JP2006332215A - Method of processing microstructure and apparatus thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To evenly perform with good reproduction in a short time all processes from etching where an article to be processed is placed on the same sample holder and a fine structure is formed on the surface with an etchant to drying by supercritical fluid. <P>SOLUTION: The method of processing the microstructure is configured such that, after etching of forming a microstructure by performing etching to the article placed on a sample holder by an etchant, the etchant is substituted for pure water, and then, after the pure water is substituted for an organic solvent, the article is taken out from a substitution processor and the organic solvent is removed from the article by the supercritical fluid and is subjected to supercritical drying. In the method, the article undergoes all processings from the etching to the supercritical drying while being placed on the sample holder. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a novel fine structure processing method and apparatus for forming a fine structure on the surface of an object to be processed by performing an etching process and then performing a rinsing cleaning and a drying process using a supercritical fluid.

  Conventionally, in order to manufacture a large-scale, high-density, high-performance device, a resist formed on a silicon wafer is exposed, developed, rinsed and dried to form a pattern, and then coated, etched, and rinsed. It is manufactured through a process such as drying. In particular, the resist is a polymer material that is sensitive to light, X-rays, electron beams, etc., and in each process, a chemical solution such as a developer or a rinse solution is used in the development and rinse cleaning process, so the rinse cleaning process After that, a drying process is essential. Patent Document 1 discloses that etching, development, rinsing, and drying with a supercritical fluid are performed in the same tank.

  In this drying process, when the space width between the resist patterns formed on the substrate is about 100 nm or less, the surface tension of the chemical solution remaining between the patterns causes Laplace force (capillary force) to act between the patterns and the pattern collapses. The problem that occurs occurs.

  On the other hand, for example, manufacturing a MEMS (Micro Electromechanical System) part of a three-dimensional microstructure part having a movable part such as an acceleration sensor or an actuator includes a step of forming a microstructure including a movable part with an etching solution such as hydrofluoric acid, It includes a step of cleaning and removing the etching solution with pure water and a drying step. Also in this drying process, the surface tension due to the chemical solution remaining between the fine structures acts like the resist pattern, and the phenomenon that the movable part sticks to the substrate occurs. Patent Documents 2 to 4 show a drying process for reducing the surface tension acting between fine structures in order to prevent pattern collapse and sticking due to the action of the surface tension of the chemical solution remaining between the fine structures. Yes.

This conventional drying method using a supercritical fluid such as carbon dioxide has the following basic steps.
(1) A step in which a remaining liquid such as water in a sample that is not soluble in a liquid or a fluid in a supercritical state is previously replaced with an organic solvent that is soluble in the fluid, such as ethanol or 2-propanol.
(2) A step of horizontally transporting and setting in a high-pressure container serving as a drying chamber in a state dipped or wetted in the rinse liquid, specifically, a condition in which the rinse liquid is placed on the substrate.
(3) A step of sealing the high-pressure vessel.
(4) A step of introducing a fluid in a liquid state or a supercritical state into a high-pressure vessel and increasing the pressure to a predetermined pressure.
(5) A step of replacing the liquid or supercritical fluid introduced into the high-pressure vessel with the rinse liquid.
(6) A step of increasing the pressure and raising the temperature of the high-pressure vessel to a critical point or more after replacing the liquid fluid and the rinsing liquid when a liquid fluid is introduced into the high-pressure vessel.
(7) A step of discharging the supercritical fluid from the high-pressure vessel.
(8) A step of taking out the substrate from the high-pressure vessel.

JP-A-11-87306 JP 2003-109933 A JP-A-9-139374 JP-A-5-315241

  Performing the drying process from the etching process in Patent Document 1 in the same tank requires a long time for cleaning the processing liquid in each process, so that the processing time becomes long in all processes.

  13 and 14 are cross-sectional views showing a state in which the pure water replacement process after the etching process and the etching process is performed. As shown in FIG. 13, the object to be treated 2 rinsed with pure water 1 is rinsed with isopropyl alcohol (IPA), and the object to be treated is placed on the tray 3 containing IPA 4. 2 and IPA rinse replacement processing is performed for a certain period of time. Thereafter, as shown in FIG. 14, the object 2 on which the pure water high-concentration liquid 5 replaced with IPA 4 is taken out from the tray 3 and placed in the tray 3 containing the new IPA 4 to reduce the pure water concentration. The IPA rinse replacement process is performed again for a predetermined time. Such replacement processing is repeated a plurality of times.

  Finally, as shown in FIG. 15, the workpiece 2 on which the pure water concentration solution 6 replaced with IPA 4 is placed is taken out and mounted on another sample holder 7 shown in this embodiment in which IPA 4 is placed. At this time, the workpiece 2 is held by the sample presser 9 and the presser plate 8 pressed by the pressing spring 10 in the sample holder 7, and the pure water concentration is further lowered. After performing the above-described replacement process, the workpiece 2 is placed in the high-pressure processing container in the supercritical drying process, and the drying process is performed.

  However, the step of removing the workpiece 2 from the wet etching treatment liquid or the remaining liquid such as pure water in the workpiece 2 that is not soluble in the liquid or the fluid in a supercritical state is an organic solvent that is soluble in advance, For example, in the process of substituting with ethanol, 2-propanol, etc., because different processing containers and sample holders were used, the objects to be processed were sequentially removed from the wet etching processing tank via the atmosphere. A substitution treatment with an organic solvent was carried out, and the fine structure contacted the atmosphere, and pattern collapse and sticking occurred due to the effect of surface tension outside the control, and a drying treatment with good reproducibility could not be performed.

