JP2009032768A - Mounting table and plasma ashing processing apparatus - Google Patents

Abstract

An object of the present invention is to provide a mounting table and a plasma ashing apparatus capable of making ions incident from an oblique direction with respect to a main surface of an object to be processed without increasing the size of the apparatus.
A mounting table for mounting an object to be processed by plasma ashing, an electrode capable of generating plasma by applying a high frequency, and provided on the electrode, on an upper surface of the electrode In contrast, there is provided a mounting table comprising tilting means capable of mounting the object to be processed in a tilted state.
[Selection] Figure 1

Description

  The present invention relates to a mounting table and a plasma ashing processing apparatus.

  Plasma ashing treatment that removes resist using plasma is widely used in various industrial fields including semiconductors and liquid crystal displays. Specifically, the “plasma ashing process” was used as a mask during etching to process a circuit pattern on the surface of a substrate such as a semiconductor wafer or ion implantation (hereinafter referred to as “implantation”). In this process, the resist is decomposed and removed by reaction with oxygen plasma or the like.

  In addition, a plasma ashing treatment apparatus (hereinafter referred to as an ashing apparatus) in which a pair of electrodes are arranged in parallel in the chamber and a high frequency power source is connected to one of the electrodes, There is known an ashing device in which a single electrode is disposed and a high frequency power source is connected to the electrode, and the chamber is grounded to form a pair of electrodes (see, for example, Patent Document 1).

  In such an ashing device, a discharge is caused between a pair of electrodes to generate plasma, and the reactive gas is decomposed and activated by the generated plasma to neutral active species, ions (plus ions), electrons, etc. The ashing process is performed by causing neutral active species and ions to act on the resist.

  In this case, the generated ions are incident on the resist from a direction perpendicular to the main surface of the object to be processed by self-bias, but the resist used as the mask for the implantation has a deteriorated layer that is difficult to remove on the surface. Therefore, if ions are incident only from a direction perpendicular to the main surface of the object to be processed, a residue called “fence remaining” may remain.

  Here, a plasma etching apparatus has been proposed in which ions are incident from an oblique direction with respect to a main surface of an object to be processed (see Patent Document 2).

  The plasma etching apparatus disclosed in Patent Document 2 includes a sample stage (a stage on which the object to be processed is placed) inclined obliquely with respect to the magnetic field lines, and ions to be incident along the magnetic field lines are processed. It is possible to make the light incident from an oblique direction with respect to the main surface.

However, if the technique disclosed in Patent Document 2 is used to control the incident direction of ions in the ashing device, a device for generating magnetic lines in the vicinity of the sample table (the table on which the workpiece is placed) is required. As a result, the ashing device is increased in size. In addition, abnormal discharge may occur between the sample stage and the apparatus for generating magnetic field lines, which may generate particles.
JP 2005-251837 A JP-A-57-164986

  The present invention provides a mounting table and a plasma ashing processing apparatus that allow ions to be incident from an oblique direction with respect to the main surface of an object to be processed without increasing the size of the apparatus.

  According to one aspect of the present invention, there is provided a mounting table for mounting an object to be plasma ashed, an electrode capable of generating plasma by applying a high frequency, and provided on the electrode. There is provided a mounting table provided with tilting means capable of mounting the workpiece to be tilted with respect to the upper surface of the electrode.

  According to another aspect of the present invention, a chamber capable of maintaining an atmosphere depressurized from the atmosphere, gas introduction means for introducing a reactive gas into the chamber, and exhaust means for exhausting the inside of the chamber And a plasma ashing apparatus comprising the mounting table.

  ADVANTAGE OF THE INVENTION According to this invention, the mounting base and plasma ashing processing apparatus which can make ion incident from the diagonal direction with respect to the main surface of a to-be-processed object without causing the enlargement of an apparatus are provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
For convenience of explanation, a case where a resist formed as a mask on a wafer is subjected to an ashing process will be described as an example.

