JP2000100684A - Method and device treating substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily confirm the fact that an upper layer film is totally removed, for a specified substrate treatment to be performed with no trouble thereafter. SOLUTION: Related to a device wherein a substrate W where an upper layer anti-reflection film is formed on a photo-resist film is supplied with a pure water as a rinsing liquid to remove the upper layer anti-reflection film followed by development process, a waste-liquid pipe 5 in which a waste rinse liquid flows is provided with a PH measuring device 13 for measuring PH of the waste rinse liquid with specified interval. When the upper layer anti- reflection film of the substrate W is totally removed, the PH of the waste rinse liquid does not change. Based upon this, a main controller 10 stops supplying the rinse liquid and discharges a developer onto the substrate W from a developer discharge nozzle 7. Even if the film thickness of the upper layer anti-reflection film fluctuates, the upper layer anti-reflection film is surely removed with a minimum required rinse liquid, for development process with no trouble thereafter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for processing a substrate such as a semiconductor wafer, and more particularly to an upper antireflection film (TARC: Top) formed on a photoresist film.
The present invention relates to detection of an end point of a removal process in a process of removing an upper layer film such as an anti-reflection coating.

[0002]

2. Description of the Related Art Conventionally, when a circuit pattern or the like is exposed on a substrate such as a semiconductor wafer, a lower layer is formed between the photoresist film and the substrate to reduce standing waves and halation generated in the photoresist film. Anti-reflective coating (BARC: Botto
m Anti Reflecting Coating) or an upper anti-reflection coating (TARC), which is also effective as an environmental protection film, is formed on the photoresist film.

[0003] The upper antireflection film is water-soluble, and the dissolved liquid shows acidity. On the other hand, in the development of the photoresist film after exposure, the chemical reaction between acid and alkali is used. Therefore, unless the upper antireflection film is completely removed before the development, The developing solution reacts with the acidic solution of the upper antireflection film, causing a change in the concentration of the developing solution, thereby lowering the patterning accuracy. In addition, when developing with a developing solution on the substrate, if the upper anti-reflection film remains, the developing solution is repelled to cause development defects.

Therefore, conventionally, pure water or a developing solution is discharged onto the substrate before the development processing to remove the upper antireflection film. Specifically, it is difficult to determine whether or not the upper anti-reflection film has been completely removed from the surface state of the substrate or the like. Liquid (hereinafter referred to as “rinse liquid”)
In order to optimize the supply conditions, the substrate actually processed under the conditions is subjected to a development process.
The line width evaluation confirms the suitability of the conditions.

[0005]

However, the method of setting the rinsing liquid supply conditions as described above is an extremely complicated operation. In addition, considering the fluctuation of the thickness of the upper anti-reflection film, etc., the supply conditions of the rinsing liquid should be set to a safe side, that is, the flow rate of the rinsing liquid should be set to a higher value, or the supply time should be set longer. It is necessary to keep. As a result, problems such as an unreasonable increase in the supply amount of the rinsing liquid and an increase in processing time occur. Further, if the thickness of the upper anti-reflection film is changed according to the type of the substrate, etc., the supply condition of the rinsing liquid must be reset, and the management of the process becomes complicated.

The present invention has been made in view of such circumstances, and it is possible to easily confirm that an upper layer film has been completely removed, and to perform a predetermined substrate processing without any trouble. An object of the present invention is to provide a substrate processing method and an apparatus therefor.

[0007]

The present invention has the following configuration in order to achieve the above object. That is, the invention according to claim 1 is a substrate processing method for performing a predetermined process on a substrate after dissolving and removing an upper layer film formed on a substrate with a rinsing liquid, wherein the rinsing liquid is applied to the substrate on which the upper layer film is formed. By supplying flowing water, by measuring the hydrogen ion concentration of the drainage water of the rinse liquid in which the upper film is dissolved,
It is characterized in that it is determined that the upper layer film has been dissolved and removed, and the process proceeds to a predetermined process thereafter.