  The object of the present invention is to place all the processes from the etching process, which is placed on the same sample holder and forming a fine structure on the surface with the etching liquid, to the drying with the supercritical fluid, in a short time and with good reproducibility. It is an object of the present invention to provide a fine structure processing method and an apparatus thereof.

  In the present invention, after an etching process for forming a fine structure by performing an etching process using an etching solution on an object placed on a sample holder, the etching solution is replaced with pure water, and then the pure water is replaced with an organic solvent. In the fine structure processing method for supercritical drying, in which the object to be processed is taken out from the replacement processing unit and the organic solvent is removed from the object to be processed by a supercritical fluid, the entire process from the etching process to the supercritical drying is performed. On the other hand, the present invention resides in a fine structure processing method characterized in that the object to be processed is placed on the sample holder.

  According to the present invention, the entire process from the etching process, which is placed on the same sample holder and forms a fine structure on the surface with an etching solution, and is dried with a supercritical fluid is performed uniformly in a short time with good reproducibility. It is an object of the present invention to provide a fine structure processing method and an apparatus thereof.

  The present invention replaces the etching solution with pure water from the etching step with an etching solution that forms a fine structure on an object to be processed such as glass, silicon and metal, and replaces the pure water with an organic solvent. The present invention resides in a fine structure processing method and apparatus for processing all processes up to a supercritical drying process for drying with a supercritical fluid using the same sample holder. Specifically, the whole process has the following procedures.

  Place the object to be processed when forming the fine structure in the sample holder, place it in the internal processing container of the liquid processing container, supply the target etching solution such as hydrofluoric acid to the internal processing container, and immerse it for the target time A fine structure is formed on the surface of the workpiece. Thereafter, the etching solution is discharged, pure water is introduced, pure water rinsing is performed while replacing the etching solution remaining in the sample holder portion with pure water, and pure water is discharged after a certain time. Next, an organic solvent soluble in a fluid used in the drying process, such as ethanol or 2-propanol, is introduced into the pure water remaining in the sample holder portion, and the pure water remaining in the sample holder portion is replaced with an organic solvent.

  In addition, in order to stabilize the replacement time of the wet etching treatment liquid and pure water / organic solvent, in order to keep the temperature of those liquids constant, a temperature-controlled solvent is circulated between the liquid treatment container and the external container. In addition, a plurality of supply ports of pure water and organic solvent are provided obliquely, and the sample holder and the organic solvent come into contact with the sample holder and the sample in the liquid processing container while rotating, so that the sample holder and Improves replacement efficiency with liquid in the vicinity of the object to be processed.

  Furthermore, the projection provided between the sample holder and the discharge port causes pure water or an organic solvent to flow downward with respect to the center lower part of the liquid processing container, and further enters the upper part of the object to be processed. The replacement efficiency with the liquid in the vicinity of the object can be improved. Furthermore, it is also effective to give vibrations in the X direction, Y direction, and Z direction to the liquid processing container itself.

  More specifically, in the gap such as the outer peripheral portion of the sample holder to be processed, in particular, an etching solution or pure water remains or stagnate, and a groove is provided in the sample holder so that the sample holder is efficiently replaced. By controlling the pressure and flow rate of the supplied pure water and organic solvent, the replacement process is performed by changing the speed and direction of the rotating flow and the downward flow.

  The sample holder that has been replaced with the organic solvent is placed on the holding means in the high-pressure vessel by the transport mechanism, and the fluid that becomes a gas at normal temperature and normal pressure and a liquid at high pressure in the high-pressure vessel is liquid or supercritical. Introduce up to the set pressure in the state and change the specific gravity of the fluid by changing at least one of the temperature and pressure of the fluid before discharging the rinse liquid, and the specific gravity difference between the rinse liquid and the fluid in the high pressure vessel due to the change in specific gravity And the rinsing liquid on the substrate as the object to be processed is collected on the upper side or the lower side in the inclined high pressure vessel.

  The collected rinse liquid is discharged from at least one discharge port provided on the upper side or the lower side in the inclined high-pressure vessel, and further remains in the vicinity of the substrate outer periphery or the circumferential contact portion between the sample holder and the substrate. In order to efficiently separate the rinsing liquid remaining between the rinsing liquid, the sample holder, and the substrate, the remaining rinsing liquid is efficiently separated through a groove provided in the sample holder. Thereafter, the temperature of the fluid is raised to a critical temperature or higher while maintaining the fluid at a critical pressure or higher, and the workpiece is dried by discharging the fluid while maintaining the fluid temperature at or higher than the critical temperature.

  The above procedure is summarized as follows. Place the sample for forming the fine structure in the sample holder, place it in the internal processing container of the liquid processing container, supply the target etching solution such as hydrofluoric acid to the internal processing container, and immerse it for the target time A fine structure is formed. Thereafter, the etching solution is discharged, pure water is introduced, pure water rinsing is performed while replacing the etching solution remaining in the sample holder portion with pure water, and pure water is discharged after a certain time. Next, an organic solvent is introduced, and the pure water remaining in the sample holder portion is replaced with the organic solvent. The temperature of the internal processing container is kept constant by the temperature-controlled solvent supplied to and from the external processing container, and the sample holder and the pure water / organic solvent are supplied at a certain angle with the supplied etching solution and pure water / organic solvent. Replacement process near the sample, replacement process using the X, Y, and Z vibration mechanisms provided at the bottom of the liquid processing vessel, and high-pressure processing that can be performed efficiently by the groove provided in the sample holder, and further performs a supercritical drying process The same sample holder is used to process the transport mechanism of the sample holder to the container and the supercritical drying process.

