KR101044408B1 - Substrate treating method - Google Patents

Abstract

The present invention discloses a method for treating a substrate, comprising: a liquid which is replaced at the initial stage of substitution during chemical substrate treatment, rinsing and drying, and replacement of the chemical and rinse liquid and rinse and supercritical dry fluid. It is characterized by supplying the liquid to replace together to a process chamber.

According to this aspect, it is possible to provide a substrate processing method which can prevent the substrate from being oxidized due to atmospheric exposure of the substrate due to the disconnection of the processing fluid during the process of replacing the processing fluid.

Liquid displacement, supercritical fluids, drying

Description

Substrate Processing Method {SUBSTRATE TREATING METHOD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate processing method, and more particularly, to a substrate processing method for proceeding with chemical liquid processing and rinsing of a substrate and drying of the substrate using a supercritical fluid.

As the design rules of semiconductor devices decrease, there is a need for a deep and narrow contact forming process having a high aspect ratio and accompanying etching or cleaning processes. In the case where a wafer having a structure having such a large aspect ratio is formed, a predetermined processing step, for example, etching, cleaning, drying, or the like, is performed, when a normal wet process is used, a different film quality on the surface of the wafer is used. Defects due to damage and water spots frequently occur. In addition, in the etching process for removing a mold oxide film used as a sacrificial film when forming a storage node of a capacitor, for example, a capacitor having a relatively large thickness, the mold oxide film may be formed due to the high surface tension of pure water when the wet etching process is used. After this removal, the storage node may collapse. In an effort to solve this problem, methods for etching, cleaning or drying a predetermined film on a wafer using carbon dioxide in a supercritical state as a solvent have been proposed.

The present invention is to provide a substrate processing method capable of preventing oxidation of the substrate due to exposure of the substrate to the atmosphere.

In addition, the present invention is to provide a substrate processing method that can overcome the limitation of the process temperature rise according to the chemical liquid.

In addition, the present invention is to provide a substrate processing method capable of preventing the fall phenomenon caused by the liquid treatment liquid of a fine pattern having a large aspect ratio.

The objects of the present invention are not limited thereto, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, in the substrate processing method according to the present invention, a substrate is loaded into a processing chamber, a chemical liquid is filled into an internal space of the processing chamber, and the substrate is chemically treated, and the chemical liquid in the processing chamber is replaced with a rinse liquid. Rinse the substrate treated with the chemical liquid, and replace the rinse liquid in the processing chamber with a supercritical dry fluid to dry the rinsed substrate, and at the beginning of the substitution of the chemical liquid with the rinse liquid together with the rinse liquid And the initial stage of the substitution of the rinse liquid into the supercritical dry fluid is supplied to the process chamber together with the supercritical dry fluid.

In the substrate processing method according to the present invention having the characteristics as described above, the chemical liquid, the rinse liquid, and the supercritical drying fluid are supplied to fill the inside of the processing chamber, and the pressure is equal to or higher than normal pressure. Can be pressed.

The rinse liquid includes deionized water (DIW) and isopropyl alcohol (IPA), and the deionized water (DIW) and the isopropyl alcohol (IPA) may be sequentially supplied to the treatment chamber after the supply of the chemical liquid.

The supercritical dry fluid may be carbon dioxide in a supercritical state.

Liquid carbon dioxide may be supplied to the processing chamber between the supply of isopropyl alcohol (IPA) and the supply of carbon dioxide in the supercritical state.

The chemical liquid is SPM for removing the cured layer on the surface of the photosensitive liquid after the ion implantation process, and the SPM may be heated to a temperature of 200 ° C. or more.

The chemical liquid may be hydrogen fluoride (HF) for etching the oxide film on the substrate.

Before the chemical liquid is supplied to the treatment chamber, deionized water may be supplied to the treatment chamber to clean the treatment chamber.

The chemical liquid, the rinse liquid, and the supercritical dry fluid supplied to the process chamber may be discharged from the process chamber by applying a negative pressure to the process chamber.

By using the chemical liquid concentration meter installed at the discharge end of the treatment chamber, it is possible to detect whether the chemical liquid is replaced by the DI water.

According to the present invention, the substrate can be prevented from being oxidized by exposure to the atmosphere of the substrate due to the disconnection of the processing fluid during the process of replacing the processing fluid.

And according to the present invention, it is possible to overcome the limitation of the process temperature rise according to the chemical liquid.