FIG. 1 is a schematic cross-sectional view for illustrating an ashing device according to a first embodiment of the invention.
As shown in FIG. 1, the ashing device 1 according to the present embodiment includes a chamber 2 capable of maintaining a reduced pressure atmosphere. A mounting table 10 for mounting and holding a wafer (object to be processed) W is disposed below the plasma P generating portion in the chamber 2.

  The mounting table 10 is provided with a lower electrode 3 that is insulated from the chamber 2, and an electrostatic chuck (not shown) for holding the wafer W is built in the lower electrode 3. A high frequency power source 7 is connected to the lower electrode 3 via a blocking capacitor 6, and the chamber 2 is grounded. For this reason, the upper part of the chamber 2 and the lower electrode 3 constitute a pair of electrodes, and the plasma P can be generated between the upper part of the chamber 2 and the lower electrode 3. The outer periphery of the lower electrode 3 is covered with an insulating ring 8.

  A gas introduction port 4 for introducing a reactive gas (ashing gas) G to the plasma P generating part is provided at the upper part of the side wall of the chamber 2, and an exhaust E for exhausting the inside of the chamber 2 at the bottom of the chamber 2. A gas exhaust port 5 is provided. A gas introduction means (not shown) is connected to the gas introduction port 4, and an exhaust means (not shown) such as a vacuum pump is connected to the gas exhaust port 5.

A tilting means 9 is provided on the upper surface of the lower electrode 3, and the upper surface of the tilting means 9 is a mounting surface for the wafer W. The tilting means 9 can be made of an insulating material, and is preferably made of, for example, quartz, alumina, yttria, etc. in consideration of plasma resistance. Note that a conductive material such as a metal coated with an insulating material such as quartz, alumina, or yttria can be used.
Here, the inclination angle θ of the inclination means 9 with respect to the end face (upper surface) of the lower electrode 3 is preferably more than 0 ° and 30 ° or less.

Next, the tilting means 9 will be further described.
Among the ions (plus ions) 46 and electrons generated in the plasma P, electrons having a light mass move quickly and immediately reach the lower electrode 3 and the wall surface of the chamber 2. The electrons that have reached the lower electrode 3 are prevented from moving by the blocking capacitor 6 and negatively charge the lower electrode 3. The charged voltage of the lower electrode 3 reaches about 400V to 1000V, which is called “cathode drop”.

On the other hand, since the chamber 2 is grounded, the movement of the reached electrons is not prevented, and the chamber 2 is hardly charged.
Then, the ions 46 move in the direction of the lower electrode 3 and the wafer W along the vertical electric field generated by the cathode drop, and are incident on the resist on the wafer W, thereby performing a physical ashing process. Incidentally, the neutral active species generated in the plasma P descends mainly due to gravity and reaches the resist on the wafer W, and a chemical ashing process is performed.

  Due to the movement of electrons as described above, a potential difference is generated between the plasma P and the lower electrode 3. Since the electrons in the plasma P move to the lower electrode 3 and the wall surface side of the chamber 2, the potential Vp of the plasma P becomes a positive potential. On the other hand, since the chamber 2 is grounded, its potential Va becomes zero (0). Further, as described above, the lower electrode 3 causes a cathode drop, and its potential (self-bias voltage) Vc becomes a negative potential. Since this potential Vc is naturally generated based on the mass difference (movement difference) between the electrons and the ions 46, a self-bias is generated in the lower electrode 3.

  When there is a potential difference between the plasma P and the lower electrode 3 as described above, ions 46 in the plasma P are attracted and a large number of ions 46 are collected. This is called an “ion sheath”. As described above, the ions 46 attracted from the plasma P are accelerated and collide with the resist on the wafer W, and an ashing process is performed. Even when the ions 46 are incident, the electrons move quickly, so another electron immediately reaches the lower electrode 3 and the cathode drop potential Vc is kept constant.

FIG. 2 is a schematic cross-sectional view for illustrating the state of ashing a resist having a deteriorated layer.
As shown in FIG. 2A, an altered layer (cured layer) formed on the surface of the resist 45 is formed on the resist 45 formed on the wafer 42 as an implantation mask and implanted with ions by implantation. ) 44 and an unmodified layer (bulk layer) 43 in which ions are not implanted under the modified layer.

