JP2003068691A - Semiconductor substrate cleaning method and semiconductor substrate cleaning system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in a removing liquid spraying type polymer removing method in a conventional technique, of the difficulty in removing a residual substance, after dry etching completely and this substance degrades the removing performance of the removing liquid and causes the generation of particles resulting in concerned deterioration of the production yield. SOLUTION: In this method, functional water such as ozone water or hydrogen water is used, and each chemical liquid discharge spray body 6 is provided with an ultrasonic vibration propagating bar 2, thereby adding a physical performance for removing polymer with ultrasonic energy, in addition to a chemical removing performance with a chemical liquid, and thus, the polymer-removing performance can be improved. Also, by making ultrasonic vibration propagate to a chemical liquid having performance of removing an organic matter or a metal, this performance which the functional water such as ozone water or hydrogen water has, thereby can improve the particle removal performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor substrate cleaning method and a semiconductor substrate cleaning apparatus suitable for removing reaction products after dry etching in the manufacture of semiconductor products.

[0002]

2. Description of the Related Art Conventionally, since a CF type process gas is used in a semiconductor manufacturing process, particularly in a contact dry etching of an interlayer insulating film for electrically connecting wiring layers, a reaction generation of an etching gas and an insulating film material is performed. The product remained as a carbon-rich CF-based polymer in the contact after the contact dry etching. In order to remove the polymer after such dry etching, for example, a semiconductor substrate is set in a chamber of a cleaning device having a hydrofluoric acid-based stripping solution spray nozzle and a rinse pure water spray nozzle, and a wafer cassette is set at a low speed. While rotating, a hydrofluoric acid-based stripping solution was sprayed to remove the polymer, and then pure water was sprayed to rinse the stripping solution.

FIG. 3 is a schematic cross-sectional view of a conventional spray type semiconductor substrate cleaning apparatus capable of supplying a chemical liquid and pure water for chemical liquid rinsing into the chamber for peeling and cleaning. This spray type semiconductor substrate cleaning apparatus has a cylindrical shape, and 19 is a stripping solution spraying section, 20 is a spraying section for pure water for stripping solution rinsing, and 2
Reference numeral 1 is a retainer for fixing a semiconductor substrate, 22 is a rotatable substrate cassette installation plate, 23 is a semiconductor substrate, 24 is a chamber, and 25 is a substrate cassette for vertically arranging and supporting substrates.

FIG. 4 is a schematic view of the spray portions 19 and 20 shown in FIG. The spray nozzle 18 shown in FIG. 4 is attached to the outer surface of the chamber 24 shown in FIG. 3 (see FIG. 3), and the spray unit body 16 has the shape of an elongated pipe.
A large number of spray nozzles 18 (pure water nozzles in the case of pure water spray) are installed on the side surface, and the chemical liquid that has entered the spray unit main body 16 from the chemical liquid supply unit 17 is sprayed from here. There is.

The operation of removing the polymer, which is the reaction product after dry etching, using the spray type semiconductor substrate cleaning apparatus configured as described above will be described. Substrate cassette 25 containing semiconductor substrate 23 that has been dry-etched
Is set on the substrate cassette installation plate 22, and thereafter the processing is started. First, the hydrofluoric acid-based stripping solution under pressure is sprayed from the spray nozzle 18 of the stripping solution spraying section 19 to start the polymer removal. At this time, the substrate cassette installation plate 22 is rotating at a low speed of 30 rpm to 50 rpm. After a predetermined processing time, the spraying of the hydrofluoric acid-based stripping solution is stopped, the substrate cassette installation plate 22 is rotated at a medium speed of 600 rpm, and the rinse is pressurized by the spray nozzle 18 of the spray unit 20 of the rinse pure water. Pure water is sprayed to remove the hydrofluoric acid-based peeling liquid adhering to the semiconductor substrate 23. Next, the substrate cassette installation plate 22 is set to 20
The speed is increased to 00 rpm, N ₂ gas is sprayed, and the semiconductor substrate 23
To dry.

