JP3508712B2 - Resist stripping apparatus and device manufacturing method using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist stripping apparatus and a device manufacturing method using the same.

[0002]

2. Description of the Related Art In a process of manufacturing a semiconductor chip such as an LSI or a device such as a thin film transistor, the film to be processed is etched by using a resist patterned on the film to be processed formed on a device substrate as a mask, and then the resist is processed. Is often stripped using a resist stripper. In this case, as the resist stripping solution, a mixture of amine, glycol ether, water, etc. is used, and the used resist stripping solution is collected and reused. However, it is stripped (dissolved) in the resist stripper after use.
Since the formed resist is mixed, if the use time becomes long, the resist concentration in the resist stripping solution increases, the resist stripping ability deteriorates, and it becomes unusable.
In such a case, conventionally, all the resist stripping solution that is no longer worth using is replaced with a new resist stripping solution. That is, all the resist stripping liquid that is no longer worth using is discarded.

[0003]

As described above, in the prior art, since all the resist stripping solution that is no longer worth using is replaced with a new resist stripping solution, the usage time of the resist stripping solution is rather rather. There are problems that it is short, the replacement frequency is high, the operation rate is lowered, and the resist stripping solution is discarded at an early stage, resulting in high cost. An object of the present invention is to extend the use time of the resist stripping solution.

[0004]

According to a first aspect of the present invention, there is provided a resist stripping apparatus for stripping a resist using a resist stripping solution, recovering the used resist stripping solution and reusing the resist stripping solution. and pH measuring means for detecting the concentration of carbon dioxide melted into hand this pH measurement
And an amine solution replenishing means for replenishing the resist stripping solution with the amine solution based on the measurement result by the step . The invention according to claim 4 uses a resist stripping solution.
Remove the resist and collect the resist remover after use.
In a resist stripping device to be reused, resist stripping liquid
To detect the concentration of carbon dioxide dissolved in the
Conductivity measuring means for measuring the conductivity of the stripping solution, and
Resist stripping solution based on the measurement result by the electric conductivity measuring means
And an amine solution replenishing means for replenishing the amine solution with
It is a thing . According to a seventh aspect of the invention, the film to be processed is etched by using a resist patterned on the film to be processed formed on the device substrate as a mask, and then the resist is peeled off using a resist peeling liquid, the method of manufacturing a device using the resist stripping solution is recovered for reuse after use, comprising a pH measuring means for detecting the concentration of carbon dioxide melted into the resist stripping solution, the pH
An amine solution is replenished to the resist stripping solution based on the measurement result by the measuring means , and the resist stripping solution is reused while restoring the resist stripping ability of the resist stripping solution . The invention described in claim 10 is formed on a device substrate.
The patterned resist on the processed film as a mask
The processed film by etching, and then the resist
With a resist remover, and remove the resist after use.
In the method of manufacturing devices that collect and reuse syneresis
Check the concentration of carbon dioxide dissolved in the resist stripper.
Conductivity to measure the conductivity of the resist stripping solution
A measuring means is provided, and the measurement result by the conductivity measuring means is provided.
Add the amine solution to the resist stripper based on the
Reuse while restoring the resist stripping ability of Gist stripper
It is obtained by way. Then, according to this invention, focusing on the fact that the carbon dioxide in the atmosphere dissolves in the resist stripping liquid as a factor that significantly deteriorates the resist stripping ability of the resist stripping liquid, The concentration is measured by a pH measuring means or a cash register.
Measuring the conductivity measuring means for measuring the conductivity of the strike stripping solution
Since the amine solution is replenished based on this measurement result, the replenishment of the amine solution reduces the concentration of carbon dioxide in the resist stripping solution and restores the resist stripping ability of the resist stripping solution. The use time of the resist stripping solution can be extended.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic block diagram of a resist stripping apparatus according to an embodiment of the present invention. This resist stripping apparatus is a semiconductor film formed on a device substrate 21 in a manufacturing process of a semiconductor chip such as an LSI and a device such as a thin film transistor.
The device main body 1 is provided at a stage subsequent to an etching device (not shown) that etches the film 22 to be processed by using the resist 23 patterned on the film 22 to be processed such as an insulating film and a metal film as a mask. Typically, the device substrate 21 is a glass substrate, and the processed film 22 is an amorphous silicon semiconductor film or the amorphous silicon semiconductor film and an insulating film formed thereon, or formed on the insulating film. It is a metal film. A processing tank 2 is provided in the lower part of the apparatus body 1. A resist stripping solution 3 is contained in the processing tank 2. The resist stripper 3 is, for example, a monoethanolamine (ME
A), butyldiglycol (BDG), water and the like are mixed.