According to a second aspect of the present invention, in the substrate processing method of the first aspect, the upper layer film is an upper anti-reflection film formed on a photoresist film on the substrate,
It is determined that the upper antireflection film has been dissolved and removed by running rinse water, and the process proceeds to a subsequent development process.

According to a third aspect of the present invention, there is provided a rinsing device for supplying a rinse water for dissolving and removing the upper anti-reflection film to a substrate on which at least a photoresist film and an upper anti-reflection film are formed in this order. A liquid supply means, a developer supply means for supplying a developer to the substrate from which the upper antireflection film has been removed, and a measurement means for measuring the hydrogen ion concentration of the effluent of the rinse liquid in which the upper antireflection film has been dissolved; And control means for switching from supply of the rinsing liquid to supply of the developer based on the measurement result of the measurement means.

According to a fourth aspect of the present invention, in the substrate processing apparatus according to the third aspect, the measuring means is a pH measuring device provided in a drainage flow path of the rinsing liquid.

According to a fifth aspect of the present invention, in the substrate processing apparatus according to the third aspect, the measuring means is an electric conductivity measuring device provided in a drainage flow path of the rinsing liquid.

According to a sixth aspect of the present invention, in the substrate processing apparatus according to any one of the third to fifth aspects, the developing solution supply means supplies the developing solution onto the substrate in a liquid state.

According to a seventh aspect of the present invention, in the substrate processing apparatus according to any one of the third to sixth aspects, the control means controls the upper surface of the substrate processing apparatus while the rinsing liquid supply means supplies the rinsing liquid flowing water to the substrate. The hydrogen ion concentration of the effluent of the rinse liquid in which the anti-reflection film was dissolved was sequentially measured at predetermined time intervals, and based on the fact that the difference between the temporally successive measurement results became substantially zero, The operation is switched from the supply to the supply of the developer.

[0014]

The operation of the first aspect of the invention is as follows. When the upper film exhibits a change in the hydrogen ion concentration according to the amount of the upper film dissolved in the rinsing liquid, the rinsing liquid drainage is performed by measuring and monitoring the hydrogen ion concentration of the rinsing liquid effluent. The amount of dissolved upper layer film contained in running water can be known. That is, in the process of removing the upper film by supplying running water of a rinsing liquid to the substrate on which the upper film has been formed,
At first, the amount of dissolved upper layer film contained in the effluent of the rinsing liquid is large, so the hydrogen ion concentration of the rinsing liquid effluent is strongly affected by the dissolved substance of the upper layer film. As the upper upper film decreases, the influence on the hydrogen ion concentration by the dissolved substance of the upper film decreases. Then, after the upper layer film on the substrate is completely removed, the rinsing liquid discharged from the rinsing liquid has no change in the hydrogen ion concentration, and exhibits the original hydrogen ion concentration of the rinsing liquid. By measuring the hydrogen ion concentration of the effluent of the rinsing liquid in which the upper film has been dissolved in this way, it can be determined that the upper film has been dissolved and removed. Can move on to substrate processing.

The operation of the invention described in claim 2 is as follows. The upper antireflection film formed on the photoresist film is water-soluble, and the dissolved liquid is acidic. Therefore, from the hydrogen ion concentration of the effluent of the rinse liquid,
The acidity of the effluent can be known. During the beginning of the upper anti-reflection coating removal process, the drainage water of the rinsing liquid is
It shows a relatively strong acidity under the influence of the dissolved upper antireflection film, but as the upper antireflection film on the substrate is removed, the acidity of the effluent of the rinse liquid changes to the alkali side. After the upper anti-reflection film on the substrate is completely removed, the acidity of the rinsing liquid does not change, and the original acidity of the rinsing liquid is exhibited. In the invention of claim 2, the end point of the removal processing of the upper antireflection film is determined by paying attention to the acidity of the drainage water of the rinse liquid, and the process proceeds to the next development processing.

