JP2010080668A - Method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor device capable of restraining a collapse of a pattern formed on the surface of a substrate, and capable of preventing an adhesion of a contaminated material derived from an organic solvent of IPA (isopropyl alcohol) or the like on the surface of the substrate. <P>SOLUTION: The method of manufacturing the semiconductor device has a cleaning step for cleaning the surface of the substrate while rotating the substrate. The cleaning step includes the steps of: cleaning the surface of the substrate by supplying the cleaning liquid to the substrate; rinsing the surface of the substrate after cleaning by supplying the rinse water to the substrate; and drying the substrate after being rinsed. In the step of rinsing the surface of the substrate, an organic-solvent-mixed rinse water with the organic solvent mixed to the rinse water is used, and the organic solvent distilled or filtered is mixed to the rinse water. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor device including a step of cleaning a substrate surface such as a semiconductor wafer.

The film formation pattern conditions of the semiconductor substrate are in the direction of miniaturization, and along with this, various methods are employed to cope with the miniaturization of the cleaning technique.
However, it is known that the pattern collapse is caused by the surface tension of water used at the time of drying after rinsing in the single wafer cleaning apparatus. For this, there is a method using IPA (isopropyl alcohol) or the like, but secondary contamination is caused by impurities contained in the organic solvent itself such as IPA.

  Further, when cleaning a semiconductor substrate, one or more kinds of acids or alkalis (for example, hydrofluoric acid, hydrochloric acid, sulfuric acid, ammonia water, hydrogen peroxide water) are mixed and diluted with DIW (deionized water) ( SC1 solution: ammonia water and hydrogen peroxide solution mixed with DIW and diluted with DIW, SC2 solution: hydrochloric acid and hydrogen peroxide solution mixed with DIW, etc.) are used. After cleaning the substrate by these, rinsing is performed using DIW or carbonated water in which carbon dioxide is dissolved in DIW, and then the substrate is taken out through a drying process.

  However, DIW or carbonated water used in the rinsing process has a strong surface tension (for example, the surface tension of water is 72.75 mN / m), and the pattern formed on the substrate collapses due to this force. Further, if DIW or the like is dried as it is, drying marks called watermarks are likely to remain. As a means for solving these problems, a method of introducing IPA into DIW is conceivable (for example, the surface tension of 10% IPA is 39.4 mN / m), but the cleaning substrate is secondarily contaminated by impurities contained in IPA itself.

  An object of the present invention is to provide a method for manufacturing a semiconductor device that can solve the above problems and prevent adhesion of contaminants derived from an organic solvent such as IPA to the substrate surface.

  According to one aspect of the present invention, in the method of manufacturing a semiconductor device having a cleaning process of cleaning the substrate surface while rotating the substrate, the cleaning process supplies the cleaning liquid to the substrate to clean the substrate surface. Rinsing the substrate surface, and a step of rinsing the substrate surface after the cleaning by supplying rinsing water to the substrate, and a step of drying the substrate after the rinsing In the process, there is provided a method of manufacturing a semiconductor device in which an organic solvent mixed rinse water obtained by mixing an organic solvent with the rinse water is used, and the organic solvent is mixed with the rinse water after being distilled or filtered. .

  According to the present invention, it is possible to suppress the collapse of the pattern formed on the substrate surface and to prevent the contaminants derived from the organic solvent such as IPA from adhering to the substrate surface.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a substrate cleaning apparatus 10 according to an embodiment of the present invention.
The substrate cleaning apparatus 10 has a cleaning apparatus main body 12, and a cleaning chamber 14 is configured by being surrounded by the substrate cleaning apparatus main body 12. In the cleaning chamber 14, a support 18 that horizontally supports a substrate 16 such as a semiconductor wafer is disposed. The support 18 is connected to a rotation mechanism 20 made of a motor or the like via a rotation shaft 21, and the substrate 16 that is horizontally supported is rotated by the rotation mechanism 20.

  The periphery of the support 18 is surrounded by a cover 22. As will be described later, the cover 22 is configured to receive a chemical liquid flying from the substrate 16 when the substrate 16 is rotated by the support 18.