  As a drying treatment according to the present invention, a step of installing a sample holder mounted with a substrate having a microstructure immersed or wet in a rinsing liquid in a high-pressure vessel, and a high pressure gas at normal temperature and normal pressure in the high-pressure vessel Below, a step of introducing a fluid to be a liquid to a set pressure in a liquid or supercritical state, and the high-pressure vessel is inclined and the rinsing liquid is introduced into the high-pressure vessel through a specific passage of the sample holder formed by the inclination. Collecting the rinse liquid collected above or below the at least one outlet provided on the upper or lower side of the inclined high-pressure vessel, and critical pressure of the fluid Increasing the temperature of the fluid above the critical temperature while maintaining the pressure or higher, and discharging the fluid while maintaining the temperature of the fluid above the critical temperature; It is preferred to have sequentially.

  It is preferable to have a step of collecting the rinsing liquid on the upper side or the lower side in the inclined high-pressure vessel by rotational vibration in the inclined rotation direction of the high-pressure vessel inclined on the high-pressure vessel.

  In addition, the present invention preferably includes a step of tilting the high-pressure vessel and collecting the rinse liquid on the substrate on the upper side or the lower side in the tilted high-pressure vessel by rotational vibration in the tilt rotation direction.

  A step of changing at least one of the temperature and pressure of the fluid to change the specific gravity of the fluid in the step of collecting the rinse liquid on the upper side or the lower side in the high-pressure vessel; Introducing the fluid from the lower part of the holder, controlling the temperature of the fluid between the step of discharging the rinse liquid and the step of bringing the fluid into a critical state, or a vortex flow due to a change in the specific gravity of the rinse liquid and the fluid It is preferable to generate convection to promote replacement of the fluid and the rinse liquid.

  In the step of collecting the rinse liquid on the upper side or the lower side in the high-pressure vessel, the inclination angle of the high-pressure vessel is set to 15 to 75 degrees, and the vibration angle in the vibration is within a range of ± 5 to ± 15 degrees. It is preferable that the number of vibrations is 1 to 10 times, and the fluid is liquefied carbon dioxide.

  As a drying processing apparatus according to the present invention, a high-pressure container in which a substrate having a fine structure immersed or wet in a rinsing liquid is mounted and installed on a sample holder, and a fluid that is a gas at normal temperature and normal pressure and a liquid at high pressure Fluid storage container for storing in a liquid or supercritical state, means for inclining the high-pressure container, and upper or lower side of the high-pressure container for discharging the rinse liquid collected on the upper or lower side in the inclined high-pressure container The sample holder has an inclined groove provided outward from the mounting surface of the substrate, and the rinse liquid is passed through the inclined groove on the upper side of the high-pressure vessel. Or it is preferable to collect on the lower side.

  A temperature or pressure adjusting means for changing at least one of the temperature and pressure of the fluid in the high-pressure vessel to change the specific gravity of the fluid; a pump for pumping the fluid to the high-pressure vessel; and an upper side of the sample holder And a temperature controller that controls the temperature of the substrate on at least one of the lower side, a pressure control device that controls the pressure of the fluid introduced into the high-pressure vessel, and a pressure increase in the high-pressure vessel when the fluid is introduced into the high-pressure vessel It is preferable to have a step-up speed control means for controlling the speed.

  The sample holder according to the present invention has a predetermined shape so that a set position with respect to the liquid processing container is always set in a fixed direction, and the rinse is performed through an inclined groove provided on the mounting surface side of the object to be processed. In the drying process, the liquid is collected on the upper side or the lower side of the high-pressure vessel, and the inclined groove inclines the high-pressure vessel from a predetermined position of a contact portion of the mounting portion of the workpiece to the outside. It is preferably formed of a resin that is resistant to the above-described etching solution and organic solvent.

  As described above, in the present invention, the wet etching step with the etching solution before the supercritical drying step, the pure water replacement step and the pure water rinsing step of the etching solution with pure water, the organic solvent replacement step of the pure water rinsing solution with an organic solvent. Are processed in the same processing container and sample holder, and are out of control that occurred when conventional sequential processing objects were subjected to etching processing or replacement processing with organic solvents via the atmosphere. Pattern collapse and sticking are avoided, and the disadvantage that drying results with good reproducibility cannot be obtained can be solved.

  Further, in the present invention, the surface width of the resist, etc. after exposure, development and rinsing for manufacturing LSI etc. on a large scale is 100 nm or less, and further, the pattern width is 70 nm or less, especially the pattern width (space width) is 30 nm or less. The MEMS element structure with a large-diameter substrate of 100 mm or more in diameter and silicon having a structure and low hydrophilicity can be uniformly dried in a shorter time without pattern collapse or sticking. Therefore, it has a processing speed that can be applied to a device manufacturing line. Hereinafter, the best mode for carrying out the present invention will be described with reference to specific examples.

  FIG. 1 is a cross-sectional view showing a state in which an etching process is performed by a microstructure processing apparatus according to the present invention. An object to be processed 102 is placed on a sample holder 103 to be described later, and the object to be processed 102 placed on the sample holder 103 is processed by a sample presser 105 and a pressing plate 106 pressed by a pressing spring 107 in the sample holder 103. Is retained. The sample holder 103 is installed on a support column 108 provided in the inner container 101. A solvent circulation device that circulates a temperature control solvent 132 having a predetermined temperature between the inner container 101 and the outer container 137 is provided. In the solvent circulation apparatus, the temperature control solvent 132 is introduced from the temperature control solvent introduction pipe 119 by opening the temperature control solvent introduction valve 121 from the temperature control solvent supply pipe 120. When the introduced temperature control solvent 132 reaches the temperature control solvent discharge pipe 122 provided in the external container 137, the temperature control solvent discharge valve 123 is opened from the temperature control solvent discharge pipe 122 and passes through the temperature control solvent return pipe 124. To return. That is, the temperature control solvent introduction valve 121 and the temperature control solvent discharge valve 123 are opened during use and closed after use. In this state, the target etching solution 104 is injected into the inner container 101 so that the target etching liquid 104 does not directly hit the workpiece 102, and etching is performed for a target time.