[0006]

SUMMARY OF THE INVENTION In the above-described spray-type polymer removing method of a pressurized stripping solution, residues such as a polymer adhering to the surface of a semiconductor substrate after dry etching are completely removed. In particular, in the case of a polymer, which is a reaction product formed inside the contact, this residue remains on the surface of the semiconductor substrate and becomes an obstacle, so that the stripping solution hardly penetrates into the contact. Therefore, there is a problem that the removal performance of the polymer is hindered by the residue, and the residue becomes a factor of generating particles, which may cause a decrease in yield.

An object of the present invention is to provide a semiconductor substrate cleaning method and a semiconductor substrate cleaning apparatus capable of solving the above-mentioned problems of polymer removing performance and particle removing performance and improving the yield.

[0008]

In order to solve the above problems, a method for cleaning a semiconductor substrate according to claim 1 comprises a first step of spraying functional water onto the semiconductor substrate, and a hydrofluoric acid chemical solution on the semiconductor substrate. Is sprayed, and a third step of spraying pure water on the semiconductor substrate is included.

According to the first aspect of the present invention, since functional water having a high cleaning ability is used, it is suitable for efficiently removing residues and particles due to the reaction products generated on the surface of the semiconductor substrate in the dry etching process. ing. After removing the residue by the first step, the peelable hydrofluoric acid-based chemical can easily enter the inside of the contact without disturbing the residue. It becomes possible to remove the polymer generated in. As a result, the yield can be improved. By this method, it is possible to reduce the deterioration of the quality of the semiconductor product due to the polymer removal step and realize the manufacture of the semiconductor product with excellent reproducibility.

According to a second aspect of the present invention, there is provided a method of cleaning a semiconductor substrate according to the first aspect, wherein at least one of functional water, hydrofluoric acid-based chemical solution or pure water is sprayed while applying ultrasonic energy. Is characterized by.

According to the second aspect of the present invention, in addition to exhibiting the same effects as the first aspect of the invention, the polymer removing performance and the particle removing performance can be obtained by adding the physical removing performance by ultrasonic energy. Etc. can be improved, and as a result, the yield can be improved.

A method of cleaning a semiconductor substrate according to a third aspect is the method of cleaning a semiconductor substrate according to the second aspect, wherein the ultrasonic wave is
It is characterized by a frequency of 1.5 MHz and an output of 20 W to 30 W.

According to the invention of claim 3, the same effect as that of the invention of claim 2 is exhibited, and the output of ultrasonic waves is made weaker than the output used in normal semiconductor cleaning. Polymer removal performance and particle removal performance can be improved without adversely affecting the pattern formed on the substrate, and as a result, the yield can be improved.

The method for cleaning a semiconductor substrate according to claim 4 is the method for cleaning a semiconductor substrate according to claim 1, 2 or 3, characterized in that the semiconductor substrate is dry-etched.

According to the invention described in claim 4,
The same effect as the invention described in 2 or 3 is exhibited.

According to another aspect of the semiconductor substrate cleaning apparatus of the present invention, a semiconductor substrate installation section, a first spray section for spraying functional water toward the semiconductor substrate installation section, and a second spray section for spraying a hydrofluoric acid chemical solution. It is characterized by having a spray section and a third spray section for spraying pure water.

According to the fifth aspect of the present invention, since the first spraying section for spraying the functional water is provided, residues and particles due to the reaction product generated on the surface of the semiconductor substrate in the dry etching step are treated as the functional water. Suitable for efficient removal by. Further, since the second spraying section for spraying the hydrofluoric acid-based chemical is provided, after the residue is removed, the peelable hydrofluoric acid-based chemical can be easily penetrated into the contact or the like without disturbing the residue. Therefore, the polymer generated inside the contact or the like in the dry etching step can be removed. As a result, the yield can be improved. By this method, it is possible to reduce the deterioration of the quality of the semiconductor product due to the polymer removal step and realize the manufacture of the semiconductor product with excellent reproducibility.