  When such a resist 45 is to be removed by ashing, the ions 41 try to enter from a direction perpendicular to the end face (upper surface) of the lower electrode 3 by self-bias. Therefore, the ions 41 try to enter from a direction perpendicular to the main surface of the wafer 42 placed on the end surface (upper surface) of the lower electrode 3.

  When the resist 45 is removed by the incidence of such ions 41, the resist 45 in a direction perpendicular to the incident direction is easy to remove because it has a large area facing the incident ions, but is parallel to the incident direction. Since the direction resist 45 has a small area facing the incident ions, it is difficult to remove. For this reason, as shown in FIG. 2B, a part of the side wall (the altered layer 44) of the resist 45 that is most difficult to remove may remain as a residue 44a called “fence residue”.

  In order to suppress the “fence remaining”, if the ions are incident from a direction inclined with respect to the main surface of the wafer W, the area facing the incident ions increases, which is effective. Here, the ions 46 are incident along an electric field perpendicular to the end face (upper surface) of the lower electrode 3 generated by self-bias. Therefore, even if the end surface (upper surface) of the lower electrode 3 is inclined and the wafer W is placed on the inclined surface, the ions 46 are directed to the wafer W from the direction perpendicular to the end surface (upper surface) of the lower electrode 3. In this case, the incident light is incident from a direction perpendicular to the main surface of the wafer W.

  On the other hand, in this embodiment, since the tilting means 9 is provided between the end face (upper surface) of the lower electrode 3 and the wafer W, the wafer W has a direction against the direction of the electric field generated by self-bias. The main surface can be tilted. Therefore, since ions 46 can be incident on the resist from a direction inclined with respect to the main surface of the wafer W, the occurrence of “fence residue” is suppressed even when the resist 45 having the altered layer 44 is subjected to ashing. Ashing processing can be performed. In this case, there is no need for a device or the like for generating magnetic lines of force as in the technique disclosed in Patent Document 2, so that the size of the device is not increased.

  Further, since an inclined means 9 having at least the surface thereof made of an insulating material is provided between the end surface (upper surface) of the lower electrode 3 and the wafer W, the end surface (upper surface) of the lower electrode 3 and the wafer W There is no gap between them. Therefore, even if the wafer W is inclined so as to be separated from the end surface (upper surface) of the lower electrode 3, there is no possibility that abnormal discharge occurs between the end surface (upper surface) of the lower electrode 3 and the wafer W.

  Further, if the inclination angle θ of the inclination means 9 is more than 0 ° and 30 ° or less, it is possible to suppress the occurrence of “fence residue” even when the resist 45 having the altered layer 44 is ashed, A highly efficient ashing process can be performed.

  Further, even when ashing is performed on a resist having no deteriorated layer 44 such as a mask used during etching for processing a circuit pattern, ashing with reduced residue can be performed. Also in this case, if the inclination angle θ of the inclination means 9 exceeds 0 ° and is 30 ° or less, highly efficient ashing can be performed while suppressing the generation of residues.

Next, the operation of the ashing device 1 will be described with reference to FIGS.
First, the wafer W is loaded into the chamber 2 from a loading / unloading port provided on the side wall of the chamber 2 (not shown) by a transfer device (not shown). The loaded wafer W is transferred to the upper surface of the tilting means 9 by a transfer device (not shown). The transferred wafer W is held by an electrostatic chuck (not shown) built in the lower electrode 3. After a transfer device (not shown) is retracted out of the chamber 2, a carry-in / out port (not shown) is closed and the chamber 2 is sealed.