  FIG. 2 is a cross-sectional view showing a state in which the etchant is discharged from the microstructure processing apparatus according to the present invention. After the target time etching process, the etching solution 104 passes through the etching solution discharge valve 134 opened from the etching solution / pure water / IPA discharge pipe 129 and is discharged from the etching solution discharge pipe 133. At this time, almost the entire amount of the etching solution 104 other than the sample holder 103 is discharged. After completion of the discharge, the etchant discharge valve 134 is closed.

  FIG. 3 is a cross-sectional view showing a state in which pure water is introduced into the microstructure processing apparatus according to the present invention. After the etching solution 104 is discharged, the pure water introduction valve (110) is immediately opened from the pure water introduction pipe 118, and the pure water 105 is introduced into the internal container 101 from the pure water / IPA introduction pipe 109. When the introduced pure water 105 is supplied up to the height of the pure water / IPA discharge pipe 116, it is discharged from the open pure water discharge valve 112 through the pure water discharge pipe 114. The etching solution 104 remaining in the sample holder 103 is replaced and diluted by the introduction of the initial pure water 135, and is completely replaced with the pure water 135 as time passes (supply amount).

  FIG. 4 is a cross-sectional view showing the situation when the fine structure processing apparatus is viewed from above. As shown in FIG. 4, the introduced pure water 135 has a flow in the direction of the arrow 138 inside the inner container 101 depending on the mounting angle of the plurality of disposed pure water / IPA introduction pipes 109. Further, as shown in FIG. 3, the upper shielding plate 131 installed on the upper part of the inner container 101 has a flow in the arrow direction 139 inside the inner container 101, and near the upper side of the workpiece 102 and the sample holder 103. The pure water 135 enters and contacts from an oblique direction, so that the etching solution 104 can be efficiently replaced with the pure water 135.

  FIG. 5 is a cross-sectional view showing a state in which pure water is discharged from the inside of the microstructure processing apparatus according to the present invention. After rinsing with pure water 135 for the target time, pure water 135 passes through pure water discharge valve 2 (125) opened from etchant / pure water / IPA discharge pipe 129 and is discharged from pure water discharge pipe 2 (126). Is done. At this time, almost all of the pure water 135 other than the sample holder 103 is discharged. After the completion of the discharge, the pure water discharge valve 2 (125) is closed.

  6 and 7 are cross-sectional views showing a situation where IPA is introduced into the microstructure processing apparatus according to the present invention. After the pure water 135 is discharged, the IPA introduction valve 111 is immediately opened from the IPA introduction pipe 117 and the IPA 136 is introduced from the pure water / IPA introduction pipe 109 to the internal container 101. When the introduced IPA 136 is supplied up to the height of the pure water / IPA discharge pipe 116, it is discharged from the open IPA discharge valve 113 through the IPA discharge pipe 115. The pure water 135 remaining in the sample holder 103 is replaced and diluted by the introduction of the initial IPA 136, and is completely replaced with the IPA 136 with the passage of time (supply amount).

  As shown in FIG. 4 described above, the introduced IPA 136 has a flow in the arrow direction 138 inside the inner container 101 depending on the mounting angle of the plurality of pure water / IPA introduction pipes 109 arranged. Further, as shown in FIG. 6, the upper shielding plate 131 installed on the upper part of the inner container 101 has a flow in the arrow direction 139 inside the inner container 101, and near the upper side of the workpiece 102 and the sample holder 103. The IPA 136 replacement process can be efficiently performed by the IPA 136 entering and contacting from an oblique direction.

  Furthermore, since the IPA 136 is agitated by driving the XYZ vibration device (130), the replacement efficiency can be increased.

  FIG. 8 is a cross-sectional view showing a state where the IPA replacement process by the microstructure processing apparatus according to the present invention is finished. After the IPA replacement process for the target time, the IPA 136 passes through the IPA discharge valve 2 (128) opened from the etching solution / pure water / IPA discharge pipe 129 and is discharged from the IPA discharge pipe 2 (127). At this time, almost the entire amount of the IPA 136 other than the sample holder 103 is discharged. After the IPA 136 is discharged, the IPA discharge valve 2 (127) is closed.

  After the above steps are completed, the sample holder 103 is taken out by the transport mechanism and installed in a high-pressure processing container for performing a drying process. After installation, the drying process is performed with a high-pressure vessel.

  FIG. 9 is a cross-sectional view showing an example of the fine structure drying apparatus according to the present invention. As shown in FIG. 10, a high-pressure vessel 203 in which a substrate 201 having a fine structure immersed or wet in a rinsing liquid 202 is mounted on a sample holder 204 and installed, is a gas at normal temperature and normal pressure, and is a liquid at high pressure A fluid storage container 215 for storing fluid in a liquid or supercritical state, a means for inclining the high-pressure container 203, a means for vibrating the high-pressure container 203 in an inclination direction, and an upper side or a lower side in the inclined high-pressure container 203 And a discharge port 219 provided on at least one of the upper side and the lower side of the high-pressure vessel 203 for discharging the rinse liquid 221. Further, the sample holder 204 has the inclined groove 11 provided outward from the mounting surface of the substrate 201 as will be described later.