The operation of the invention described in claim 3 is as follows. First, the rinsing liquid supply means supplies rinsing liquid running water onto the substrate to start the removal processing of the upper antireflection film on the substrate. During the removal process, the measuring means measures the hydrogen ion concentration of the effluent of the rinse liquid in which the upper antireflection film has been dissolved. The measurement result is given to the control means. When the upper anti-reflection film on the substrate is completely removed, the hydrogen ion concentration of the rinsing liquid does not change. Thereby, the control means determines that the upper antireflection film on the substrate has been removed, and switches from supplying the rinsing liquid to supplying the developing liquid. In accordance with a command from the control unit, the developing solution is supplied from the developing solution supply unit onto the substrate from which the upper antireflection film has been removed, and the developing process is performed.

According to the fourth aspect of the present invention, the PH measuring device provided in the rinse liquid drain passage measures the PH equivalent to the hydrogen ion concentration, and gives the result to the control means.

According to the fifth aspect of the present invention, the electric conductivity measuring device provided in the drainage channel for the rinsing liquid measures the electric conductivity equivalent to the hydrogen ion concentration, and the result is sent to the control means. give.

According to the sixth aspect of the present invention, the developing solution supply means supplies the developing solution in a liquid state on the substrate from which the upper antireflection film has been removed, and performs static development in that state.

The operation of the invention described in claim 7 is as follows. As described above, as the upper anti-reflection film on the substrate is removed by the flowing water of the rinsing liquid, the amount of change in the hydrogen ion concentration of the discharged water of the rinsing liquid gradually decreases,
After the upper antireflection film is completely removed, the hydrogen ion concentration of the effluent of the rinse liquid becomes constant. Therefore, the control means sequentially measures the hydrogen ion concentration of the rinsing liquid flowing water at predetermined time intervals in the process of removing the upper anti-reflection film, and the difference between the temporally successive measurement results becomes substantially zero. Based on that, it is determined that the upper anti-reflection film has been removed,
The supply is switched from the supply of the rinse liquid to the supply of the developer.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a development processing apparatus which is an embodiment of the substrate processing apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes a spin chuck that suction-holds a substrate W such as a semiconductor wafer to be processed. The spin chuck 1 is connected to an output shaft of a motor 2. A cup 3 is provided around the spin chuck 1 to prevent a rinsing liquid (pure water in this embodiment) or a developer from scattering. An exhaust pipe 4 for exhausting the inside of the cup 3 and a drain pipe 5 for discharging the waste liquid collected by the cup 3 are connected to the bottom of the cup 3, respectively.

A rinse liquid discharge nozzle 6 for discharging a rinse liquid and a developer discharge nozzle 7 for discharging a developer are provided beside the cup 3. Each of the nozzles 6 and 7 is configured to be movable between a standby position outside the cup 3 and a position above the rotation center of the substrate W. Rinse liquid discharge nozzle 6
Represents a rinsing liquid supply unit in the apparatus of the present invention, and the developer discharge nozzle 7 corresponds to a developer supply unit in the apparatus of the present invention. An on-off valve 8 is interposed in the rinsing liquid supply passage communicating with the rinsing liquid discharge nozzle 6. This on-off valve 8
Is controlled by a command given from the main controller 10 via the rinse liquid discharge controller 9. Similarly, an opening / closing valve 11 is interposed in the developer supply path communicating with the developer discharge nozzle 7. The on-off valve 11 is connected to the main controller 1 via a developer discharge controller 12.
It is controlled by a command given from 0.

Further, a pH measuring device 13 for measuring the pH (pH) of the drainage flow of the rinsing liquid is provided in the drainage flow path in the drainage pipe 5 of the cup 3. This PH measuring device 13
Corresponds to the measuring means in the apparatus of the present invention. The measurement result obtained by the PH measuring device 13 is given to the main controller 10. The main controller 10 controls the on-off valves 8 and 11 based on the measurement result. The main controller 10 controls the rotation of the motor 2 via the spin controller 14. This main controller 1
0 corresponds to control means in the device of the present invention.