Next, an exhaust unit (not shown) is operated to reduce the pressure in the chamber 2 to a predetermined pressure. Then, a predetermined amount of reactive gas (ashing gas) G is introduced from the gas inlet 4 toward the space in the chamber 2 where the plasma P is generated. Here, as the reactive gas G, for example, O ₂ , a mixed gas of O ₂ and CF ₄ , etc. can be exemplified. However, the reactive gas G is not limited to these, and is matched to the resist material and process conditions. Can be changed as appropriate. A high frequency power of about 100 KHz to 100 MHz is supplied to the lower electrode 3 from the high frequency power source 7. Since the lower electrode 3 and the upper part of the chamber 2 constitute an electrode, a discharge occurs between the electrodes and plasma P is generated. The generated plasma P decomposes and activates the reactive gas G to generate neutral active species, ions, electrons, and the like. The generated neutral active species, ions, and the like act on the resist to perform an ashing process.

  In the present embodiment, since the tilting means 9 is provided, ions 46 are incident on the resist 45 from a direction tilted with respect to the main surface of the wafer W. Therefore, even when the resist 45 having the deteriorated layer 44 is subjected to the ashing process, the ashing process in which the occurrence of “residual fence” is suppressed can be performed.

  Further, since the inclination angle θ of the inclination means 9 exceeds 0 ° and is 30 ° or less, even when the resist 45 having the altered layer 44 is subjected to ashing treatment, the occurrence of “fence remaining” is suppressed, A highly efficient ashing process can be performed.

Further, even when ashing is performed on a resist having no deteriorated layer 44 such as a mask used during etching for processing a circuit pattern, ashing with reduced residue can be performed. Also in this case, since the inclination angle θ of the inclination means 9 exceeds 0 ° and is 30 ° or less, highly efficient ashing processing can be performed while suppressing the generation of residues.
Further, since an inclined means 9 having at least the surface thereof made of an insulating material is provided between the end surface (upper surface) of the lower electrode 3 and the wafer W, the end surface (upper surface) of the lower electrode 3 and the wafer W There is no risk of abnormal discharge occurring between the two.

FIG. 3 is a schematic cross-sectional view for illustrating an ashing device according to a second embodiment of the invention.
In addition, the same code | symbol is attached | subjected to the part similar to what was demonstrated in FIG. 1, and the description is abbreviate | omitted.
As described above, a potential difference is generated between the plasma P and the lower electrode 3.
If the inventor can control the dielectric constant between the plasma P and the lower electrode 3 as a result of the study, the self-bias, that is, the potential Vc of the lower electrode 3 can be controlled. I learned that I can do it.

  That is, if the dielectric constant between the plasma P and the lower electrode 3 is increased, the potential Vc of the lower electrode 3 can be increased, so that the force for attracting ions can be increased, and the incident direction of the ions is determined as a dielectric. The direction can be high.

  Therefore, if the tilting means is divided into a plurality of ranges so that the dielectric constant can be changed for each range, the incident direction of ions can be adjusted. Further, since the potential Vc of the lower electrode 3 can be changed by changing the dielectric constant, the amount of ions attracted can be changed, and the ashing rate can be adjusted. Therefore, the in-plane uniformity of the ashing process can be improved.

  As shown in FIG. 3, the tilting means 90 provided in the ashing device 25 is concentrically divided, and the tilting means 90 a provided on the outer peripheral side of the lower electrode 3 and the tilting means provided on the center side of the lower electrode 3. 90c, and an inclination means 90b provided between the inclination means 90a and the inclination means 90c. Then, by making the dielectric constants of the respective inclination means optimum for the ashing process, no residue remains and the ashing process with improved in-plane uniformity of the process can be performed.

  In the example illustrated in FIG. 3, the tilting means 90 is divided into three parts, but the invention is not limited to this, and the number of divisions can be changed as appropriate. In the example illustrated in FIG. 3, the tilting means 90 is concentrically divided. However, the present invention is not limited to this, and the form of division can be changed as appropriate. For example, it can be divided radially, or it can be divided into a grid. Further, although there may be a gap between the divided surfaces, in order to improve the in-plane uniformity of the ashing process, it is preferable that the divided surfaces are close enough to contact each other.

  The operation of the ashing device 25 is the same as that described with reference to FIG. 1 except that the tilting means 90 is divided and the dielectric constant can be changed for each divided range.