A semiconductor substrate cleaning apparatus according to a sixth aspect is the semiconductor substrate cleaning apparatus according to the fifth aspect, wherein the first and second semiconductor substrate cleaning apparatuses are provided.
Alternatively, at least one of the third spraying sections is provided with ultrasonic vibration transmitting means.

According to the sixth aspect of the present invention, the same effect as that of the fifth aspect of the invention is exhibited, and since the ultrasonic vibration propagating means is provided, the physical removal performance by the ultrasonic energy is improved. Since it can be added, the polymer removal performance and the particle removal performance can be improved, and as a result, the yield can be improved.

A semiconductor substrate cleaning apparatus according to a seventh aspect is the semiconductor substrate cleaning apparatus according to the sixth aspect, wherein the ultrasonic vibration propagating means is built in the first, second or third spraying section. Characterize.

According to the invention of claim 7, in addition to exhibiting the same effect as the invention of claim 6, since the ultrasonic wave propagating means is incorporated in the spraying section, the energy of ultrasonic wave is efficiently transferred to the chemical liquid. And so on. It is also possible to adjust the physical action on the actual wafer.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of a spraying unit attached to the spraying type semiconductor substrate cleaning apparatus of the present invention. In FIG. 1, 1 is a chemical liquid line in the spray unit main body, 2
Is an ultrasonic wave transmission rod for transmitting ultrasonic waves to the chemical liquid, 3 is an ultrasonic wave generation device, 4 is a chemical liquid line for supplying the chemical liquid, and 5 is a semiconductor substrate placed below the spraying section and arranged in parallel in the vertical direction.
Reference numeral 6 is a spray unit main body, and 7 is a spray nozzle for spraying a chemical solution or the like onto a semiconductor substrate.

FIG. 2 is a schematic sectional view of the spray type semiconductor cleaning apparatus of the present invention. In FIG. 2, 8 is a hydrofluoric acid-based stripping liquid spraying unit, 9 is a functional water spraying unit such as ozone water (dissolved ozone water), 10 is a pure water spraying unit for rinsing, 11 is a retainer ring for supporting a semiconductor substrate, and 12 is a rotation. A possible substrate cassette installation plate, 13 is a chamber, and 14 is a semiconductor substrate cassette. To further explain functional water, gas is added to ultrapure water.
(O ₃ , H ₂ , chlorine) is dissolved to have oxidizing and reducing properties, or a small amount of acid or alkali is added to this gas-dissolved water to adjust the pH, and the water has high cleaning ability. In FIG. 2, the spray unit main body 6 shown in FIG.
They are attached at positions 9 and 10 so that the longitudinal direction is perpendicular to the paper surface. This spray type semiconductor substrate cleaning device
By mounting the spray nozzle 7 shown in FIG. 1 on the side wall of the chamber body, it is a spray type semiconductor substrate cleaning apparatus that can apply physical energy by ultrasonic waves to chemicals and chemical rinses, and can be used for polymer removal etc. Suitable for 8 inch size.

Next, the operation of removing the reaction product after dry etching using the spray type semiconductor substrate cleaning apparatus of the present invention will be outlined. First, when the chemical solution is sprayed onto the semiconductor substrate 5 from the spray sections 8, 9 and 10, the chemical solution is supplied from the chemical solution line 4 to the spray section body 6. At this time, the ultrasonic generator 3
Thereby, the ultrasonic wave propagates to the drug solution via the ultrasonic wave propagation rod 2. The purpose of the ultrasonic wave propagation rod 2 is to spray the chemical liquid and the rinse water to which the energy is uniformly given by the ultrasonic vibration to the wafers in the batch, and therefore, rod-shaped quartz is used. By the propagation of this ultrasonic vibration,
The chemical liquid has the energy of ultrasonic vibration, jumps out from the spray nozzle 7, and reaches the semiconductor substrate 5. The ultrasonic frequency at this time is a frequency of 1.5 MHz in consideration of the influence on the pattern formed on the substrate, and is 20 W to 30 W, which is weaker than the ultrasonic output normally used in a scrubber for cleaning semiconductors.
It is best to process in. By this method, the chemical solution has the energy of ultrasonic vibration, so that the reaction product removal performance and residue polymer removal performance on the surface of the semiconductor substrate are significantly improved as compared with the conventional case without ultrasonic vibration. .