Next, the operation of the developing apparatus having the above-described configuration will be described with reference to the flowchart of FIG. First, a substrate W to be processed is carried into the present apparatus and is suction-held on the spin chuck 1. This substrate W is shown in FIG.
As shown in (a), a lower antireflection film (BAR
C), photoresist film (PR), upper anti-reflective coating (TARC)
Are stacked in that order. In applying the present invention, at least a photoresist film and an upper antireflection film need only be formed on the substrate W, and the lower antireflection film is not necessarily formed.

When the substrate W is held by suction on the spin chuck 1, the spin chuck 1 is driven to rotate at a predetermined number of rotations, and the rinsing liquid discharge nozzle 6 moves from the standby position to above the rotation center of the substrate W. . Then, the opening / closing valve 8 is opened and the flowing water of the rinsing liquid (pure water) is supplied onto the substrate W, whereby the removal processing of the upper antireflection film starts (step S1).

When the removal treatment of the upper antireflection film starts, P
The H measuring device 13 measures the PH of the effluent of the rinsing liquid flowing through the drain pipe 5 every predetermined time Δt (for example, 0.1 seconds), and sequentially gives the measurement results to the main controller 10 (step S2). ). As described above, the solution in which the upper anti-reflection film is dissolved is acidic. Therefore, when the removal treatment of the upper anti-reflection film is started, as shown in FIG. To position. As the upper anti-reflection film of the substrate W is removed, the amount of dissolution of the upper anti-reflection film contained in the drainage water of the rinsing liquid decreases,
The pH of the effluent of the rinsing liquid moves to the alkaline side (in this embodiment, the rinsing liquid is pure water and neutral, so it can be said to be neutral). When the remaining amount of the upper anti-reflection film on the substrate W decreases, the amount of change in PH also decreases, and after the upper anti-reflection film is completely removed, the pH of the rinsing liquid drainage water is reduced.
Ceases to change and becomes the original PH of the rinsing liquid (in this case, neutral and PH = 7).

The main controller 10 having given the PH measurement result of the rinsing drainage water at predetermined time intervals Δt,
The difference ΔPH between the measurement results that are successive in time is calculated, and it is determined whether or not the difference ΔPH has become substantially zero (step S3). If ΔPH is not zero, that is, has changed, it is determined that the upper antireflection film of the substrate W still remains, and the supply of the rinsing liquid is continued. On the other hand, when ΔPH becomes substantially zero, it is determined that the upper antireflection film of the substrate W has been completely removed, and the process proceeds to step S4, where the on-off valve 8 is closed to stop the supply of the rinsing liquid (step S4). S4).
FIG. 2B shows the substrate W when the upper antireflection film is removed.
Is shown. For the sake of safety, when the state of ΔPH ≒ 0 occurs continuously for a predetermined number of times, it is determined that the upper antireflection film has been completely removed, and step S
4 may be performed.

When the removal processing of the upper antireflection film is completed, the process proceeds to the next development processing (step S5). Specifically, the rinse liquid discharge nozzle 6 returns to the standby position, and the developer discharge nozzle 7 advances above the rotation center of the substrate W. While the substrate W is being rotated at a low speed, the opening / closing valve 11 is opened for a predetermined time to discharge a predetermined amount of the developing solution from the developing solution discharge nozzle 7 to fill the developing solution DL onto the substrate W (FIG. c)). When the developer is filled, the rotation of the substrate W is stopped,
In this state, a static development process is performed for a predetermined time. During the developing process, the developer discharge nozzle 7 returns to the standby position, and the rinse liquid discharge nozzle 6 advances again above the rotation center of the substrate W. When the developing process is completed, the spin chuck 1 rotates at a high speed to shake off the developing solution on the substrate W, and a rinsing liquid (pure water) is supplied from a rinsing liquid discharge nozzle 6 to remove the developing solution residue on the surface of the substrate W. Is replaced by pure water. When the supply of the rinsing liquid for a predetermined time is completed, the substrate W is rotated at a high speed as it is, the rinsing liquid is shaken off from the substrate W, and the substrate W is dried. The developed substrate W is carried out of the apparatus, the next substrate W is carried in the apparatus, and the same processing is repeated thereafter.