FIG. 4 is a schematic cross-sectional view for illustrating an ashing device according to a third embodiment of the invention.
FIG. 5 is a schematic cross-sectional view for illustrating a tilting means capable of controlling the dielectric constant.
In addition, the same code | symbol is attached | subjected to the part similar to what was demonstrated in FIG. 1, and the description is abbreviate | omitted.

  As shown in FIGS. 4 and 5, the tilting means 91 provided in the ashing device 26 is divided concentrically and is provided on the center side of the lower electrode 3 and the tilting means 91 a provided on the outer peripheral side of the lower electrode 3. Inclining means 91c, and inclining means 91b provided between the inclining means 91a and the inclining means 91c.

  In addition, spaces 12a, 12b, and 12c are provided inside the tilting means 91a, 91b, and 91c, respectively. The tilting means 91a, 91b, 91c are preferably made of an insulating material. However, the surface of metal or the like may be covered with an insulating material.

  Further, a control means 11 is provided for controlling the dielectric constant by supplying a substance for controlling the dielectric constant to the spaces 12a, 12b and 12c. The control means 11 includes a storage means 13 such as a tank for storing a substance for controlling the dielectric constant, and a substance for controlling the dielectric constant stored in the storage means 13 in the spaces 12a, 12b, A supply means 14 for supplying to 12c, a recovery means 15 for recovering a substance for controlling the dielectric constant supplied to the spaces 12a, 12b and 12c and returning them to the storage means 13 are provided. In addition, the arrow in a figure has shown the flow direction of the substance for controlling a dielectric constant.

  The supply means 14 is provided with a pipe 16 made of an insulator that communicates the storage means 13 and the spaces 12a, 12b, and 12c. The dielectric constant stored in the storage means 13 is on the storage means 13 side of the pipe 16. A supply 17 such as a pump is provided for pumping up a substance for controlling the above and supplying it to the spaces 12a, 12b and 12c. Further, on the downstream side of the feeder 17 (spaces 12a, 12b, 12c side), the pipes 16 are branched for each space, and the branch pipes 16a are on-off valves for opening and closing the respective pipelines. 18 is provided. In addition, although the thing which pumps up the substance for controlling a dielectric constant was illustrated as the supply device 17, it shall be what extrudes the substance for controlling the dielectric constant by raising the internal pressure of the accommodating means 13, for example. You can also. Further, when the substance for controlling the dielectric constant is in a pressurized state (for example, when the storage means 13 is a high-pressure tank such as a gas), the supply unit 17 can be omitted. .

  The recovery means 15 is provided with a pipe 19 made of an insulator that communicates the storage means 13 with the spaces 12a, 12b, and 12c. Further, on the upstream side of the pipe 19 (space 12a, 12b, 12c side), the pipe 19 is branched for each space, and the branched pipe 19a has an opening / closing valve 20 for opening and closing each pipe line. Is provided. In addition, a filter 21 is provided in the pipe 19 downstream of the on-off valve 20 so that dust and the like are removed by the filter 21 and then collected in the storage means 13. The filter 21 is not always necessary and can be omitted.

  Further, in the example illustrated in FIG. 5, the recovery is performed by being pushed out by the substance for controlling the dielectric constant newly supplied by the supply unit 14, but the pipe 19 of the recovery unit 15 is also pumped. For example, a substance for controlling the dielectric constant can be actively collected.

  Moreover, since the on-off valve 18 and the on-off valve 20 are provided for each space, the amount of the substance for controlling the dielectric constant filled in each space, that is, the dielectric constant can be individually controlled. It has become.

In the example illustrated in FIG. 5, the tilting means 91 is divided into three parts, but the invention is not limited to this, and the number of divisions can be changed as appropriate.
Further, in the case where the necessity of adjusting the in-plane uniformity of the ashing process is small because the size of the wafer W is small, the tilting means 91 can be prevented from being divided.