A processing chamber 4 is provided above the apparatus main body 1. The processing chamber 4 has a carry-in port 5 and a carry-out port 6, and a carrying roller 7 for carrying the device substrate 21 is provided between them. In this case, the floor of the processing chamber 4 is a funnel-shaped resist stripping liquid recovery part 8, and the lower part of the cylinder port of the resist stripping liquid recovery part 8 is arranged in the upper part of the processing tank 2. A plurality of showers 9 are provided above the transport rollers 7 in the processing chamber 4. Shower 9
Is connected to the lower part of the processing tank 2 via a pipe 10. A pump 11 is interposed in the pipe 10.

A replenishment tank 12 is provided outside the apparatus main body 1. In the supply tank 12, 100% ME
A high-concentration MEA solution (amine solution) 13 appropriately diluted with the A solution or water is stored. Supply tank 1
The MEA solution 13 in 2 is supplied to the processing tank 2 through the pipe 16 by driving the pump 14. The drive control of the pump 14, which will be described in detail later,
PH (pH) electrode 16 provided in the processing tank 2
The control unit 18 receives a pH signal from the pH meter 17 connected to the.

Next, description will be given of a case where the resist stripping apparatus strips the resist 23 on the device substrate 21 sent from the etching apparatus at the preceding stage. The resist stripping solution 3 in the processing tank 2 is supplied to the shower 9 through the pipe 10 by driving the pump 11. Then, the resist stripping liquid 3 is sprayed from the shower 9 onto the device substrate 21 on the transport roller 7, and the resist 23 on the device substrate 21 is dissolved and stripped. The resist stripping solution 3 containing the stripped (dissolved) resist is collected in the processing tank 2 via the resist stripping solution collecting section 8.
To be reused.

A factor that greatly deteriorates the resist stripping ability of the resist stripping solution 3 is that carbon dioxide in the atmosphere dissolves in the resist stripping solution 3. That is,
When the resist stripping solution 3 is exposed to the atmosphere in the processing chamber 4, carbon dioxide in the atmosphere dissolves in the resist stripping solution 3. Then, when the concentration of carbon dioxide dissolved in the resist stripping solution 3 becomes a certain value or more, the resist stripping ability of the resist stripping solution 3 is significantly deteriorated, and a resist residue is generated on the device substrate 21.

The concentration of carbon dioxide dissolved in the resist stripping solution 3 is inversely proportional to the pH of the resist stripping solution 3. The pH of the resist stripping solution 3 is about 12 when the resist stripping solution 3 is a new solution, but as shown in FIG. 2, it gradually decreases with the lapse of use time. When the pH of the resist stripping solution 3 is less than 10.8 to 11.2 (hereinafter, 11.0 as an example), the resist stripping ability of the resist stripping solution 3 is greatly deteriorated, and the resist residue on the device substrate 21 is reduced. Will occur.

Therefore, the processing tank 2 (or the pipe 10)
The pH of the resist stripping solution 3 in the
The H meter 17 periodically measures and the measurement result (pH signal) is sent to the control unit 18. The control unit 18 determines whether the pH value according to the pH signal supplied from the pH meter 17 is a preset value 11.0 or less, and 11.
If it is 0 or less, the pump 14 is driven. Here, the reason why the value is 11.0 or less is that it is less than 11.0,
This is because the resist residue is generated, and therefore the pump 14 is driven before the resist residue is generated.

