JP2013062358A - Dry etching apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dry etching apparatus which facilitates the manufacturing of a partition wall and improves the durability of the partition wall thereby reducing the running cost.SOLUTION: An opening 26 of a processing container 16 is closed by a partition wall 22 which is entirely or partially formed by a dielectric body. The partition wall is protected from plasma by a protection member 24 having multiple through holes 30. A lower surface of a peripheral part of the partition wall contacts with an opening end surface 20b around the opening thereby allowing the partition wall to seal the opening. A gas allocation space 34, which allocates a process gas to the respective multiple through holes, is formed between the partition wall and the protection member. A groove 44, which communicates with the gas allocation space and connects with a process gas supply source, is annularly provided at a portion of the opening end surface which contacts with the partition wall.

Description

  The present invention relates to a dry etching apparatus that uses plasma to etch a material to be processed such as a silicon wafer.

  One of apparatuses for etching the surface of a material to be processed such as a silicon wafer is a dry etching apparatus using plasma. Such a dry etching apparatus includes a processing container that forms a processing space for etching the surface of a material to be processed by plasma. The processing container is provided with an opening, and the opening is closed with a partition including a dielectric. In addition, the dry etching apparatus includes a coil that generates a high-frequency magnetic field connected to a high-frequency power source outside the partition wall. For example, a fluorine-based process gas is introduced into the processing space. When power is supplied to the coil from the high-frequency power source, electrons trapped in the high-frequency magnetic field generated by the coil act on the process gas in the processing space through the partition walls, thereby generating plasma in the processing space.

  In such a dry etching apparatus, the partition wall is gradually scraped by the plasma. When the partition wall is cut and thinned, the partition wall will eventually be damaged without being able to withstand a load such as vacuum pressure. Therefore, it is conceivable to periodically replace the partition wall with a new one before the partition wall breaks.

  As a material for the partition wall, a quartz plate material having a certain thickness is used. Since such a material is relatively expensive, the frequent replacement of the partition walls increases the running cost of the dry etching apparatus. For this reason, conventionally, a protective member that shields the plasma so as to protect the partition walls is disposed inside the processing vessel with respect to the partition walls. Then, by replacing the protective member instead of the partition, the running cost of the dry etching apparatus is suppressed.

  Such a partition or protective member is provided with a gas discharge part for discharging process gas into the processing space. By providing the gas release part in the partition wall or the like, the process gas released from the gas release part toward the processing space can be immediately turned into plasma by the high frequency magnetic field passing through the partition wall.

  At this time, if a pipe is specially provided as an introduction path for guiding the process gas supplied from the outside to the gas discharge section provided in the partition wall or the like, the space efficiency is lowered. For this reason, a gas flow path is provided inside the partition wall to guide the process gas to the gas discharge part (see Patent Document 1). Thereby, the number of parts is also reduced.

JP 2005-209885 A

  However, in the dry etching apparatus of Patent Document 1, in order to provide the gas flow path inside the partition wall, the partition wall has a structure in which, for example, two quartz plates are bonded together, and the quartz plates to be bonded face each other. A groove is provided on the surface. Such a partition has a complicated structure and requires advanced techniques for processing. For this reason, processing takes a long time, and material loss may occur due to failure of the processing. Therefore, the partition wall was quite expensive.

  Furthermore, the strength of the quartz plate or the like may be reduced by providing a groove on the surface of the quartz plate or the like that is the material of the partition wall. When the durability of the partition walls decreases, the partition replacement cycle is shortened. Therefore, the running cost of the dry etching apparatus further increases.

  An object of the present invention is to provide a dry etching apparatus in which running costs are reduced by facilitating the manufacture of partition walls and improving the durability thereof.

One aspect of the present invention forms a processing space in which a material to be processed is disposed and a process gas is introduced, and an opening that communicates the processing space with the outside is provided at an upper portion, and an inner peripheral wall in the vicinity of the opening A processing container having a protrusion protruding inward from the inside,
A plate-like partition wall that closes the opening, all or part of which is made of a dielectric;
A high-frequency magnetic field generation unit that generates a high-frequency magnetic field that is introduced into the processing space via the dielectric and converts the process gas into plasma; and a peripheral portion that engages with the protrusion while being fitted inside the opening. By combining, a dry etching apparatus comprising a plate-like protection member that is held inside the opening and protects the partition wall from the plasma,
The opening is hermetically sealed by the partition when the lower surface of the peripheral edge of the partition comes into contact with the opening end surface around the opening, and a gas distribution space is provided between the partition and the protective member inside the opening. Is formed,
The protective member has a plurality of through holes that discharge the process gas in the gas distribution space toward the processing space,
In the dry etching apparatus, a groove that communicates with the gas distribution space and is connected to a process gas supply source is annularly provided at a portion of the opening end surface that contacts the partition wall.