  As shown in FIG. 2, a substrate loading / unloading port 24 is formed on the side surface of the cleaning apparatus main body 12. A gate valve 26 is provided at the substrate loading / unloading port 24, and the substrate loading / unloading port 24 is opened and closed by the gate valve 26. Further, a substrate transfer machine 27 for transferring the substrate 16 to the support 18 through the substrate carry-in / out port 24 is provided.

  A first nozzle 28 and a second nozzle 30 are inserted into the cleaning chamber 14 described above. The first nozzle 28 and the second nozzle 30 are horizontally arranged such that their respective tips extend to near the center of the substrate 16 supported by the support 18. The first nozzle 28 is connected to a cleaning liquid supply unit 32 that supplies a cleaning liquid made of DHF, for example, via a control valve 32 a that controls the supply of the cleaning liquid, and the cleaning liquid is supplied from the first nozzle 28 to the substrate 16. Supplied to the center of the. The second nozzle 30 is a control valve that controls the supply of rinse water and IPA to a rinse water supply unit 34 that supplies rinse water made of pure water, for example, and an IPA supply unit 36 that supplies, for example, IPA that is an organic solvent. The second nozzle 30 supplies rinsing water mixed with IPA to the center of the substrate 16.

  The water supply unit 40 opens around the inner upper portion of the cover 22 described above, and the other end is connected to a pure water supply unit 42 that supplies water made of pure water so that water can be supplied to the inner surface of the cover 22. It has become. The water supply unit 40 is provided with a control valve 42a that controls the supply of pure water. The pure water supply unit 42 may be shared with the rinse supply unit 34.

  A drain pipe 44 for discharging pure water supplied to the cover 22 is connected to the lower surface of the cover 22, and the drain pipe 44 extends to the outside of the substrate cleaning apparatus body 12. Then, the pure water in the cover 22 is discharged. Note that the cleaning liquid and the rinsing water supplied to the substrate 16 are also discharged through the drain pipe 44.

A drying gas supply pipe 46 is connected to the upper portion of the substrate cleaning apparatus main body 12. A drying gas supply unit 48 is connected to the other end of the drying gas supply pipe 46. The drying gas supply pipe 46 is provided with a control valve 48a for controlling the supply of the drying gas. For example, nitrogen (N ₂ ) is used as the drying gas. Further, an exhaust pipe 50 for discharging the drying gas is connected to the lower part of the substrate cleaning apparatus main body 12.

The controller 52 includes a computer, and is controlled by the rotation of the support 18 by the rotation mechanism 20, opening / closing of the substrate loading / unloading port 24 by the gate valve 26, loading / unloading of the substrate 16 by the substrate transfer machine 27, and the control valve 32a. Supply of chemical solution by the first nozzle 28, supply of IPA mixed rinse water by the second nozzle 30 controlled by the control valve 38, supply of pure water from the water supply unit 40 controlled by the control valve 42a, control valve 48a The supply of nitrogen (N ₂ ) from the drying gas supply pipe 46 controlled by the above is controlled.

  Next, a method for cleaning a substrate will be described as one step of a semiconductor device (device) manufacturing process using the substrate cleaning apparatus 10 having the above-described configuration.

FIG. 3 is a flowchart showing a control flow by the controller 52.
First, in step S10, the substrate loading / unloading opening 24 is opened by the gate valve 26, and the substrate 16 on which the pattern is formed is loaded into the cleaning chamber 14 by the substrate transfer device 27.

  In the next step S 12, the substrate transfer machine 27 is further controlled to support (set) the substrate 16 on the support 18, and the substrate loading / unloading port 24 is closed by the gate valve 26.

  In the next step S <b> 14, the rotation of the substrate 16 is started by rotating the support 18 through the rotation shaft 21 by the rotation mechanism 20.

  In the next step S16, as shown in FIG. 4, while the rotation of the substrate 16 is maintained, the chemical solution is supplied from the first nozzle 28 toward the center of the substrate 16 to clean the surface of the substrate 16. The chemical solution used here is DHF, SC1 solution, SC2 solution, or the like.

