ₂ gas, a reactive gas, for example, C 1 ₂ gas or which the gas obtained by mixing an inert gas such as A r on the substrate surface constantly flowing, metallic dust on the substrate, for example if a a 1, a 1 C 1 ₃ is formed by the reaction of C 1 ₂ gas and a 1, considering that this is a volatile Then, it can be easily removed by synergy with intermittent and agile pressure fluctuation.

In addition, for example, a reactive gas such as o ₃ can be applied to organic dust, and for example, HF gas can be considered to SiO ₂ dust.

These are merely examples, but by selecting a reactive gas and providing a gas system switching mechanism, more effective debris removal utilizing the chemical reaction as well as the gas phase debris removal effect of the present invention can be achieved. It is possible.

Also, by introducing the ionized gas into the vacuum chamber, it neutralizes the static electricity of the substrate, cancels the electrostatic force acting between the dust in the gas phase and the substrate, and attaches or removes the dust in the gas phase to the substrate. Prevents redeposition. For ionizing the gas, for example, a deuterium lamp or a soft X-ray light source can be used.

Further, it is possible to efficiently remove dust on the surface of the base by giving a mechanical vibration such as an ultrasonic wave.

Also, when intermittent and agile pressure fluctuation is applied while supplying liquefied N ₂ to the substrate, dust can be more efficiently removed from the substrate. This is because a liquid that easily vaporizes at room temperature, such as liquefied N ₂ , vaporizes with a kind of explosion-like action. At this time, a shock wave having a wavelength of about several m is involved, and it is considered that this shock wave gives kinetic energy to dust adhering to the substrate. It is considered that the kinetic energy causes the dust to be very easily separated, and that the dust is completely separated from the substrate by intermittent and agile pressure fluctuations. Thus, the substrate table It is considered that the debris that has separated from the surface is transported to the outside by the steady gas flow created by the vaporized liquid. As such a liquid that easily vaporizes at room temperature, a liquid such as liquid Ar or isopropyl alcohol is suitably used in addition to liquefied N ₂ . BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a conceptual diagram showing an example of the cleaning device of the present invention.

FIG. 2 is a conceptual diagram showing an example of a gas-phase dust removing device.

FIG. 3 is a conceptual diagram illustrating a semiconductor manufacturing apparatus according to the second embodiment. FIG. 4 is a conceptual diagram showing another example of the semiconductor manufacturing apparatus.

FIG. 5 is a conceptual diagram showing another example of the semiconductor manufacturing apparatus.

FIG. 6 is a conceptual diagram illustrating a semiconductor manufacturing line according to the third embodiment.

(Explanation of code)

1 0 1 Cleaning tank,

1 0 2 Chemical nozzle,

103 substrate (S i ゥヱ c),

1 0 4 Wafer chuck,

1 0 5 Exhaust outlet

106, 107 means for supplying gas containing hydrogen active species (gas supply pipe),

1 0 8 Backside cleaning nozzle,

1 0 9 Rotary motor,

Means for generating 110 active hydrogen species,

1 1 1 heating means,

1 1 2 Switching valve,

1 1 3 Mixer of N ₂ gas and H gas

1 1 4 Mixed gas piping,

1 1 5 N ₂ gas piping,

1 16 H ₉ gas piping.

2 0 1 Vacuum processing tank, 202 molecular pump,

203 roughing pump,

204 on-off valve,

205 vacuum exhaust passage,

207 silicon wafer (base),

208 support (means for holding the substrate),

209 trash,

2 10 N ₂ gas flow,

2 1 1 N 9 gas outlet,

21 2 Gas supply passage,

2 1 3 Gas supply control valve,

2 1 4 High pressure gas supply,

21 5 High-pressure gas supply passage,

2 1 6 Steady flow passage,

21 7 High-pressure gas control unit,

2 18 heating mechanism,

2 1 9, 220 High-speed on-off valve,

22 1 High pressure section,

222 exhaust passage,

223, 224, 225 on-off valve,

226 rough exhaust passage,

227 X e lamp,

228 light inlet,

229 window materials,

230 transfer room

23 1 On-off valve. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in more detail with reference to Examples. It is not limited to.

(Example 1)

Using the semiconductor manufacturing apparatus in which the cleaning apparatus shown in FIG. 1 was connected to the plasma oxidation processing apparatus via the transfer chamber, the silicon wafer was subjected to hydrogen termination on the front and back surfaces, and then an oxide film was formed.

In this example, as a means 10 for generating hydrogen active species, a 10 m diameter Ni wire was rolled and bundled and inserted into a cylindrical stainless steel (SUS 316) container whose inner surface was electropolished. The mixture was heated to 350 ° C over 13 days. In addition, stainless steel tubes (SUS 316) whose inner surfaces were electropolished were used for the gas supply tubes 6 and 7. The mixing ratio of the mixed gas, N ₂ 90%, and the H ₂ 10%.