  The high-pressure vessel 203 serving as a drying processing chamber is composed of an upper lid 205 and a lower vessel 224, and the substrate 205 is installed by opening the lid 205. The high-pressure vessel 203 has tilting means that can tilt from horizontal to vertical. The high-pressure vessel 203 is provided with rotating shafts having gears for tilting perpendicular to the paper surface on both sides of the lower container 224, and can be tilted left and right from the horizontal to 90 degrees from the horizontal to the paper surface by a motor. Is. The filter 212 and the valve 213 are fixed to the lower container 224, and are connected to the pressure control device 223 by a high-pressure flexible pipe. Further, the back pressure control valve 209 and the valve 210 are fixed to the lid 205, and the valve 217 and the pressure control valve 218 are fixed to the lower container 224, and their tips are connected by a high-pressure flexible pipe and can rotate.

  Substrate 201 has a fine structure formed on the surface through development and rinsing processes after exposure, and rinse liquid 202 is placed on the entire surface, and a sample holder 204 provided in high pressure vessel 203 is attached to sample holder 204. Installed. Above and below the sample holder 204 is a heater 206 that can control the temperature of the sample holder 204 and the carbon dioxide 215 locally or uniformly. A pump 214 and a liquid carbon dioxide container 215 are connected to the high pressure container 203 via a valve 213 by piping. The high pressure vessel 203 is connected to back pressure control valves 209 and 208 via a valve 210 and a lower portion via a valve 207, respectively. When the set pressure is exceeded, the fluid in the high pressure vessel 203 is discharged from the discharge port 219 or the discharge port 220. The rinse liquid is discharged.

  The high-pressure vessel 203 has a temperature adjustment function by circulation of a heat medium formed inside the vessel component, can control the temperature of the fluid in the range of 0 to 60 ° C., and has a fine structure in the vicinity of the substrate 201. In order to minimize the convection due to the temperature difference on the surface side, a temperature regulator 206 capable of controlling the temperature of the sample holder 204 and the carbon dioxide 215 locally or uniformly is provided above and below the sample holder 204.

  FIG. 10 is a plan view (a), a BB cross-sectional view (b), and a CC cross-sectional view (c) of the sample holder used in all steps from the etching process to the drying process according to the present invention. Although the substrate 201 is not mounted as an object to be processed in the plan view (a), (b) and (d) are cross-sectional views showing a state in which the substrate 201 is mounted. As shown in FIG. 10, the sample holder has a cup-shaped cylindrical shape, and is installed by mounting a substrate 201 having a fine structure immersed or wet in a rinsing liquid 202 in a high-pressure vessel 203, at normal temperature and normal pressure. Then, the rinsing liquid 202 can be dried and removed by a fluid that is gas and liquid under high pressure, and is formed along the direction in which the high-pressure vessel 203 is inclined outward from a predetermined position of the contact portion of the mounting portion of the substrate 201. The inclined groove 11 having a predetermined width is provided.

  The substrate 201 is in a state where no rinse liquid is placed thereon. In the sample holder 204 of this embodiment, the inclined groove 11 having a predetermined width is provided in the flat portion 19, and the four pins of the holding means provided in the high-pressure vessel 203 through the four holding guide holes 12. Is inserted and set. The substrate 201 is inserted into the substrate insertion portion 10 and fixed by the substrate holder 11 that is pressed by the two coil springs 15 through the guide pins 14 to the right through the slide groove 16. The substrate holder 21 is held by the holding holder 17. The heater escape groove 13 is inserted so as not to contact the heater escape groove 13 so that the rod-like heater 206 provided in the high-pressure vessel 203 can be brought closer to the substrate 201.

  The sample holder 204 has a predetermined shape having a part of a flat part in a cylindrical shape so that the set position with respect to the inner container 101 and the high-pressure container 203 is always set in a fixed direction. The rinsing liquid is collected on the upper side or the lower side of the high-pressure vessel 203 during the drying process through the inclined groove 11 provided on the surface side, and the inclined groove 11 is formed from a predetermined position of the contact portion of the mounting portion of the substrate 201. It is formed along the direction in which the high-pressure vessel 203 is inclined over the outside, and is made of a resin resistant to the etching solution and the organic solvent.