As described above, according to the present embodiment, the PH of the rinsing liquid is monitored, and the point in time at which the change in PH has ceased is determined to be the end point of the removal processing of the upper antireflection film. Since the process is shifted to the next development process, even if the thickness of the upper anti-reflection film varies or is changed, there is no need to reset the rinsing liquid supply condition, and the upper anti-reflection film is prevented. The film can be reliably removed.

The present invention is not limited to the above-described embodiment.
Modifications can be made as follows. (1) The rinse liquid is not limited to pure water, and may be another liquid. For example, in a developing apparatus, it is preferable to use a developing solution instead of pure water. Since a general developing solution exhibits alkalinity, in this case, PH of the rinsing liquid drainage water (A _{1 in} FIG. 3) when the upper antireflection film is completely removed.
Indicates the PH (alkaline) inherent in the developer as a rinsing liquid. After removing the upper anti-reflection film with a developing solution as a rinsing solution, a developing process is performed by discharging an amount of the developing solution necessary for still development.

(2) In the embodiment, static development is taken as an example, but the present invention can also be applied to spray development.

(3) In the embodiment, the rinsing liquid P
H was measured, but it was not necessary to measure PH,
It suffices if the hydrogen ion concentration in the effluent of the rinse can be measured. Since PH is equivalent to the hydrogen ion concentration, the end point of the removal processing of the upper layer film can be determined in a broad sense by monitoring the hydrogen ion concentration in the effluent of the rinse liquid.

(4) The hydrogen ion concentration of the effluent of the rinse liquid does not necessarily need to be measured by a PH meter. By providing an electric conductivity measuring device in place of the PH measuring device 13 in FIG. 1 and measuring the electric conductivity of the rinsing liquid effluent, the hydrogen ion concentration in the rinsing liquid effluent can also be known. And therefore, based on the measurement results,
The end point of the removal processing of the upper layer film can be determined.

(5) PH of the above-mentioned rinsing drain water
And the electrical conductivity does not necessarily need to know the absolute value, according to the amount of dissolved upper layer film contained in the effluent of the rinsing liquid,
What is necessary is just to change the measured value (relative value).

(6) The upper film to which the present invention can be applied is not limited to the upper antireflection film formed on the photoresist film, but the hydrogen ion concentration depends on the amount of dissolution contained in the rinse water. Is applicable as long as the upper layer film changes.

(7) In the embodiment, the end point of the removal processing of the upper anti-reflection film is determined based on whether or not the difference between the measurement results measured at predetermined time intervals is substantially zero. The end point of the removal processing may be determined by comparing the values with each other and determining whether or not the values match.

[0037]

As apparent from the above description, the present invention has the following effects. According to the invention described in claim 1, by measuring the hydrogen ion concentration of the effluent of the rinsing liquid, it is determined that the upper layer film has been dissolved and removed,
Since the process is shifted to the subsequent process, there is no need to perform an operation such as finding and setting a supply condition of the rinsing liquid according to the thickness of the upper layer film and the like, and the process management becomes easy. Further, since the upper layer film can be completely removed with the minimum necessary rinsing liquid, the consumption of the rinsing liquid can be suppressed, and the efficiency of the removal processing can be increased. Further, since there is no influence from a change in the thickness of the upper layer film or the like, subsequent substrate processing can be performed stably without any trouble.

According to the second aspect of the present invention, since the upper anti-reflection film on the photoresist film can be completely removed with a minimum necessary rinsing liquid, the same effect as the first aspect of the invention can be obtained. As well as stabilizing the quality of the development processing.