  According to the present invention, not the space inside the partition wall but the space between the partition wall and the protective member is used as an introduction path for introducing the process gas into the plurality of through holes that discharge the process gas toward the processing space. Is done. Thereby, the structure of a partition can be simplified. As a result, since the partition wall can be made inexpensive and highly durable, the running cost of the dry etching apparatus can be reduced. In addition, by providing a groove communicating with the gas distribution space for temporarily retaining the process gas on the opening end surface of the processing container, it is possible to equalize the pressure of the process gas supplied from the outside. Become. Therefore, it becomes easy to control the pressure of the process gas discharged from the plurality of through holes. As a result, a uniform etching process can be easily realized.

It is a partial sectional view when the dry etching apparatus concerning one embodiment of the present invention is seen from the front. It is a top view of the part around the opening of a processing container. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2 when a partition wall and a protective member are attached to the opening of the processing container. FIG. 2 is a partial cross-sectional view similar to FIG. 1 when an upper end portion of a processing container is rotated together with a partition wall and a protective member. FIG. 5 is a bottom view of the upper end of the processing container as viewed from the side opposite to FIG. 2 in the state of FIG. 4.

  The present invention forms a processing space in which a processing material is introduced and a processing gas is introduced, and an opening that communicates the processing space and the outside is provided in an upper portion, and from the inner peripheral wall near the opening toward the inside A processing vessel having protruding protrusions, a plate-shaped partition wall that closes the opening, all or part of which is made of a dielectric, and a high frequency that is introduced into the processing space via the dielectric and converts the process gas into plasma A high-frequency magnetic field generating unit that generates a magnetic field, and a peripheral edge engaged with the protrusion in the state of being fitted inside the opening, so that it is held inside the opening and the partition wall is separated from the plasma. The present invention relates to a dry etching apparatus including a plate-shaped protection member to be protected.

  Here, the opening is hermetically sealed by the partition wall when the lower surface of the peripheral edge of the partition wall contacts the opening end surface around the opening. A gas distribution space is formed between the partition inside the opening and the protective member. The protective member is held inside the opening when the peripheral edge engages with the above-described protrusion while the protective member is fitted inside the opening.

  The protective member has a plurality of through holes that discharge process gas supplied from the outside toward the processing space. The gap between the partition wall and the protective member is communicated with the plurality of through holes, and becomes a gas distribution space for distributing the process gas to each of the plurality of through holes.

  A groove communicating with the gas distribution space is provided in an annular shape at a portion of the opening end surface of the processing container that contacts the partition wall. The groove is connected to an external process gas supply source, and temporarily holds the process gas supplied from the process gas supply source and supplies the temporarily held process gas to the gas distribution space. It has a function. That is, the groove has a function of making the gas pressure uniform.

  According to the above configuration, the process gas supplied from the outside is introduced into the groove provided in the opening end surface of the processing container, and the pressure is made uniform. The process gas having a uniform pressure in the groove is introduced into the gas distribution space between the partition wall and the protective member, and then distributed to the plurality of gas discharge portions, from the plurality of through holes toward the processing space. Released.

  As described above, by forming a gas distribution space between the partition wall and the protective member, special piping for guiding the process gas supplied from the outside to the through hole is provided, or the process gas is provided inside the partition wall. There is no need to form a flow path. Therefore, it is possible to effectively use the space, and it is not necessary to form a partition by bonding a plurality of quartz plates or the like, for example. Thereby, the structure of a partition can be simplified. As a result, the cost of the partition wall can be reduced and the durability can be improved. In addition, the running cost of the dry etching apparatus can be reduced.

  Furthermore, by introducing the process gas whose pressure is made uniform in the groove into the gas distribution space, it becomes easy to control the discharge pressure of the process gas discharged from the plurality of through holes. As a result, a uniform etching process can be easily realized.

  At this time, since the groove is provided on the opening end surface of the processing container, the groove can be disposed close to the gas distribution space. Therefore, it becomes easy to guide the process gas to the gas distribution space with the pressure uniformed in the groove. Since the groove is provided apart from the gas distribution space, it is possible to provide a space for equalizing the pressure of the gas independently of a protective member whose size variation due to thermal expansion is inevitable. . As described above, it becomes easy to keep the shape of the groove, which is a space for equalizing the gas pressure, constant, and as a result, it becomes easier to control the pressure of the process gas discharged from the gas distribution space.

  In a preferred embodiment of the present invention, the groove is provided so as to surround the opening of the processing container, and the groove and the gas distribution space are arranged in a uniform distribution between the partition wall and the opening end face. It is communicated through a gap.