Hereinafter, the drying process of a present Example is demonstrated.
(1) After forming an EB resist (ZEP-7000: manufactured by ZEON Corporation) with a film thickness of 220 nm on an LSI silicon substrate having a diameter of 200 mm and drying, the pattern was drawn with an electron beam with a pattern width of 60 nm or less. A lid 205 and a lower container together with the sample holder 204 described above on which the substrate 201 having a fine structure formed thereon is mounted, which is developed for several tens of seconds with normal hexyl acetate, rinsed for several tens of seconds with a 2-propanol rinse solution 202 Four pins provided in the high-pressure vessel 203 composed of 224 are installed through the holding guide hole 12. At this time, a rinse liquid 202 made of 2-propanol soluble in liquid carbon dioxide 216 or supercritical carbon dioxide is on the entire surface of the substrate 201 with a thickness of 2 to 3 mm, 201 is immersed in the rinse liquid 202.
(2) When the substrate 201 is installed in the sample holder 204 in the high-pressure processing vessel 203, the lid 105 is opened with the high-pressure processing vessel 203 in a horizontal state, and after installation, the lid 105 is closed to bring the high-pressure processing vessel 203 into an airtight state. To do. At this time, the valves 217 and 220207 are closed.
(3) When the valve 213 is opened, liquid carbon dioxide 216 is introduced into the high-pressure vessel 203. At this time, in order not to damage the fine structure formed on the substrate 201 by the pressure control device 223 and to minimize the turbidity between the rinsing liquid 202 and the liquid carbon dioxide, the steady pressure of the liquid carbon dioxide container 215 is about 5 MPa. Are introduced at a rate of about 1 MPa / several seconds. Liquid carbon dioxide introduced into the high-pressure processing container 203 passes through the filter 212 to remove impurities. After introducing the liquid carbon dioxide container 215 to a steady pressure, the pump 214 is operated to compress and send the liquid carbon dioxide 216 to a set pressure (about 7.5 to 13 MPa).
(4) FIG. 11 is a cross-sectional view of the microstructure drying apparatus showing a state in which the high-pressure processing vessel 203 is inclined. As shown in FIG. 11, by tilting the high-pressure processing container 203 in the tilting rotation direction 225 by the tilting means, most of the 2-propanol rinse liquid 202 placed on the substrate 201 is separated from the surface of the substrate 201 and enters the high-pressure container 203. The carbon dioxide 216 in the liquid state is mixed with almost no dissolution and becomes turbid. When the specific gravity difference with the rinsing liquid 202 is large, the turbid state is stabilized relatively quickly, so that it can be tilted quickly. Further, replacement and discharge can be effectively performed by applying a slow vibration 230 several times in the same direction as the tilt rotation direction 225 from the tilted state.
(5) When the temperature of the high-pressure vessel 203 is lowered by circulation of the heat medium and controlled to about 5 ° C., the specific gravity of liquid carbon dioxide becomes 0.95 g / ml, and the specific gravity of the rinse liquid 202 made of 2-propanol 0.80 g. Since the specific gravity difference with respect to / ml is about 0.15 g / ml, the rinsing liquid 202 collects at the upper part in the inclined high-pressure processing vessel 203 as shown in FIG. The pressure increase to the set pressure (about 7.5 to 13 MPa) and the temperature decrease to 5 ° C. may be shifted simultaneously. At this time, in order to quickly separate the rinsing liquid 202 from the sample holder 204 and the substrate 201 through the inclined groove 11 described above, the entire surface of the sample holder 204 is subjected to a water-repellent treatment film or a mirror finishing process, and the flow is further improved. For this purpose, the sample holder 204 is provided with the inclined groove 11 along the direction in which the high-pressure vessel is inclined as described above.
(6) When the pressure reaches the set pressure (about 7.5 to 13 MPa), the liquid carbon dioxide 216 is pumped by the pump 214 for several tens of seconds in order to converge the turbid state of the rinse liquid 202 composed of liquid carbon dioxide and 2-propanol. Is stopped so that the flow of liquid carbon dioxide 216 does not occur in the high-pressure processing vessel 203. At the same time, in order to minimize the convection of the liquid carbon dioxide 222, the locally provided temperature controller 206 in the sample holder 204 in the high-pressure processing vessel 203 is controlled to 5 ° C.
(7) When the turbidity of the 2-propanol rinse liquid 221 and the liquid carbon dioxide 222 collected at the upper part of the inclined high-pressure processing vessel 203 is converged, the pump 214 starts pumping the liquid carbon dioxide 216 again. When the valve 210 is opened, the 2-propanol rinse liquid 221 collected in the upper part of the inclined high-pressure processing vessel 203 is selectively discharged from the back pressure control valve 209 through the discharge port 219.
(8) At this time, as can be seen from FIG. 11, the 2-propanol rinse liquid 221 gathers in the upper portion of the inclined high-pressure vessel 203 and can be discharged from the valve 210 and the back pressure control valve 209, but the outer periphery of the substrate 201. In addition, it is difficult to efficiently separate the 2-propanol rinse liquid 202 remaining between the sample holder 204 and the substrate 201. In order to separate and separate the remaining 2-propanol rinse liquid 202 from between the substrate 201 and the sample holder 204, the high-pressure vessel 203 is kept in the inclined state 230 as shown in FIG. 2 to 3 times, the inclined groove 11 provided in the sample holder 204 can be separated more effectively. The separated 2-propanol of the rinsing liquid 202 is collected at the upper portion of the high-pressure vessel 203 and discharged as described above.
(9) The temperature controllers 206 installed at the upper and lower portions of the sample holder 204 are sequentially controlled in the range of 5 to 60 ° C., so that the rinsing liquids 202 and 221 remaining in the vicinity of the fine structure and the liquid carbon dioxide 222 It is possible to reduce the replacement time by controlling the temperature and generating a vortex or convection state change by changing the density of the rinsing liquids 202 and 221 and the liquid carbon dioxide 222 to promote the replacement of the liquid carbon dioxide 222 and the rinsing liquids 202 and 221. Useful.
(10) The pumping of the liquid carbon dioxide 216 by the pump 214 is stopped, and the temperature of the high-pressure vessel 203 is raised to 35 ° C. Although the pressure in the high-pressure vessel 203 is increased, when the set pressure (about 7.5 to 13 MPa) is exceeded, the pressure is discharged from the back pressure control valve 209 and the inside of the high-pressure vessel 203 is maintained at the set pressure (about 7.5 to 13 MPa). Be drunk. With this temperature change, the state of the liquid carbon dioxide in the high-pressure vessel 203 changes to a supercritical state. This change in state does not cause the surface tension of liquid carbon dioxide to act on the microstructure.
(11) The valve 213210 is closed, the valve 217 is opened, and supercritical carbon dioxide is discharged from the pressure control valve 218 while maintaining the temperature at 35 ° C. When the pressure in the high-pressure vessel 203 becomes 7.38 MPa or less, the state of carbon oxide changes to a gas supercritically filling the high-pressure vessel 203. Further, the discharge is continued by the pressure control valve 218, and the drying is finished when the pressure in the high-pressure vessel 203 becomes the atmospheric pressure.

  In this example, carbon dioxide that is in a supercritical state at a relatively low temperature and low pressure is used as an example of the fluid used for drying the microstructure, but the critical pressure of carbon dioxide is 7.38 MPa. The critical temperature is 31 ° C. The density of liquid carbon dioxide can be changed from 0.65 to 0.95 g / ml by changing the temperature from 5 ° C. to 60 ° C. and the pressure from 3 MPa to 10 MPa. Is used as a rinsing liquid, a drying process capable of obtaining a uniform drying result in a short time can be achieved.