According to the third aspect of the invention, the upper anti-reflection film is completely removed with a minimum necessary rinsing liquid and development is performed without being affected by variations in the thickness of the upper anti-reflection film. be able to.

According to the fourth aspect of the present invention, since the pH equivalent to the hydrogen ion concentration of the effluent of the rinsing liquid is measured, it is possible to accurately determine whether or not the upper antireflection film of the substrate has been removed. Can be determined.

According to the fifth aspect of the present invention, since the electrical conductivity equivalent to the hydrogen ion concentration of the effluent of the rinsing liquid is measured, it is determined whether or not the upper antireflection film of the substrate has been removed. It can be easily determined.

According to the sixth aspect of the present invention, the quality of so-called still development, which is easily affected by the residue of the upper antireflection film, can be stabilized.

According to the seventh aspect of the present invention, the hydrogen ion concentration of the effluent of the rinse liquid is sequentially measured at predetermined time intervals, and the difference between the temporally successive measurement results becomes substantially zero. Based on this, since the supply of the rinsing liquid is switched to the supply of the developer, it is possible to easily and accurately determine whether or not the upper antireflection film has been removed.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view of a substrate to be processed.

FIG. 3 is a characteristic diagram showing a relationship between a rinsing time and a PH of a rinsing liquid flowing water.

FIG. 4 is a flowchart illustrating a processing procedure of the apparatus according to the embodiment.

[Explanation of symbols]

 5 drainage pipe 6 rinse liquid discharge nozzle 7 developer liquid discharge nozzle 10 main controller 13 PH meter W substrate

Claims (7)

[Claims] 1. A substrate processing method for performing a predetermined treatment on a substrate after dissolving and removing an upper layer film formed on a substrate with a rinsing liquid, wherein a flowing water of a rinsing liquid is supplied to the substrate on which the upper layer film is formed. A substrate processing method, comprising: determining that the upper layer film has been dissolved and removed by measuring the hydrogen ion concentration of the effluent of the rinse liquid in which the upper layer film has been dissolved; and moving to a predetermined process thereafter. . 2. The substrate processing method according to claim 1, wherein the upper film is an upper anti-reflection film formed on a photoresist film on the substrate, and the upper anti-reflection film is a rinsing liquid running water. A substrate processing method in which it is determined that the substrate has been dissolved and removed in step (1), and the process proceeds to a subsequent development process. 3. A rinsing liquid supply means for supplying rinsing liquid running water for dissolving and removing the upper anti-reflection film to a substrate on which at least a photoresist film and an upper anti-reflection film are laminated in this order; Developing solution supply means for supplying a developing solution to the substrate from which the anti-reflection film has been removed; measuring means for measuring the hydrogen ion concentration of the effluent of the rinse liquid in which the upper anti-reflection film has been dissolved; and measurement results of the measuring means Control means for switching from supply of a rinsing liquid to supply of a developing liquid based on the above. 4. The substrate processing apparatus according to claim 3, wherein the measuring unit includes a PH provided in a drainage flow path of the rinsing liquid.
A substrate processing device that is a measuring instrument. 5. The substrate processing apparatus according to claim 3, wherein the measuring unit is an electric conductivity measuring device provided in a rinse liquid drain passage. 6. The substrate processing apparatus according to claim 3, wherein said developing solution supply means supplies a developing solution on the substrate in a liquid state. 7. The substrate processing apparatus according to claim 3, wherein the control unit dissolves the upper antireflection film in a process in which the rinsing liquid supply unit supplies the substrate with flowing rinsing liquid. The hydrogen ion concentration of the effluent of the rinsing liquid is sequentially measured at predetermined time intervals, and the supply of the rinsing liquid is changed to the supply of the developing liquid based on the fact that the difference between the measurement results before and after the time becomes substantially zero. Substrate processing equipment to switch.