When the pump 14 is driven, the replenishment tank 12
The MEA solution 13 therein is replenished into the processing tank 2 via the pipe 16. Then, the pH value of the resist stripping solution 3 in the processing tank 2 increases and the concentration of carbon dioxide decreases.
As a result, the resist stripping ability of the resist stripping solution 3 in the processing tank 2 is restored, so that the use time of the resist stripping solution 3 can be extended, and the operating rate can be improved and the cost can be reduced.

The pump 14 may be stopped automatically when the amount of MEA solution 13 based on the experimental data is replenished. Also, when the pH value measured by the pH meter 17 rises above the set value 11.0 by a predetermined value, for example, becomes 11.1, a stop signal is sent from the control unit 18 to the pump 14. Good.

By the way, when the pH is measured, it is necessary to calibrate the pH electrode 16, and automatic measurement is somewhat unsuitable. Further, there is a concern that potassium ions in the electrolytic solution may diffuse from the pH electrode 16 into the resist stripping solution 3. Therefore, next, another embodiment of the present invention that does not need to consider such a thing will be described.

FIG. 3 is a schematic block diagram of a resist stripping apparatus according to another embodiment of the present invention. In this figure, the same reference numerals are given to the same names as those in FIG. 1, and the description thereof will be omitted as appropriate. In this embodiment, the drive control of the pump 14 will be described in detail later, but the processing tank 2
Conductivity meter 3 connected to the conductivity electrode 31 provided inside
The control unit 18 receives the conductivity signal from the controller 2. Further, water is replenished in the processing tank 2 through a pipe 34 in which an electromagnetic valve 33 is interposed. The solenoid valve 33 is controlled by a control unit 18 which receives an absorbance signal from an absorptiometer 36 interposed in a branch pipe 35 connected in parallel to the pipe 10, which will be described in detail later.

Here, the relationship between pH and conductivity when carbon dioxide is absorbed in the new resist stripping solution 3 is as shown in FIG. As is clear from this figure, the conductivity of the resist stripping solution 3 is 16
It shows a value around 0 μS / cm, but gradually increases as the pH decreases. In this case, pH 10.8-11.
The conductivity corresponding to 2 is approximately 1300 to 600 μS / cm
And the conductivity corresponding to pH 11.0 is approximately 900μ.
S / cm.

By the way, the relationship between the water concentration (wt%) of the resist stripping solution 3 and the electrical conductivity is as shown in FIG. In this case, in FIG. 5, the top line shows the case where the pH of the resist stripping solution 3 is 10.77, the next line shows the case where the pH is 11.05, and the next line shows the pH 11.39.
And the next line is for pH 11.65,
The next line is for pH 11.85. As is clear from this figure, the conductivity of the resist stripping solution 3 gradually decreases in accordance with the decrease in the water concentration due to the evaporation of water in the resist stripping solution 3 regardless of the pH value.

Therefore, for example, as shown in FIG. 6, when the water concentration of the resist stripping solution 3 is constant, the conductivity of the resist stripping solution 3 has a correlation with pH. In this case, in FIG. 6, the black circles indicate the case where the water concentration is constant at 43%, the black squares indicate the case where the water concentration is constant at 47.4%, and the black triangles indicate the water concentration 50.4%. And constant. As a result of the above, when the conductivity was measured with the water concentration of the resist stripping solution 3 kept constant,
The value of pH is known, and thus the concentration of carbon dioxide in the resist stripping solution 3 is known. Therefore, in this embodiment,
First, it is necessary to keep the water concentration of the resist stripper 3 constant. For this purpose, it is necessary to measure the water concentration of the resist stripping solution 3. The absorptiometer 36 shown in FIG. 3 is for that purpose.