  In the next step S18, first, IPA is supplied from the IPA supply unit 36 in order to mix IPA with the rinse water used in step S18 (step S104). Then, as shown in FIG. 5, while maintaining the rotation of the substrate 16, the supply of the chemical solution from the first nozzle 28 is stopped, the control valve 38 is opened, and the rinse in which IPA is mixed from the second nozzle 30. Water is supplied toward the center of the substrate 16 to wash away the chemical remaining on the substrate surface. The rinse water used here is DIW or carbonated water.

In the next step S20, as shown in FIG. 6, while maintaining the rotation of the substrate 16, the supply of the rinse water mixed with the IPA from the second nozzle 30 is stopped, and the rinse water on the substrate is removed. Sift out by centrifugal force due to rotation. In this step S20, the cleaning chamber 14 is exhausted from the exhaust pipe 50 while supplying N ₂ as a drying gas from the drying gas supply section 48 through the drying gas supply pipe 46 to the cleaning chamber 14. An N ₂ atmosphere is used, and the substrate 16 is dried in the N ₂ atmosphere.
In addition, in order to improve safety | security, the supply of the pure water from the water supply part 40 to the inner surface of the cover 22 is good to carry out continuously from the chemical | medical solution washing | cleaning process of step S16 to the drying process of this step S20. That is, it is preferable to supply pure water to the inner surface of the cover 22 at least while the chemical solution, the rinse water, etc. fly from the substrate 16 to the cover 22.

  In the next step S22, the rotation of the substrate 16 is stopped by stopping the rotation of the support 18 by the rotation mechanism 20.

  According to the next step S 24, the substrate loading / unloading port 24 is opened by the gate valve 26, and the substrate 16 is unloaded from the cleaning chamber 14 by the substrate transfer machine 27. Thereafter, the film is transferred to another apparatus, for example, an epitaxial growth apparatus, and processing such as film formation is performed.

According to the present invention, the IPA supply unit 36 is connected to an IPA distillation / filtration unit 37 that distills or filters IPA as shown in FIG. Then, the replenished IPA is distilled or filtered in the IPA distillation / filtration unit 37, and the distilled or filtered IPA is supplied from the IPA supply unit 36 into the cleaning chamber 14.
The IPA storage unit 39 is an IPA storage unit used in a second supply method to be described later, and is not necessarily provided when supplying IPA by the first supply method to be described later.
That is, in the first supply method described later, the IPA storage unit 39 can be omitted, and the IPA supply system can be further simplified.

7A and 7B show the IPA supply flow in the IPA distillation / filtration unit 37 and the IPA supply unit 36. FIG.
These controls are performed by the controller 52.
FIG. 7A shows a first method for supplying distilled / filtered IPA.
In FIG. 7A, distillation or filtration is performed in accordance with the IPA usage request from the cleaning apparatus main body 12. For this, a filtration method is preferably used.
First, in step S100, IPA is replenished based on a replenishment command.

  Next, in step S <b> 102, the replenished IPA is distilled or filtered in the IPA distillation / filtration unit 37.

  Next, in step S104, the distilled or filtered IPA is supplied from the IPA supply unit 36 into the cleaning chamber 14.

FIG. 7B shows a second method for supplying distilled / filtered IPA.
FIG. 7B differs from the first supply method in that, in addition to the IPA distillation / filtration unit 37, an IPA storage unit 39 that stores the distilled or filtered IPA is provided.
The IPA storage unit 39 is configured as a container for storing distilled or filtered IPA, and is provided between the IPA supply unit 36 and the IPA distillation / filtration unit 37.
In the second supply method, IPA is distilled or filtered in the IPA distillation / filtration unit 37 to prepare high-purity IPA, and a certain amount of this high-purity IPA is stored in a container of the IPA storage unit 39 for washing. The IPA distillation / filtration unit 37 performs IPA distillation or filtration when the amount reduced by the use in the device is reduced each time or over a certain amount, and the high purity IPA obtained by distillation or filtration is used in the washing device The container of the IPA storage unit 39 is replenished by the amount reduced by.
First, in step S100, IPA is replenished based on a replenishment command.

  Next, in step S <b> 102, the replenished IPA is distilled or filtered in the IPA distillation / filtration unit 37.

  Next, in step S103, the distilled or filtered IPA is stored in the IPA storage unit 39.