  According to the drying treatment of this embodiment, there is no pattern collapse or sticking to a large-diameter substrate having a fine structure formed on the surface, and it can be performed uniformly in a short time. Further, in this embodiment, the conventional critical point drying method can solve the disadvantage that the drying processing time is long and that a uniform drying result cannot be obtained for a large-diameter substrate. In addition, the resist pattern after exposure, development, rinsing, etc. for manufacturing LSI etc. on a large scale has a surface fine structure with a pattern width of 100 nm or less, a pattern width of 70 nm or less, particularly a pattern width (space width) of 30 nm or less, Since the drying process of a large-diameter substrate having a diameter of 100 mm or more can be uniformly dried in a short time without pattern collapse, it has a processing speed that can be applied to a device manufacturing line.

  FIG. 12 is a flowchart showing all steps of the etching process, the pure water replacement process, the pure water rinse process, the organic solvent replacement process, and the drying process. As shown in FIG. 12, in this example, the sample as the object to be processed is the entire process from the above-described etching process, pure water replacement process and pure water rinse process, organic solvent replacement process, and drying process with liquid carbon dioxide. Is performed using the same sample holder.

  According to the present embodiment, etching, pure water replacement and pure water rinsing, and organic solvent replacement can be performed in the same sample holder and liquid processing container, and the sample is taken out into the atmosphere and transferred to each step. Compared to the case where the sample surface is in contact with the atmosphere, the sample surface is no longer in contact with the atmosphere, and in the drying process using a supercritical fluid such as carbon dioxide, which will be described later, the fine structure is reproducibly uniform and there is no pattern collapse or sticking in a short time. Can be dried.

  In addition, by using the same sample holder, the object to be processed can be processed while immersed in the liquid used in each process, so the pattern can be applied to a large-diameter substrate with a fine structure formed on the surface. It can be dried with good reproducibility in a short time without falling over or sticking.

It is sectional drawing which shows the condition of the etching process by the fine structure processing apparatus which concerns on this invention. It is sectional drawing which shows the condition which discharged | emitted etching liquid from the inside of the fine structure processing apparatus which concerns on this invention. It is sectional drawing which shows the condition which introduced the pure water in the fine structure processing apparatus which concerns on this invention. It is sectional drawing which shows the condition which looked at the fine structure processing apparatus which concerns on this invention from the upper part. It is sectional drawing which shows the condition which discharged | emitted the pure water from the inside of the fine structure processing apparatus which concerns on this invention. It is sectional drawing which shows the condition which introduced IPA in the fine structure processing apparatus which concerns on this invention. It is sectional drawing which shows the condition of the IPA replacement process by the fine structure processing apparatus which concerns on this invention. It is sectional drawing which shows the condition which complete | finished the IPA replacement process by the fine structure processing apparatus which concerns on this invention. It is sectional drawing of the fine structure drying processing apparatus which shows an example of this invention. It is the top view of the sample holder for the microstructure dry processing apparatus of this invention, and its sectional drawing. It is sectional drawing of the fine structure drying processing apparatus after inclining the high-pressure container of this invention. It is a flowchart which shows the process process by the fine structure processing apparatus which concerns on this invention. It is sectional drawing which shows the state which carries out the IPA rinse substitution of the to-be-processed object which carried out the pure water substitution process and the pure water rinse after an etching process. It is sectional drawing which shows the state which carries out IPA rinse substitution of the to-be-processed object to which the pure water rinse was given. It is sectional drawing which shows the state which carries out IPA rinse substitution of the to-be-processed object to which the pure water rinse was given.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pure water 2, 102 ... To-be-processed object, 3 ... Tray, 4 ... IPA, 5 ... Pure water high concentration liquid, 6 ... Pure water concentration liquid, 7, 103 ... Sample holder, 8, 106 ... Holding plate , 9, 105 ... Sample holder, 10, 107 ... Push spring, 11 ... Inclined groove, 12 ... Holding guide hole, 13 ... Heater escape groove, 14 ... Guide pin, 15 ... Coil spring, 16 ... Slide groove, 17 ... Press holder 19, flat part, 20, substrate mounting part, 21, substrate holder, 22, 23, bolt, 101, inner container, 104, etching solution, 108, column, 109, pure water / IPA introduction pipe, 110 ... Pure water introduction valve, 111 ... IPA introduction valve, 112 ... Pure water discharge valve, 113 ... IPA discharge valve, 114 ... Pure water discharge pipe, 115 ... IPA discharge pipe, 116 ... Pure water / IPA discharge pipe, 117 ... IPA Introductory piping, 1 DESCRIPTION OF SYMBOLS 8 ... Pure water introduction piping, 119 ... Temperature control solvent introduction piping, 120 ... Temperature control solvent supply piping, 121 ... Temperature control solvent introduction valve, 122 ... Temperature control solvent discharge piping, 123 ... Temperature control solvent discharge valve, 124 ... Temperature Control solvent return pipe, 125 ... pure water discharge valve 2, 126 ... pure water discharge pipe 2, 127 ... IPA discharge pipe 2, 128 ... IPA discharge valve 2, 129 ... etchant / pure water / IPA discharge pipe, 130 ... Z -YZ vibrator, 131 ... upper shielding plate, 132 ... temperature control solvent, 133 ... etchant discharge pipe, 134 ... etchant discharge valve, 135 ... pure water, 136 ... IPA, 137 ... external container, 138, 139 ... arrow direction, 201 ... substrate, 202, 221300 ... rinse solution, 203 ... high pressure vessel, 204 ... sample holder, 205 ... lid, 206 ... heater, 207, 2102 3217 ... Valve, 208, 209 ... Back pressure control valve, 212 ... Filter, 214 ... Pump, 215 ... Liquid carbon dioxide container, 216, 222 ... Liquid carbon dioxide, 218 ... Back pressure control valve, 219, 220 ... Discharge port, 223 ... Pressure control device, 224 ... Lower container, 225 ... Inclination rotation direction, 230 ... Vibration direction.