Next, the measurement of the water concentration of the resist stripping solution 3 by the absorptiometer 36 will be described. First, FIG. 7 shows the transmittance of the resist stripping solution 3 having a constant water concentration. In this case, in FIG. 7, the upper black rhombus line around the wavelength of 980 nm is the resist stripper 5
The amount of water in ml is 0 ml, the line shown by the black square in the following is the case where the amount of water in 5 ml of the resist stripper is 0.5 ml, and the line shown by the next black triangle is the resist stripper of 5 m.
The amount of water in 1 is 1 ml, and the line indicated by the black circle in the following is when the amount of water in 5 ml of the resist stripping solution is 2 ml. As is clear from this figure, there is a peak at a wavelength of 980 nm, which is due to water. Therefore, by measuring the absorbance of the resist stripping solution 3 at a wavelength of 980 nm with the absorptiometer 36, the water concentration of the resist stripping solution 3 can be obtained.

Now, the resist stripper 3 with the absorptiometer 36
The absorbance at the wavelength of 980 nm is periodically measured, and the measurement result (absorbance signal) is sent to the control unit 18. Control unit 1
8 determines whether or not the water concentration of the resist stripping solution 3 is below a certain set value based on the absorbance signal supplied from the absorptiometer 36, and if it is below a certain set value,
The electromagnetic valve 33 is opened, and water is replenished into the processing tank 2 via the pipe 34 so that the water concentration of the resist stripping solution 3 becomes a certain set value.

As described above, the conductivity of the resist stripping solution 3 in the processing tank 2 is periodically measured by the conductivity meter 32 via the conductivity electrode 31 while the water concentration of the resist stripping solution 3 is kept at a certain set value. The measurement result (conductivity signal) is sent to the control unit 18. The control unit 18 determines that the conductivity according to the conductivity signal supplied from the conductivity meter 32 substantially corresponds to a preset value, for example, pH 11.0 900.
900 μS / c is determined by determining whether or not it is μS / cm or more.
If it is m or more, the pump 14 is driven.

When the pump 14 is driven, the replenishment tank 12
The MEA solution 13 therein is replenished into the processing tank 2 via the pipe 16. Then, the conductivity of the resist stripping solution 3 in the processing tank 2 decreases, the pH value increases, and the carbon dioxide concentration decreases. As a result, the resist stripping ability of the resist stripping solution 3 in the processing tank 2 is restored, so that the use time of the resist stripping solution 3 can be extended, and the operating rate can be improved and the cost can be reduced.

The pump 14 may be stopped automatically when the MEA solution 13 in an amount based on the experimental data is replenished. Further, when the conductivity measured by the conductivity meter 32 falls below a set value of 900 μS / cm by a predetermined value, for example, 800 μS / cm, a stop signal is sent from the control unit 18 to the pump 14. May be.

[0024]

As described in the foregoing, according to the present invention, the concentration of carbon dioxide melted into the resist stripping solution,
Measures the pH measuring means or the electrical conductivity of the resist stripper.
Measured by that the conductivity measuring means, since so as to replenish the amine solution on the basis of the measurement result, the replenishment of the amine solution, the concentration of carbon dioxide in the resist stripping solution is reduced, resist peeling of the resist stripping solution The capacity is restored, and thus the usage time of the resist stripping solution can be extended.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a resist stripping apparatus according to an embodiment of the present invention.

FIG. 2 is a view showing a change with time of pH of a resist stripping solution.

FIG. 3 is a schematic configuration diagram of a resist stripping apparatus according to another embodiment of the present invention.

FIG. 4 is a diagram showing a relationship between pH and conductivity when carbon dioxide is absorbed in a new resist stripping solution.

FIG. 5 is a diagram showing the relationship between the water concentration of the resist stripping solution and the electrical conductivity.

FIG. 6 is a diagram showing a relationship between pH and electrical conductivity of a resist stripping solution having a constant water concentration.

FIG. 7 is a diagram showing the transmittance of a resist stripping solution having a constant water concentration.