First, a cleaning method using a cleaning device will be described.

N ₂ gas containing a hydrogen active species is introduced from nozzle 6, and while rotating the nozzle at 150 to 3000 rpm, 1 ) Caro ultrapure water with ozone (2-1 Oppm), 2) Hydrofluoric acid + hydrogen peroxide + ultrapure water (0.03: 1: 2), 3) ammonium hydroxide + hydrogen peroxide + Ultrapure water (0.05: 1: 5), hydrofluoric acid + hydrogen peroxide + ultrapure water (0.03: 1: 2)), and ultrapure water were sequentially dropped and washed. Subsequently, while blowing a gas containing a hydrogen active species from the mixed gas supply pipes 6 and 7 onto the front and back of the wafer, the wafer was rotated at 1500 rpm and dried.

The wafer cleaned as described above was transferred to a plasma oxidation apparatus by a transfer means in a transfer chamber, and a 1-Om oxide film was formed. For comparison, a non-backside treated nanowas similarly transported to a plasma oxidation apparatus to form an oxide film.

When the dielectric strength of the above oxide film was measured, it was found that, compared to the case where the back surface treatment was not performed, the dielectric strength of the present example could stably obtain a high dielectric strength. (Example 2)

FIG. 3 shows a semiconductor device characterized in that at least a part thereof includes means for automatically transporting a silicon wafer in which the substrate surface on the back surface of the silicon wafer is exposed and the exposed silicon surface is terminated by hydrogen atoms. 1 shows an embodiment of a production line. In FIG. 3, reference numeral 301 denotes a cleaning device of the present invention, and 302 and 303 denote cleaning devices. This is a vacuum chamber for storing husets. 304 is a transfer mechanism having means for transferring the silicon wafer to each processing tank. Numeral 305 denotes a vacuum tank for transferring silicon wafers to each processing tank. 306, 307, 308, 309, 310 are used for dry etching, plasma film formation, thermal decomposition film formation, sputter film formation, etc. for processing silicon wafers, for example. It is a vacuum chamber.

As described above, dust adheres to the back surface of the wafer during transfer. If this wafer is transported to the next processing tank with the dust attached to it and processed, for example, if it is sent to a dry etching processing tank, a gap is created between the wafer and the support, and Heat conduction efficiency deteriorates. As a result, the temperature of the wafer rises due to the heat supplied from the plasma. For example, in the etching of aluminum metal wiring containing silicon, there is a problem that the aluminum wiring is isotropically etched due to the temperature rise of the wafer.

In this embodiment, in order to solve this problem, before transporting the wafer to the dry etching treatment tank, the cleaning device 301 terminates the back surface of the wafer with hydrogen atoms, and the back surface of the wafer hardly adsorbs moisture. This also contributes to preventing dust from adhering. As described above, according to the present invention, anisotropic dry etching can be realized as a result of preventing dust on the back surface.

In addition, if dust adheres to the back surface, the dust may rise in the dry etching tank and adhere to the wafer surface. In this case, the dust becomes a fine mask and may cause an etching residue, which causes a low yield in manufacturing large-scale integrated circuits of silicon. However, in this example, no etching residue was observed, and this problem could also be solved. One

In the present embodiment, the tanks are stored between the tanks for storing the oxygen cassettes 302 and 303 and the vacuum tanks for transporting the silicon wafers to the processing tanks 300, respectively. It is important to connect the cleaning device to the cluster-type semiconductor manufacturing device, terminate the silicon wafer and the back surface with hydrogen, and prevent dust from adhering to the wafer and the back surface.For example, as shown in FIGS. One or more of the cleaning apparatuses of the present invention may be installed at other positions, and the cleaning apparatus of the present invention may be at least partially integrated with a cluster-type semiconductor manufacturing apparatus and at least partially integrated. The present apparatus may be incorporated anywhere in a line of single-wafer type semiconductor manufacturing apparatuses.

(Example 3)

In this embodiment, at least a part of a cleaning apparatus and a dust removing apparatus of the present invention, or a semiconductor processing apparatus of a single-wafer processing type or a cluster type incorporating these apparatuses is provided. This embodiment will be described with reference to this embodiment.