  In the example illustrated in FIG. 5, the tilting means 91 is concentrically divided. However, the present invention is not limited to this, and the form of division can be changed as appropriate. For example, it can be divided radially, or it can be divided into a grid. However, in consideration of controllability in the in-plane uniformity of the wafer W, it is preferable to divide it into ranges according to the distance from the center of the tilting means 91 (wafer W) as a concentric shape.

  Although there may be a gap between the divided surfaces, in order to improve the in-plane uniformity of the ashing process, it is preferable that the divided surfaces are close enough to contact each other.

  Since the substance for controlling the dielectric constant is supplied to the spaces 12a, 12b, and 12c by the control means 11, the inclination means depends on the amount of the substance filled in each space, the intrinsic dielectric constant of the substance, and the like. The dielectric constant of 91 can be controlled. Then, by controlling the dielectric constant of the tilting means 91, the self-bias, that is, the potential Vc of the lower electrode 3 can be controlled, and the control can be performed by dividing the in-plane of the wafer W. Therefore, the adjustment of the incident direction of ions and the in-plane uniformity of the ashing process can be improved.

  Here, the substance for controlling the dielectric constant is not particularly limited as long as the dielectric constant can be controlled. However, from the viewpoint of ease of supply and recovery, a substance having fluidity is preferable. As such a thing, gas, such as helium, liquid, a semi-fluid, what added the solid particle to the liquid and gas, etc. can be illustrated, for example.

  From the viewpoint of controllability of the dielectric constant, it is preferable that the dielectric constant has a certain degree of dielectric constant. Examples of such a material include an insulating fluorocarbon-based liquid (for example, Fluorinert (registered trademark) and Galden), insulating oil, insulating fluid, ultrapure water, ethylene glycol, glycerin, Examples include liquids such as those obtained by dissolving a polymer material in a solvent, liquids or gases added with fine particles of polymer material or inorganic material, and semi-fluids such as silicon grease. However, it is not necessarily limited to these, and can be changed as appropriate.

  In addition, when the insulating property of the substance for controlling the dielectric constant is low, there is a possibility that high-frequency power is transmitted to the outside through this substance. Therefore, in the case of using a low insulating material, for example, the insulating on-off valve 18 and on-off valve 20 are used, and the on-off valve 18 and on-off valve 20 are closed to confine the low insulating material in each space. It is preferable to supply high-frequency power from If the material for controlling the dielectric constant has high insulation, high-frequency power can be supplied even when this material is flowing in the pipe.

  Further, although substances having the same dielectric constant (for example, the same type of liquid) are supplied to the spaces 12a, 12b, and 12c provided in the tilting means 91a, 91b, and 91c, different dielectric constants are used for the respective spaces. It is also possible to supply a substance (for example, a substance whose type is changed or a ratio of what is added is changed).

Next, the operation of the ashing device 26 will be described.
First, prior to the loading of the wafer W and the operation of the exhaust means (not shown), the dielectric constant of the tilting means 91 is set to a predetermined value.
The substance for controlling the dielectric constant stored in the storage means 13 is pumped up by the supply device 17 and supplied to the spaces 12a, 12b, 12c. At this time, the on-off valve 18 and the on-off valve 20 are opened so that a substance for controlling the dielectric constant can be circulated and supplied to each space.

  Next, the flow rate of the substance flowing through each pipe 19a is controlled by a predetermined amount of dielectric constant in the spaces 12a, 12b, and 12c by the throttle valve 18 being throttled by a throttle means (not shown) or the valve 20 is closed. The material for is filled. At this time, the amount of the substance in the spaces 12a, 12b, and 12c can be known by measuring the difference between the supplied amount and the recovered amount, and each space is provided with means for detecting the liquid level and the like. Can also be detected.