  Next, in step S <b> 104, the IPA stored in the IPA storage unit 39 is supplied from the IPA supply unit 36 into the cleaning chamber 14.

  In this case, since the time during which distillation or filtration is not performed, such as immediately after completion of the distillation / filtration process, can be easily grasped to some extent, it is easy to automatically perform distillation residue processing, filter medium regeneration processing, etc. Get smaller.

As described above, distillation is a method in which a certain amount is stored in a container in advance as in the second supply method, and the required amount is compensated every time it is reduced by rinsing or the like, or in accordance with use as in the first supply method. The distillation is carried out in one of the ways in each case.
Examples of the distillation method include vacuum distillation and air distillation. Impurities removed by distillation include high-boiling organic substances and elution from distillation apparatus components other than those derived from containing an organic solvent such as IPA. Therefore, it is desirable to carry out distillation at a lower temperature. Distillation is preferably performed at a temperature lower than the boiling point of an organic solvent such as IPA. In the case of IPA, the boiling point is 82.4 ° C., and therefore, for example, 80 ° C. or less, preferably 70 ° C. or less, more preferably 60 ° C. This should be done as follows.

Here, in order to confirm the effect of distillation, the result of measuring the amount of high-boiling substances in IPA before and after distillation will be described.
The distillation of IPA was performed at 70 ° C., and the amount of high-boiling substances in IPA was measured before and after the distillation.
As a result, the total amount of high-boiling substances in IPA before distillation was 10.60 ng / L, and in particular, the amount of DOP (dioctyl phthalate) was 0.130 ng / L, whereas IPA after distillation The amount of high-boiling substances therein was 0.105 ng / L in total, and the amount of DOP was 0.022 ng / L. That is, the total removal rate of high-boiling substances in IPA by distillation was 99%, and the removal rate of DOP was 83%.
From these facts, it can be seen that by distilling IPA, it is possible to obtain high-purity IPA in which the amount of high-boiling substances is 0.105 ng / L or less and DOP is 0.022 ng / L or less.

  In addition to the distillation method, impurity removal using a filtering agent such as a filtration membrane, an adsorption tube or an adsorbent can be mentioned. In this case, it must be used in consideration of the useful life of the filtering agent. For example, a cleaning solution for regeneration of the filtering agent is flowed every time a certain amount of filtering processing is performed, or the temperature of the filtering agent is increased. It must be used with a treatment to remove impurities accumulated in the filtering agent. Examples of the adsorbent include a chromatography carrier.

Next, a second embodiment of the present invention will be described.
FIG. 8 is a flowchart showing a control flow in the second embodiment of the present invention.
In the second embodiment of the present invention, in the substrate cleaning apparatus 10 of the first embodiment, either the rinse water or the IPA is supplied from the second nozzle 30 to the center of the substrate 16. .
Here, steps S10 to S16 and steps S20 to S24 are the same as the control flow in the first embodiment.

  After the chemical solution cleaning in step S16, in step S18, the supply of the chemical solution from the first nozzle 28 is stopped while maintaining the rotation of the substrate 16, and the pure water as the rinse water is supplied from the second nozzle 30 to the substrate 16. Supply toward the center and wash away the chemical remaining on the substrate surface.

Then, in the next step S19, a step of replacing the rinse water with IPA is added.
Here, in step S <b> 19, the supply of pure water as the rinse water is stopped while maintaining the rotation of the substrate 16, and IPA as the replacement liquid is supplied from the second nozzle 30 toward the center of the substrate 16. The pure water on the substrate is replaced with IPA. At this time, the IPA to be supplied uses IPA distilled or filtered by the first supply method or the second supply method described above (step S104).
In step S <b> 19, pure water is supplied from the water supply unit 40 to the inner surface of the cover 22. This can reduce the risk of combustion caused by IPA blown to the inner surface of the cover 22. The pure water supplied to the inner surface of the cover 22 is discharged to the outside through the drain pipe 44.
Note that the supply of pure water to the inner surface of the cover 22 needs to be performed at least in steps S19 and S20 where the IPA flies to the inner surface of the cover 22, but as in the above-described embodiment, the supply of continuous water is continuously performed from step S16 to step S20. You may make it carry out.