The operation of the spray type semiconductor substrate cleaning apparatus according to the present embodiment will be described in detail. Ultrasonic vibration energy is applied to the semiconductor substrate 5 after dry etching, and pressurized ozone water is supplied from the spray section 9. Spray to remove residue. At this time, the substrate cassette installation plate 12 rotates the semiconductor substrate 5 at a low speed of 30 to 50 rpm by a rotating rotor.
It is rotating at a medium speed of 00 rpm. Repeat this several times. Next, ultrasonic vibration energy is also applied, and a hydrofluoric acid-based stripping solution under pressure is sprayed from the spraying section 8 to remove the polymer. Here, the hydrofluoric acid-based stripping solution is an organic stripping solution obtained by adding 1 to 10 wt% of HF to an amine-based stripping solution.
At this time, the rotating rotor moves the semiconductor substrate 5 from 30 rpm to 50 rpm.
It is rotating at a low speed of rpm and a medium speed of 600 rpm.
Repeat this several times. This completely removes the polymer residuals by chemical and physical action.

After that, the same ultrasonic pure energy as the chemical liquid is applied and pressurized pure water for rinsing is sprayed on the spray section 10.
Further spraying is performed to completely remove the hydrofluoric acid-based stripping solution adhering to the semiconductor substrate 5. After that, rotate the rotor to 2000
The semiconductor substrate 5 is dried by spraying N ₂ gas while rotating at high speed of rpm. In this apparatus, since the semiconductor substrate 5 is rotated around the center of the substrate, the retainer ring 11 is provided at the time of setting the substrate, which enables swift rotation and processing centered on the center of the substrate.

In this method, ultrasonic waves are applied to the chemical solution and treatment with functional water having a high cleaning ability is performed to remove the residue adhering to the substrate surface after the dry etching and then remove the polymer generated by the dry etching. So, for example,
The polymer generated inside the contact hole with a high aspect ratio can be removed without the stripping solution being blocked by the residue, and the polymer removal performance by the hydrofluoric acid-based stripping solution can be improved. In addition, since ultrasonic waves are used for rinsing the chemical liquid, particle removal performance can be improved and yield can be improved.

Note that ultrasonic energy may be applied to at least one of the functional water, the hydrofluoric acid type chemical solution, and the pure water.

[0029]

According to the first aspect of the present invention, since functional water having a high cleaning ability is used, residues and particles due to the reaction products generated on the surface of the semiconductor substrate in the dry etching step can be efficiently removed. Suitable for After removing the residue by the first step, the peelable hydrofluoric acid-based chemical can easily enter the inside of the contact without disturbing the residue. It becomes possible to remove the polymer generated in. As a result, the yield can be improved. By this method, it is possible to reduce the deterioration of the quality of the semiconductor product due to the polymer removal step and realize the manufacture of the semiconductor product with excellent reproducibility.

According to the invention of claim 2, in addition to exhibiting the same effect as that of the invention of claim 1, polymer removal performance and particle removal performance are obtained by adding physical removal performance by ultrasonic energy. Etc. can be improved, and as a result, the yield can be improved.

According to the third aspect of the invention, the same effect as that of the second aspect of the invention is exhibited, and the output of ultrasonic waves is made weaker than the output used in normal semiconductor cleaning. Polymer removal performance and particle removal performance can be improved without adversely affecting the pattern formed on the substrate, and as a result, the yield can be improved.

According to the invention of claim 4, claim 1,
The same effect as the invention described in 2 or 3 is exhibited.