Moreover, according to this invention, the fall phenomenon by the liquid process liquid of the fine pattern which has a large aspect ratio can be prevented.

Hereinafter, a substrate processing method according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible, even if shown on different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

(Example)

1 is a view showing an example of a substrate processing apparatus to which a substrate processing method according to the present invention is applied.

Referring to FIG. 1, the substrate processing apparatus includes a processing chamber 100, a processing fluid supply unit 200, and a discharge unit 300. The processing chamber 100 provides a space in which a substrate processing process is performed. The processing fluid supply unit 200 supplies the processing fluid into the processing chamber 100 loaded with the substrate, and the discharge unit 300 discharges the processing fluid used for processing the substrate from the processing chamber 100.

The process chamber 100 includes a housing 110, a substrate support member 120, and heaters 130a and 130b. The housing 110 may be provided in a thin form so that the processing fluid supplied from the processing fluid supply unit 200, which will be described later, is easily filled in a state in which the housing 110 is filled. The housing 110 has an upper housing 112 and a lower housing 114. The upper housing 112 has a cylindrical shape with an open bottom, and the lower housing 114 has a cylindrical shape with an open top. The upper housing 112 and the lower housing 114 are positioned so that the openings face each other, and are coupled to each other so that an enclosed space in which the substrate processing process is performed is formed. The substrate support member 120 may be provided on the inner bottom wall of the lower housing 114, and may be provided in the form of a plurality of support pins that support the bottom surface of the substrate. The heaters 130a and 130b are for heating the inside of the housing 110 to a predetermined process temperature, and the heater 130a of one of the heaters 130a and 130b is installed on the inner upper wall of the upper housing 112. The other heater 130b may be installed on the inner lower wall of the lower housing 114.

The inlet 115 of the processing fluid supplied by the processing fluid supply unit 200 is formed at one sidewall of the lower housing 114, and the processing fluid used to process the substrate in the processing chamber 100 is located at the other sidewall of the lower housing 114. The outlet 117 of is formed.

The processing fluid supply unit 200 supplies a liquid processing fluid to the processing chamber 100 through the first supply line 210, and supplies a dry fluid of a supercritical state to the processing chamber 100 through the second supply line 240. do.

One end of the first supply line 210 is connected to an inlet 115 formed in the lower housing 114 of the processing chamber 100, and the other end of the first supply line 210 is connected to a plurality of branch lines 212, 214, 216, 218). The liquid chemical supply source 222 is connected to the first branch line 212, and a valve 213 is provided on the first branch line 212 to open and close the flow of the chemical liquid. A liquid deionized water (DIW) source 224 is connected to the second branch line 214, and a valve 215 is provided on the second branch line 214 to open and close the flow of deionized water. A third isopropyl alcohol (IPA) source 226 is connected to the third branch line 216, and a valve 217 is provided on the third branch line 216 to open and close the flow of isopropyl alcohol. The fourth branch line 218 is connected to a liquid carbon dioxide (CO ₂ (1)) source 228, and the fourth branch line 218 is provided with a valve 219 for opening and closing the flow of liquid carbon dioxide.

The heater 232 and the pump 234 may be installed on the first supply line 210. The heater 232 may heat the liquid processing fluid supplied to the processing chamber 100 to a process temperature, and the pump 234 pressurizes the liquid processing fluid supplied to the processing chamber 100 to press the inside of the processing chamber 100. Can be maintained at process pressure.

The chemical liquid supplied from the chemical liquid source 222 may use various kinds of chemical liquids. For example, the chemical liquid may be sulfuric acid (SPM), a mixture of sulfuric acid (H ₂ SO ₄ ) and hydrogen peroxide (H ₂ O ₂ ), or hydrogen fluoride (HF) for etching an oxide film on a substrate. ) May be used.

SPM is used to remove the hardened layer on the surface of the photoresist after the ion implantation process. For efficient removal of the hardened layer, SPM is higher than the break point (180 ° C) at room temperature / atmospheric pressure It must be heated to a high temperature of 200 ° C. or higher. However, since the S.P.M evaporates before reaching the process temperature (200 ° C) in the normal temperature / atmospheric pressure, there is a limit to increasing the process temperature of the S.P.M in the normal temperature / atmospheric pressure. However, in the present invention, since the S.P.M is supplied to the process chamber 100 by being pressurized to a pressure higher than the normal pressure by the pump 234, the break point of the S.P.M at room temperature / atmospheric pressure (180) Heating may be performed at a high temperature of 200 ° C. or higher.