  Then, the substrate drying in the next step S20, the substrate rotation stop in step S22, and the substrate unloading step in step S24 are performed.

  According to the present invention, by using an organic solvent such as IPA that has been distilled or filtered during or after rinsing in the substrate cleaning step, it is highly clean even without using IPA or the like whose contamination level is controlled to a high level. A clean surface is obtained. Moreover, since distillation or filtration is performed at the point of use, it can also be effective for contamination caused by transportation and storage of IPA and the like.

Hereinafter, preferred embodiments of the present invention will be additionally described.
According to one aspect of the present invention, in the method of manufacturing a semiconductor device having a cleaning process of cleaning the substrate surface while rotating the substrate, the cleaning process supplies the cleaning liquid to the substrate to clean the substrate surface. Rinsing the substrate surface, and a step of rinsing the substrate surface after the cleaning by supplying rinsing water to the substrate, and a step of drying the substrate after the rinsing In the process, there is provided a method of manufacturing a semiconductor device in which an organic solvent mixed rinse water obtained by mixing an organic solvent with the rinse water is used, and the organic solvent is mixed with the rinse water after being distilled or filtered. .

  According to another aspect of the present invention, in the method of manufacturing a semiconductor device having a cleaning process of cleaning the substrate surface while rotating the substrate, the cleaning process supplies the cleaning liquid to the substrate to clean the substrate surface. Rinsing the substrate surface, and a step of rinsing the substrate surface after the cleaning by supplying rinsing water to the substrate and drying the substrate after the rinsing The first rinsing water containing pure water is supplied to the substrate, the second rinsing water containing an organic solvent is supplied to the substrate, and the first rinsing on the substrate surface is performed. Replacing the water with the second rinsing water, and providing the second rinsing water provides a method for manufacturing a semiconductor device used after the organic solvent is distilled or filtered. .

Preferably, an organic solvent such as IPA used after cleaning the substrate is distilled.
Preferably, the distillation is performed in a distillation section provided as a part of the cleaning device.
Preferably, the distillation is performed each time it is used.
Preferably, the distillation is performed in advance and stored in a container.
Preferably, the organic solvent such as IPA used after cleaning the substrate is filtered to remove impurities.
Preferably, the filtering agent used in the filtration is a filtration membrane or an adsorbent.
Preferably, the filtration is performed at each use.
Preferably, the filtration is performed in advance and stored in a container.

It is sectional drawing which shows the inside of the apparatus of the board | substrate cleaning apparatus which concerns on embodiment of this invention. It is a side view showing a substrate cleaning device and a substrate transfer machine concerning an embodiment of the present invention. It is a flowchart which shows the control flow by the controller in embodiment of this invention. It is the top view and side view which show the state of the board | substrate cleaning apparatus of the chemical | medical solution cleaning process in embodiment of this invention. It is the top view and side view which show the state of the board | substrate cleaning apparatus of the rinse process in embodiment of this invention. It is the top view and side view which show the state of the board | substrate cleaning apparatus of the drying process in embodiment of this invention. (A) First supply method of IPA after distillation / filtering in the embodiment of the present invention (b) Second supply method of IPA after distillation / filtration. It is a flowchart which shows the control flow by the controller in the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Substrate cleaning apparatus 12 Substrate cleaning apparatus main body 14 Cleaning chamber 16 Substrate 18 Support tool 20 Rotating mechanism 28 First nozzle 30 Second nozzle 32 Cleaning liquid supply part 34 Rinse water supply part 36 IPA supply part 52 Controller

Claims (1)

In a manufacturing method of a semiconductor device having a cleaning step of cleaning a substrate surface while rotating the substrate,
The washing step includes
Supplying a cleaning liquid to the substrate to clean the substrate surface;
Rinsing the substrate surface after the cleaning by supplying rinsing water to the substrate;
Drying the substrate after the rinsing,
In the step of rinsing the substrate surface, an organic solvent mixed rinse water obtained by mixing an organic solvent with the rinse water is used, and the organic solvent is mixed with the rinse water after being distilled or filtered. A method for manufacturing a semiconductor device.

Images