[Explanation of symbols]

1 device body 2 processing tank 3 Resist stripper 4 processing room 8 Resist stripping liquid recovery section 9 showers 11 pumps 12 Supply tank 13 MEA solution 14 pumps 16 pH electrode 17 pH meter 18 Control unit 21 Device board 22 Processed film 23 Resist 31 Conductivity electrode 32 conductivity meter 33 Solenoid valve 36 Absorptiometer

Continuation of front page (56) Reference JP 2001-223153 (JP, A) JP 2000-258925 (JP, A) JP 11-133630 (JP, A) JP 10-335212 (JP, A) ) JP-A-10-83946 (JP, A) JP-A-9-219385 (JP, A) JP-A-9-213617 (JP, A) JP-A-8-241882 (JP, A) JP-A-8- 146622 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/027 G03F 7/42 H01L 21/306 H01L 21/304

Claims (13)

(57) [Claims] 1. A pH for detecting the concentration of carbon dioxide dissolved in a resist stripping solution in a resist stripping apparatus for stripping a resist using a resist stripping solution, recovering the used resist stripping solution and reusing it. Measuring means and this
A resist stripping apparatus comprising: an amine solution replenishing means for replenishing a resist stripping solution with an amine solution based on a measurement result by a pH measuring means . 2. The invention according to claim 1 , wherein the p
A resist stripping apparatus, wherein the amine solution is replenished by the amine solution replenishing means when the pH value measured by the H measuring means becomes equal to or lower than a set value. 3. The resist stripping apparatus according to claim 2 , wherein the set value is 10.8 to 11.2. 4. A resist stripping solution is used to strip the resist.
Register to collect and reuse the resist stripper after use.
In the stripping device, the two
Conduct conductivity of the resist stripper to detect the concentration of carbon oxide
Conductivity measuring means for measuring the conductivity, and this conductivity measuring means
Based on the measurement results of
A resist stripping apparatus comprising: an amine solution replenishing means for replenishing . 5. The invention according to claim 4 , further comprising a water replenishing means for measuring the water concentration of the resist stripping solution and replenishing the resist stripping solution with water so that the water concentration becomes constant. The resist stripping apparatus is characterized in that the electrical conductivity of the resist stripping solution is measured by the measuring means while the water concentration of the resist stripping solution is kept constant. 6. The resist stripping apparatus according to claim 5 , wherein the set value is 1300 to 600 μS / cm. 7. A resist after use is etched by etching the film to be processed using a resist patterned on the film to be processed formed on a device substrate as a mask, and then peeling the resist using a resist peeling solution. In a device manufacturing method in which the stripping solution is collected and reused , p for detecting the concentration of carbon dioxide dissolved in the resist stripping solution is used.
A method for manufacturing a device, comprising: an H measuring means , wherein the amine solution is replenished to the resist stripping solution based on the measurement result by the pH measuring means and the resist stripping solution is reused while restoring the resist stripping ability. 8. The method of manufacturing a device according to claim 7 , wherein the amine solution is replenished when the measured pH value becomes equal to or lower than a set value. 9. The device manufacturing method according to claim 8 , wherein the set value is 10.8 to 11.2. 10. A processed film formed on a device substrate.
The resist patterned above is used as a mask to form the target.
Etching the processed film, and then removing the resist
Strip using a stripper and collect the resist stripper after use
In a device manufacturing method for reuse after reuse
To detect the concentration of carbon dioxide dissolved in the stripper,
Equipped with conductivity measuring means to measure the conductivity of the resist stripper
Eh, based on the measurement result by this conductivity measuring means
Amine solution is replenished to the resist stripper to remove the resist stripper.
A method for manufacturing a device, wherein the device is reused while restoring the resist stripping ability of the device. 11. The invention according to claim 10 , wherein the electrical conductivity of the resist stripping solution is measured by measuring the water concentration of the resist stripping solution and supplying water so that the water concentration becomes constant. A method for manufacturing a device, which is characterized by being performed. 12. The method of manufacturing a device according to claim 11 , wherein the amine solution is replenished when the measured conductivity becomes equal to or higher than a set value. 13. The device manufacturing method according to claim 12 , wherein the set value is 1300 to 600 μS / cm.