  Next, the on-off valve 18 and the on-off valve 20 are closed, and a predetermined amount of a substance for controlling the dielectric constant is sealed in the spaces 12a, 12b, 12c, so that the dielectric constant of the tilting means 91a, 91b, 91c. Is set. That is, the dielectric constants of the tilting means 91a, 91b, 91c are determined and set by the ratio of the substance for controlling the dielectric constant in the space, the dielectric constant specific to the substance, and the like. At this time, if the on-off valve 18 and the on-off valve 20 having insulating properties are used, even if the material for controlling the dielectric constant is a low insulating material, the high-frequency power is leaked to the outside through this. There is no fear.

  If a highly insulating material is used as a material for controlling the dielectric constant, there is no risk of high-frequency power leaking to the outside, so the on-off valve 18 and on-off valve 20 have insulation properties. It may not be. Further, a material for controlling the dielectric constant can be circulated without closing the on-off valve 18 and on-off valve 20 so that a predetermined amount of the material can be filled in the spaces 12a, 12b, 12c. At this time, if the substance for controlling the dielectric constant is circulated, the temperature of the wafer W can be controlled.

  Further, by individually controlling the on-off valve 18 provided in each pipe 16a, the on-off valve 20 provided in each pipe 19a, etc., the amounts of substances in the spaces 12a, 12b, 12c can be individually controlled. Therefore, the dielectric constants of the tilting means 91a, 91b, 91c can be individually controlled.

  Therefore, since the self-bias distribution, that is, the distribution of the potential Vc of the lower electrode 3 can be controlled for each of the tilting means 91a, 91b, 91c, the ion incident direction and ashing rate can be adjusted, and no residue remains. Further, ashing processing with improved in-plane uniformity of processing can be performed.

In this way, the ashing process of the wafer W is performed after the dielectric constants of the tilting means 91a, 91b, 91c are set. Incidentally, the adjustment of the dielectric constant of the tilting means 91a, 91b, 91c can be performed even during the ashing process. For example, the dielectric constants of the tilting means 91a, 91b, 91c can be individually adjusted based on the in-plane uniformity of the ashed wafer W.
The other operations of the ashing device 26 are the same as those described with reference to FIG.

  In the present embodiment, a substance for controlling the dielectric constant by the control means 11 (for example, a fluorocarbon liquid or a liquid obtained by adding fine particles of a polymer material or an inorganic material to a liquid) is contained in the space 12a. , 12b, and 12c, the dielectric constant of the tilting means 91 is controlled by the amount of material filled in each space.

  Then, by controlling the dielectric constant of the tilting means 91, the self-bias, that is, the potential Vc of the lower electrode 3 can be controlled, and the control can be performed by dividing the in-plane of the wafer W. Therefore, the incident direction of ions and the ashing rate can be adjusted for each divided range. Therefore, the in-plane uniformity of the ashing process can be improved.

  Further, since the self-bias, that is, the potential Vc of the lower electrode 3 can be controlled without changing the plasma parameters such as high-frequency power and processing pressure, the plasma density is not affected and unexpected processing fluctuations occur. Does not occur.

  In the present embodiment, the amount of the substance that fills the space can be set together with the process conditions, etc., and can be stored in advance as a recipe in a storage means (not shown) of the ashing device 26. it can. In this way, the optimum conditions can be set quickly and flexibly even when the process conditions, the type and size of the wafer W change. As a result, productivity can also be improved.

FIG. 6 is a schematic cross-sectional view for illustrating an ashing device according to a fourth embodiment of the invention.
The same parts as those described in FIGS. 1 and 4 are denoted by the same reference numerals, and description thereof is omitted.

  The ashing device 30 according to the present embodiment is provided with an electrode 31 for measuring self-bias, that is, the potential Vc of the lower electrode 3. The upper surface of the electrode 31 is exposed toward a space where plasma is generated, and the lower end is electrically connected to the lower electrode 3. A self-bias measuring means 32 is connected between the electrode 31 and the blocking capacitor 6.

  As the self-bias measuring means 32, for example, a current flowing through the electrode 31 is measured, and the self-bias, that is, the potential Vc of the lower electrode 3 can be known based on the measured value. Further, the potential generated at the electrode 31 may be measured with a voltmeter for self-bias measurement (not shown).