One end of the second supply line 240 is connected to the inlet 115 formed in the lower housing 114 of the process chamber 100, and the other end of the second supply line 240 is connected to the mixer 250. The mixer 150 receives liquid carbon dioxide, a surfactant, and a cosolvent, and mixes them under a predetermined process temperature / pressure to generate carbon dioxide (scCO ₂ ) in a supercritical state. The supercritical carbon dioxide generated in the mixer 150 is supplied to the process chamber 100 through the second supply line 240. The heater 242, the pump 244, and the valve 246 may be installed on the second supply line 240.

The liquid carbon dioxide is supplied to the mixer 250 via the liquid carbon dioxide supply line 218a branched from the fourth branch line 218, and the surfactant is supplied to the surfactant source 262 through the surfactant supply line 261-1. Co-solvent is supplied from the co-solvent source 264 through the co-solvent supply line (263-1). A valve 218a-2 is installed in the liquid carbon dioxide supply line 218a, a valve 261-2 is installed in the surfactant supply line 261-1, and a valve is provided in the cosolvent supply line 263-1. 263-2 may be installed.

The discharge unit 300 discharges the processing fluid of the liquid used in the processing chamber 100 through the first discharge line 310, and uses the second discharge line 320 in the processing chamber 100 in a supercritical state. To drain the dry fluid. The valve 312 and the pump 314 may be installed on the first discharge line 310, and the valve 322 and the pump 324 may be installed on the second discharge line 320. The pump 314 and the pump 324 may apply a negative pressure to the processing chamber 100 to forcibly discharge the processing fluid in the processing chamber 100. The densitometer 330 may be installed on the first discharge line 310. The densitometer 330 may be used to evaluate whether the chemical liquid is completely replaced with deionized water when the chemical liquid in the treatment chamber 100 is replaced with deionized water, which will be described later.

Hereinafter, the process of processing a board | substrate using the substrate processing apparatus which has the above structures is demonstrated. The substrate processing step is, for example, a step of removing the cured layer on the surface of the photosensitive liquid after the ion implantation step by using S.P.M (SPM), or a step of etching an oxide film on the substrate using hydrogen fluoride (HF). And the like.

FIG. 2 is a process flowchart of a substrate processing method according to the present invention, and FIG. 3 is a view showing a substitution pattern of processing fluids according to the process of FIG. 2.

Referring to FIGS. 1, 2, and 3, first, the deionized water source 224 may supply deionized water into the process chamber 100 to clean the interior of the process chamber 100 (S10).

Subsequently, the substrate is loaded into the processing chamber 100, and the chemical liquid supply source 222 supplies the chemical liquid to the processing chamber 100. The chemical liquid is supplied to the process chamber 100 while being pressurized by the pump 234, and the chemical liquid supplied may be heated to a process temperature by the heater 232. The chemical liquid may be completely filled to fill the internal space of the processing chamber 100, and the chemical liquid may be supplied through the inlet 115 and discharged through the outlet 117 during the process. The chemical liquid is continuously supplied for a predetermined process time t ₁ , and the substrate is processed according to the type of process (S20).

When the chemical liquid processing of the substrate is completed, the chemical liquid in the processing chamber 100 is replaced with deionized water. The deionized water may be supplied from the deionized water source 224 to the treatment chamber 100, and the chemical liquid and the deionized water may be supplied together to the treatment chamber 100 for a predetermined time Δt at the time of substitution of the chemical liquid into the deionized water. This is to prevent the substrate in the processing chamber 100 from being exposed to the air and oxidized. Deionized water is continuously supplied for a sufficient time t ₂ so that the chemical liquid in the treatment chamber can be completely replaced with deionized water and discharged through the outlet 117. Substitution of the chemical liquid by deionized water may be performed by using the chemical liquid concentration meter 330 installed on the first discharge line 310. (S30)

When the replacement of the chemical liquid with deionized water is completed, the deionized water in the treatment chamber 100 is replaced with isopropyl alcohol (IPA). Isopropyl alcohol is supplied from the isopropyl alcohol source 226 to the treatment chamber 100, and deionized water and isopropyl alcohol together with the deionized water for a predetermined time (Δt) at the beginning of the substitution of deionized water to isopropyl alcohol. Can be supplied. This is to prevent the substrate in the processing chamber 100 from being exposed to the air and oxidized. Isopropyl alcohol is continuously supplied for a predetermined process time t ₃ and discharged through the outlet 117.