In FIG. 6, reference numeral 601 denotes a nitrogen atmosphere tunnel for automatically transporting a silicon wafer to each semiconductor manufacturing apparatus for each wafer (hereinafter referred to as a nitrogen tunnel). 602 is a silicon wafer to be transported. For example, 603 is a reactive ion etching device, and 604 is a plasma film forming device. Reference numeral 605 denotes a cluster-type semiconductor manufacturing apparatus having a plurality of processing tanks and means for transferring silicon wafers to the processing tanks. 606 is a stepper, for example, and 607 is an ion implantation device. 608 is the cleaning device shown in FIG. Further, 609, 610, 61 1, and 612 are the dust removing devices shown in FIG. Numeral 613 is a vacuum tank having means for transferring silicon wafers to each processing tank. Reference numerals 615, 616, and 617 denote vacuum chambers such as a dry etching tank, a thermal decomposition film forming tank, and a sputter film forming tank for processing a silicon wafer. Each tank and nitrogen tunnel are made of, for example, vacuum-melted S US 316, the inner surface of which is mirror polished and made of Cr. 0 ₃ film in the released gas and moisture are passivated adsorption that has become extremely small surface. The water concentration of the high-pressure gas used in this treatment tank is 10 to 100 ppb. Thus, it goes without saying that the water concentration in each of the vacuum chambers and the nitrogen tunnel is kept at most 10 ppm or less.

The great effect of this embodiment is that, for example, the silicon wafer is isolated from atmospheric components and manufacturing workers by a nitrogen tunnel, and the dust attached in the treatment tank is removed by the dust removing device of the present invention. Dust that is dusting (for example, dust that adheres to workers wearing dust-proof clothing in a clean room and adheres to the air during the work due to the blowing of air from the cuffs and collars of the dust-proof clothing) and reactions The dust attached to the wafer in the processing tank is removed by the dust removing device of the present invention, and the wafer is transferred to the next processing tank. For the first time, a large clean room space is no longer required. In addition, in each of the semiconductor manufacturing processes, for example, in the case of heavy metal for contamination (for example, in the case of dry etching, the metal formed by the reaction processing tank sputters the metal wall of the processing tank in the case of heavy metal contamination). Incorporating the dust removal device of the present invention into a consistent line and removing attached dust prevents the gate destruction of the MOS transistor formed on silicon and the increase in leakage current at the transistor junction. In the case where the contaminated dust is alkaline ions, it is effective in preventing deterioration of the transistor characteristics such as a change in the threshold value of the transistor. Also, since the wafer is transported in a nitrogen tunnel, it does not come into contact with atmospheric oxygen gas. For example, in dry etching of wiring aluminum, the aluminum surface is not oxidized, so that boron trichloride gas oxidizes the aluminum surface. Snow by film removal and argon ion irradiation. For the first time, it was possible to eliminate the process of removing and removing gas, and it was possible for the first time to suppress the fluctuation of the aluminum etching speed due to the influence of the oxide film on the dry etching process of simple aluminum using chlorine gas.

As a result, a semiconductor manufacturing line that can minimize the effects of dust generated in the processing tank and transport was achieved. In the present invention, it is important that the dust attached during the process is not brought into the next processing tank, and if the purpose is satisfied, a cleaning device and a dust removing device may be installed in the semiconductor manufacturing line. It can be installed at any position. Industrial applicability

According to the first aspect of the present invention, hydrogen-terminated silicon has high resistance to particulate contamination. In other words, the adhesion of fine particles is less likely to occur, and cross contamination due to back surface contamination of the silicon wafer in the semiconductor manufacturing process and re-adhesion to the back face of the silicon wafer from the transport device can be prevented.

As a result, the yield in the semiconductor production process is improved due to the reduction of contamination by fine particles, and the cost of products can be reduced.

According to the invention of claim 16, dust attached to the surface of the substrate can be removed from the surface of the substrate in the gas phase, regardless of the dust made of any material. The present invention Provides for the first time a means of removing dust in the gas phase by means of dry processing, which has been difficult, and this dry process makes it possible for the first time to automate and inline the dust removal process of semiconductor and other manufacturing equipment and semiconductor and other manufacturing lines. And the production yield can be dramatically increased.

Claims

The scope of the claims

1. In a cleaning apparatus for cleaning and drying the back surface of a substrate, means for supplying a chemical solution to the back surface of the substrate to remove an oxide film formed on the back surface, and blowing a gas containing a hydrogen active species onto the substrate surface exposed by the means. Means for terminating dangling bonds on the back surface of the substrate with the hydrogen active species.

2. At least means for supplying and cleaning a chemical solution on the surface of the substrate, and means for spraying a gas containing a hydrogen active species on the surface, wherein a dangling bond on the surface of the substrate is formed by the hydrogen active species. The cleaning according to claim 1, wherein the hydrogen is terminated.