According to the fifth aspect of the present invention, since the first spraying section for spraying the functional water is provided, residues and particles due to the reaction product generated on the surface of the semiconductor substrate in the dry etching step are treated as the functional water. Suitable for efficient removal by. Further, since the second spraying section for spraying the hydrofluoric acid-based chemical is provided, after the residue is removed, the peelable hydrofluoric acid-based chemical can be easily penetrated into the contact without disturbing the residue. Therefore, the polymer generated inside the contact or the like in the dry etching step can be removed. As a result, the yield can be improved. By this method, it is possible to reduce the deterioration of the quality of the semiconductor product due to the polymer removal step and realize the manufacture of the semiconductor product with excellent reproducibility.

According to the invention described in claim 6, in addition to exhibiting the same effect as the invention described in claim 5, the ultrasonic vibration propagating means is provided, whereby the physical removal performance by ultrasonic energy is improved. Since it can be added, the polymer removal performance and the particle removal performance can be improved, and as a result, the yield can be improved.

According to the invention described in claim 7, in addition to exhibiting the same effect as the invention described in claim 6, since the ultrasonic wave propagating means is incorporated in the spray section, the ultrasonic wave energy is efficiently transferred to the chemical liquid. And so on. It is also possible to adjust the physical action on the actual wafer.

[Brief description of drawings]

FIG. 1 is a schematic view of a spray unit of a semiconductor substrate cleaning apparatus according to this embodiment.

FIG. 2 is a schematic sectional view of the semiconductor substrate cleaning apparatus according to the present embodiment.

FIG. 3 is a schematic sectional view of a semiconductor substrate cleaning apparatus in a conventional example.

FIG. 4 is a schematic view of a spray unit of a semiconductor substrate cleaning apparatus in a conventional example.

[Explanation of symbols]

1 Chemical liquid line in the spray unit body 2 Ultrasonic propagation rod 3 Ultrasonic generator 4 Chemical line 5 Semiconductor substrate 6 spray unit body 7 spray nozzle 8 Hydrofluoric acid-based stripping solution sprayer 9 Ozone water and other functional water sprayers 10 Pure water spray for rinsing 11 Retainer ring 12 Substrate cassette installation plate 13 chambers 14 Semiconductor substrate cassette 16 Spray unit body 17 Chemical supply unit 18 spray nozzle 19 Stripping solution sprayer 20 Pure water spray for rinsing 21 retainer 22 Substrate cassette installation plate 23 Semiconductor substrate 24 chambers 25 board cassette

Claims (7)

[Claims] 1. A first step of spraying functional water onto a semiconductor substrate, a second step of spraying a hydrofluoric acid-based chemical solution onto the semiconductor substrate, and a third step of spraying pure water onto the semiconductor substrate. A method for cleaning a semiconductor substrate, comprising: 2. The method of cleaning a semiconductor substrate according to claim 1, wherein at least one of the functional water, the hydrofluoric acid-based chemical solution, and the pure water is sprayed while applying ultrasonic energy. 3. The ultrasonic wave has a frequency of 1.5 MHz and an output of 20.
The semiconductor substrate cleaning method according to claim 2, wherein W to 30 W. 4. The semiconductor substrate, which has been dry-etched, according to claim 1, 2, or 3.
The method for cleaning a semiconductor substrate described. 5. A semiconductor substrate installation section, a first spray section for spraying functional water toward the semiconductor substrate installation section, a second spray section for spraying a hydrofluoric acid based chemical solution, and pure water spray A semiconductor substrate cleaning apparatus having a third spraying section. 6. The semiconductor substrate cleaning apparatus according to claim 5, wherein at least one of the first, second or third spraying section is provided with ultrasonic vibration transfer means. 7. The ultrasonic vibration propagation means comprises the first and second ultrasonic wave propagation means.
7. The semiconductor substrate cleaning apparatus according to claim 6, which is incorporated in the third spray unit.