  The potential measured in this way is not the same as the potential Vc of the lower electrode 3, but a certain correlation is recognized, so that the potential of the lower electrode 3 can be corrected by correcting with a correction value obtained in advance through experiments or the like. The potential Vc can be known.

  In the present embodiment, the ashing process can be performed under optimum conditions by adjusting the dielectric constant of the tilting means 91 based on the potential Vc of the lower electrode 3 measured in this way. In this case, the adjustment can be performed based on the operator's judgment, or can be automatically performed by a control unit (not shown) using parameters obtained in advance through experiments or the like. For example, even when the self-bias fluctuates due to fine adjustment of process conditions or changes with time, the ashing process can be performed under optimum conditions without changing other plasma parameters.

  For convenience of explanation, ashing processing of a semiconductor device (wafer) has been described as an application of the ashing device according to the embodiment of the present invention. For example, a liquid crystal display device, a phase shift mask, a solar cell, a MEMS (Micro Electro Mechanical) It can also be applied to ashing processing such as Systems).

  The embodiment of the present invention has been described above. However, the present invention is not limited to these descriptions.

As long as the features of the present invention are provided, those skilled in the art appropriately modified the design of the above-described embodiments are also included in the scope of the present invention.
For example, the shape, size, material, arrangement, and the like of each element included in the ashing device 1, the ashing device 25, the ashing device 26, the ashing device 30, etc. are not limited to those illustrated, but can be changed as appropriate.
Moreover, each element with which each embodiment mentioned above is combined can be combined as much as possible, and what combined these is also included in the scope of the present invention as long as the characteristics of the present invention are included.

1 is a schematic cross-sectional view for illustrating an ashing device according to a first embodiment of the invention. It is a schematic cross section for illustrating a mode that a resist which has a change layer is ashed. It is a schematic cross section for illustrating the ashing device concerning a 2nd embodiment of the present invention. It is a schematic cross section for illustrating the ashing device concerning a 3rd embodiment of the present invention. It is a schematic cross section for illustrating the inclination means which can control a dielectric constant. It is a schematic cross section for illustrating the ashing device concerning a 4th embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Ashing apparatus, 3 Lower electrode, 9 Inclining means, 9a-9c Inclining means, 10 Mounting stand, 11 Control means, 12a-12c Space, 13 Storage means, 14 Supply means, 15 Recovery means, 16 Piping, 16a Piping, 17 Feeder, 18 On-off valve, 19 Piping, 19a Piping, 20 On-off valve, 25 Ashing device, 26 Ashing device, 30 Ashing device, 31 Electrode, 32 Self-bias measuring means, 46 ions, 90 tilting means, 90a-90c tilting means 91 Inclining means, 91a to 91c Inclining means, P plasma, W

Claims (7)

A mounting table for mounting an object to be processed by plasma ashing,
An electrode capable of generating plasma by applying a high frequency;
Inclining means provided on the electrode and capable of placing the object to be processed in an inclined state with respect to the upper surface of the electrode;
A mounting table characterized by comprising:   The mounting table according to claim 1, wherein the tilting unit tilts the object to be processed with respect to the upper surface of the electrode in a range of more than 0 ° and 30 ° or less.   The mounting table according to claim 1 or 2, wherein at least the surface of the tilting means is made of an insulating material.   The mounting table according to claim 1, wherein the tilting unit is divided into a plurality of ranges, and the permittivity can be changed for each of the ranges. The tilting means has a space inside,
Storage means for storing a fluid material for controlling the dielectric constant;
Supply means for supplying the substance stored in the storage means to the space;
Recovery means for recovering the substance supplied to the space in the storage means;
The mounting table according to any one of claims 1 to 4, further comprising:   6. The mounting table according to claim 5, wherein the material having fluidity is an insulating liquid. A chamber capable of maintaining an atmosphere reduced in pressure than the atmosphere;
Gas introduction means for introducing a reactive gas into the chamber;
Exhaust means for exhausting the chamber;
The mounting table according to any one of claims 1 to 6,
A plasma ashing apparatus comprising:

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