3. The means for spraying the gas containing the hydrogen active species includes: means for activating hydrogen gas or a gas containing hydrogen gas to generate hydrogen active species; and gas containing the hydrogen active species on the back surface and / or the front surface of the substrate. The cleaning device according to claim 1, further comprising: means for supplying the cleaning liquid. -

4. The cleaning apparatus according to claim 3, wherein the gas containing hydrogen gas contains an inert gas.

5. The cleaning apparatus according to claim 4, wherein the inert gas is nitrogen gas or Z and argon gas.

6. The means for generating the hydrogen active species, wherein at least a part of a contact portion with the hydrogen gas or a gas containing hydrogen is made of a material serving as a catalyst for a hydrogen radicalization reaction. 6. The cleaning device according to any one of 5.

7. The washing according to claim 6, wherein the material serving as a catalyst contains Ni.

8. The cleaning apparatus according to claim 6, further comprising means for heating the material to be a catalyst to 300 to 450 ° C.

9. In the means for supplying a gas containing a hydrogen active species, at least a part of a contact portion with the gas containing the hydrogen active species is made of a material serving as a catalyst for a hydrogen radicalization reaction. The cleaning device according to any one of claims 3 to 8, wherein the cleaning device is any one of L and S.

10. The method according to claim 1, wherein the means for spraying a gas containing a hydrogen active species on the back surface of the base includes a gas injection nozzle at least in the vicinity of a center directly below the back surface of the base. 10. Cleaning equipment.

11. The cleaning apparatus according to any one of claims 1 to 10, further comprising means for rotating the base.

12. A semiconductor manufacturing apparatus having a substrate transport means, comprising: a treatment tank connected to the transport means, exposing a back surface of the substrate and terminating dangling bonds with hydrogen. apparatus.

13. The treatment tank that exposes the back surface of the base and terminates dangling bonds with hydrogen is the cleaning device according to any one of claims 1 to 11. Claim 12. 4. The semiconductor manufacturing apparatus according to claim 1.

14. In a semiconductor manufacturing line comprising a plurality of semiconductor processing tanks, and a substrate transport means provided in the plurality of semiconductor processing tanks, at least one processing tank for exposing the back surface of the substrate and terminating a dangling bond with hydrogen is provided. A semiconductor manufacturing line characterized by one of these.

15. The processing tank for exposing the back surface of the base and terminating dangling bonds with hydrogen is the cleaning apparatus according to any one of claims 1 to 11. 4. The semiconductor manufacturing line according to 1.

16. At least one treatment tank, means for holding a substrate in the treatment tank, means for supplying a gas having a water concentration of 100 ppb or less to the surface of the substrate, and a Bernoulli pressure difference on the surface of the substrate 16. The semiconductor manufacturing line according to claim 14, further comprising a gas-phase dust removing device comprising: means for generating dust.

17. The semiconductor manufacturing line according to claim 16, wherein the gas-phase dust removing device is provided with a means for generating an intermittent pressure fluctuation at least on the substrate surface.

18. The semiconductor manufacturing line according to claim 1, wherein a mechanism for generating a shock wave or a pressure wave is provided as means for generating the intermittent pressure fluctuation at least on the surface of the base.

19. The gas-phase dust removing apparatus according to any one of claims 16 to 18, wherein the substrate is provided with a means for setting the temperature of the substrate at a temperature of 80 ° C or more and 300 ° C or less. The semiconductor production line described in 1.

20. The semiconductor manufacturing line according to claim 19, wherein said vapor-phase dust removing device includes means for setting said substrate at a temperature of not less than 80 ° C and not more than 200 ° C.

21. The gas-phase dust removing apparatus according to claim 16, wherein the amount of water adsorbed on the surface of the substrate is not more than 2 molecular layers on average. 2. The semiconductor manufacturing line according to item 1.

22. The gas-phase dust removing apparatus, comprising: means for supplying positive and negative charges into the processing tank and removing static electricity existing in the processing tank. 21. The semiconductor manufacturing line according to any one of to 21.

23. The semiconductor manufacturing line according to any one of claims 16 to 22, wherein the vapor-phase dust removing device includes a unit for rotating the base.

24. The method according to any one of claims 16 to 23, wherein the gas-phase dust removing device has a unit for supplying ultrasonic waves or mechanical vibration or both to the substrate. Semiconductor manufacturing line.

25. The semiconductor manufacturing line according to any one of claims 16 to 24, wherein the gas-phase dust removing device includes a unit for mixing a hydrogen active species into the gas.

26. The gas-phase dust removing apparatus, further comprising means for supplying a liquid, such as liquid nitrogen, liquid argon, or isopropyl alcohol, which easily vaporizes at room temperature, to the surface of the base. 26. The semiconductor production line according to any one of 6 to 25.

27. The gas-phase dust removing apparatus according to any one of claims 16 to 26, wherein the gas is a reactive gas or a gas containing at least a reactive gas. Semiconductor manufacturing line as described.