Claims (19)

  After the etching process for forming the fine structure by the etching process using the etching liquid on the workpiece placed on the sample holder, the etching liquid is replaced with pure water, and then the pure water is replaced with an organic solvent, and then the processing target is processed. In a fine structure processing method for supercritical drying in which an object is taken out from the replacement processing section and the organic solvent is removed from the object to be processed by a supercritical fluid, the object to be processed is applied to all processes from the etching process to the supercritical drying. A fine structure processing method characterized in that a processing object is placed on the sample holder.   2. The processing object placed on the sample holder is introduced into a liquid processing container, an etching solution is introduced into the liquid processing container, and a microstructure is formed on the surface of the processing object by etching. An etching process, an etching liquid discharging process for discharging the etching liquid from the liquid processing container after the etching process, and pure water is introduced into the liquid processing container after the etching liquid is discharged, and the etching liquid is used by the pure water. A pure water replacement step of replacing the pure water, an organic solvent replacement step of introducing an organic solvent into the liquid treatment container after replacement with the pure water and replacing the pure water with the organic solvent, and the liquid after replacement with the organic solvent An organic solvent discharging step of discharging the organic solvent in a processing container, and the replacement treatment of the object to be processed in which the organic solvent is immersed or wet after the organic solvent is discharged. Microstructure processing method characterized in that it comprises a supercritical drying step of removing from the object to be treated with the organic solvent by from extraction supercritical fluid section.   2. The fine structure processing method according to claim 1, wherein the pure water and the organic solvent are supplied from a position lower than an installation position of the sample holder and discharged from a position lower and a position higher than the installation position of the sample holder. .   3. The microstructure processing method according to claim 2, wherein the pure water and the organic solvent are supplied from a plurality of supply ports to generate a rotating flow in the horizontal direction and a rotating flow in the vertical direction of the liquid processing container.   5. The microstructure processing method according to claim 4, wherein the speed and size of the rotating flow are controlled by changing supply pressure and flow rate of the pure water and the organic solvent.   2. The microstructure processing method according to claim 1, wherein vibration is applied to the pure water and the organic solvent when the pure water and the organic solvent are replaced.   2. The microstructure processing method according to claim 1, wherein the replacement with the organic solvent and the discharge thereof are repeated a plurality of times.   A liquid processing container that replaces the etching solution with pure water and then replaces the pure water with an organic solvent after the etching processing for forming the fine structure by the etching processing with the etching solution on the workpiece placed on the sample holder. In the fine structure processing apparatus provided, the liquid processing container includes an internal processing container having a structure in which the sample holder can be installed, an external container holding the outside thereof, and a temperature between the internal processing container and the external container. A fine structure processing apparatus comprising a solvent circulation device for circulating a controllable solvent.   9. The microstructure processing apparatus according to claim 8, wherein the internal processing container is made of a resin resistant to the etching solution and the organic solvent, and has a structure in which the sample holder can be installed.   The supply port for supplying the pure water and the organic solvent to the internal processing container is a position lower than the installation position of the sample holder, and the discharge port for discharging the pure water and the organic solvent is the sample holder. A fine structure processing apparatus, wherein the fine structure processing apparatus is arranged at a position lower and a position higher than the installation position.   11. The supply port according to claim 10, wherein the supply port is provided at a plurality of locations so that a rotational flow in a horizontal direction and a flow in an upward oblique direction with respect to the vertical direction are generated in the pure water and the organic solvent. A fine structure processing apparatus.   The upper shielding plate according to claim 10, wherein an upper shielding plate is disposed in the inner processing container so as to generate a rotational flow of the pure water and the organic solvent between the installation position of the sample holder and the discharge port in a vertical direction. A fine structure processing apparatus provided on a peripheral portion.   12. The microstructure processing apparatus according to claim 11, further comprising a rotary flow control means for changing a supply pressure and a flow rate of the pure water and the organic solvent for controlling a speed and a size of the rotary flow.   9. The microstructure processing apparatus according to claim 8, wherein a vibration device capable of vibration in the X direction, the Y direction, and the Z direction is provided at a lower portion of the outer container, and the pure water and the organic solvent are vibrated.   A liquid processing container that replaces the etching solution with pure water and then replaces the pure water with an organic solvent after the etching processing for forming the fine structure by the etching processing with the etching solution on the workpiece placed on the sample holder. In the microstructure processing apparatus provided, the sample holder is formed in a cup shape capable of holding the etching solution, pure water, and an organic solvent.   16. The liquid processing container according to claim 15, wherein the liquid processing container can be controlled in temperature between an internal processing container having a structure capable of installing the sample holder, an external container holding the outside thereof, and the internal processing container and the external container. And a solvent circulating means for circulating a suitable solvent.   16. The microstructure processing apparatus according to claim 15, wherein the sample holder is formed with an inclined groove having a predetermined width that penetrates the cup-shaped cylindrical portion from the mounting surface of the workpiece.   16. The microstructure processing apparatus according to claim 15, wherein the sample holder has a predetermined shape so that a set position with respect to the liquid processing container is always set in a fixed direction. 16. The microstructure processing apparatus according to claim 15, wherein the sample holder is made of a resin that is resistant to the etching solution and the organic solvent.

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