When the deionized water is replaced with isopropyl alcohol, isopropyl alcohol in the treatment chamber 100 is replaced with liquid carbon dioxide. Liquid carbon dioxide is supplied to the processing chamber 100 from the liquid carbon dioxide source 226, and isopropyl alcohol and liquid carbon dioxide are supplied together to the processing chamber 100 for a predetermined time (Δt) at the initial stage of the substitution of the isopropyl alcohol to the liquid carbon dioxide. Can be. This is to prevent the substrate in the processing chamber 100 from being exposed to the air and oxidized. The liquid carbon dioxide is continuously supplied for a predetermined process time t ₄ and discharged through the outlet 117.

As such, the reason why the liquid carbon dioxide is supplied before the drying process using the carbon dioxide in the supercritical fluid state is that isopropyl alcohol may be dissolved by the supercritical carbon dioxide, but the reaction rate is slow.

When the isopropyl alcohol is replaced by the liquid carbon dioxide, the liquid carbon dioxide in the processing chamber 100 is replaced with carbon dioxide in a supercritical state. The supercritical carbon dioxide is supplied from the mixer 250 to the processing chamber 100, and the liquid carbon dioxide and the supercritical carbon dioxide are supplied together to the processing chamber 100 for a predetermined time Δt at the initial stage of the substitution of the liquid carbon dioxide into the supercritical carbon dioxide. Can be. This is to prevent the substrate in the processing chamber 100 from being exposed to the air and oxidized. Supercritical carbon dioxide is continuously supplied for a predetermined process time, and discharged through the outlet 117. (S60)

Through the processes S10 to S60 as described above, the substrate may be chemically treated, the chemically treated substrate may be rinsed, and the rinsed substrate may be dried. In particular, when a hydrophobic chemical solution such as hydrogen fluoride (HF) is used as the chemical liquid, a pattern with a large aspect ratio may fall due to the surface tension of the chemical liquid, but the substitution process of the chemical liquid and drying using a supercritical fluid as described above. This can be prevented through the process.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

The drawings described below are for illustrative purposes only and are not intended to limit the scope of the invention.

1 is a view showing an example of a substrate processing apparatus to which a substrate processing method according to the present invention is applied.

2 is a process flow diagram of a substrate processing method according to the present invention.

FIG. 3 is a view illustrating a substitution pattern of process fluids according to the process of FIG. 2.

<Description of Symbols for Main Parts of Drawings>

100: processing chamber 100 200: processing fluid supply

300: discharge part

Claims (10)

Load the substrate into the process chamber, Supplying a chemical liquid to an inner space of the processing chamber; Supplying deionized water (DIW) into said processing chamber; Supplying isopropyl alcohol (IPA) into the process chamber; Supplying a supercritical dry fluid into the process chamber; And supplying liquid idealized carbon into the processing chamber between the step of supplying isopropyl alcohol (IPA) and the step of supplying a supercritical dry fluid. The method of claim 1, The chemical liquid, the deionized water (DIW), the isopropyl alcohol (IPA), and the supercritical drying fluid are supplied to fill the inside of the processing chamber, and are pressurized to a pressure above normal pressure. Substrate processing method. The method of claim 2, And said supercritical dry fluid is carbon dioxide in a supercritical state. The method of claim 1, And at the initial stage of supplying the deionized water (DIW), the chemical liquid is supplied to the process chamber together with the deionized water (DIW). The method of claim 1, In the initial supply of the isopropyl alcohol (IPA) substrate processing method characterized in that for supplying the deionized water (DIW) with the isopropyl alcohol (IPA) to the processing chamber. The method of claim 4, wherein The chemical liquid is SPM for removing the cured layer on the surface of the photosensitive liquid after the ion implantation process, The S.P.M (SPM) is a substrate processing method, characterized in that heated to a temperature of 200 ℃ or more. The method of claim 4, wherein And said chemical liquid is hydrogen fluoride (HF) for etching an oxide film on said substrate. The method according to claim 2 or 5, And deionized water is supplied to the processing chamber before the chemical liquid is supplied to the processing chamber to clean the inside of the processing chamber. The method of claim 2, And applying a negative pressure to the processing chamber to discharge the chemical liquid, the deionized water (DIW), the isopropyl alcohol (IPA), and the supercritical dry fluid from the processing chamber. The method of claim 1, And detecting the substitution of the chemical liquid by the DI water using a chemical liquid concentration meter provided at the discharge end of the processing chamber.

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