  By providing the groove in an annular shape so as to surround the opening of the processing vessel, it is possible to introduce the process gas with uniform pressure into the gas distribution space from the periphery of the gas distribution space with uniform pressure. Become. Thereby, it becomes easy to equalize the pressure of the process gas at the periphery of the gas distribution space over the entire circumference of the gas distribution space.

  At this time, the internal pressure of the gas distribution space decreases from the peripheral edge of the gas distribution space toward the center due to the release of the process gas from the plurality of through holes. By equalizing the pressure of the process gas at the peripheral portion of the gas distribution space, it becomes easy to equalize the inclination of the internal pressure as described above in all directions from the center of the gas distribution space to the peripheral portion. Therefore, for example, it becomes easy to make the plasma density inside the processing space having a columnar shape uniform in the circumferential direction of the processing space. As a result, it becomes easy to make the degree of the etching process of each part of the material to be processed uniform.

  In one embodiment of the present invention, the uniform distribution gaps are arranged at equal intervals around the gas distribution space. The gap is preferably configured as a plurality of communication paths having the same flow path area. In this way, by using the uniform distribution gaps as a plurality of independent communication paths, it becomes easy to adjust the flow rate of the process gas supplied to the gas distribution space, and the etching uniformity is improved. improves.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic configuration of a dry etching apparatus according to an embodiment of the present invention in a partial sectional view as seen from the front. FIG. 2 is a top view of the upper portion of the processing vessel provided with an opening. 3 is an enlarged cross-sectional view taken along line III-III in FIG.

  The dry etching apparatus 10 in the illustrated example is a dry etching apparatus that etches a processing target material 12 such as a silicon wafer using plasma, and includes a processing container 16 that forms a processing space 14 for etching the processing target material 12. Prepare. In the processing space 14, the processing material 12 is disposed, and a process gas that is converted into plasma by electromagnetic waves is introduced. The processing space 14 has, for example, a cylindrical shape or a prismatic shape whose central axis is directed in the vertical direction. In the apparatus of the illustrated example, the processing space 14 has a cylindrical shape with the central axis facing the vertical direction. A stage 18 on which the material to be processed 12 is placed is provided inside the processing container 16. The processing space 14 during etching is maintained at a vacuum pressure.

  In a normal case, the workpiece 12 placed on the stage 18 is positioned at the center of the processing space 14 or near the center of gravity. The process gas is, for example, a fluorine-based gas.

  An upper end portion (hereinafter referred to as a container upper end portion) 20 of the processing container 16 is configured to be removable from the processing container 16. The container upper end 20 is a flat plate member, and an opening 26 for introducing electromagnetic waves into the processing container 16 penetrates in the center of the container upper end 20 in the thickness direction. The opening 26 has a function of introducing electromagnetic waves into the processing container 16. The space formed by the opening 26 is a hollow portion 20a for holding a protective member 24 described later.

  At an appropriate position of the side portion 16 b of the processing container 16, a loading / unloading port for loading / unloading the material 12 to / from the processing container 16 is provided. The entrance / exit is not shown. A gas exhaust port 16 d connected to an exhaust pump (not shown) is provided at the bottom 16 c of the processing container 16. Air and process gas inside the processing vessel 16 are discharged to the outside from the gas exhaust port 16d by the exhaust pump.

  The process gas is introduced into the dry etching apparatus 10 from the outside by a process gas supply unit (not shown). The amount of process gas introduced is adjusted using, for example, a control valve. The amount of gas discharged from the exhaust pump and the amount of process gas introduced are controlled by a controller (not shown) that accepts operator input and executes a predetermined software program.

  The opening 26 of the processing container 16 is closed by a partition wall 22 made of a dielectric material such as quartz. A protective member 24 that shields plasma and protects the partition wall 22 is provided on the inner side of the processing container 16 than the partition wall 22. The partition wall 22 and the protection member 24 are both circular plate materials, and are disposed so as to be coaxially overlapped with a predetermined gap D (see FIG. 3). The partition wall 22 is larger in diameter and thicker than the protective member 24.

  The partition wall 22 is placed on a portion around the opening 26 on the upper surface of the container upper end portion 20 (hereinafter referred to as an opening end surface 20b). At this time, the lower surface of the peripheral portion of the partition wall 22 (hereinafter referred to as the peripheral portion lower surface 22a) is in contact with the opening end surface 20b. On the other hand, in the state in which the protective member 24 is fitted in the opening 26, the lower surface of the peripheral edge portion is engaged with an engaging portion 40 (projecting portion) described later. Thereby, the protection member 24 is hold | maintained inside the hollow part 20a. The protection member 24 and the material to be processed 12 are separated by a predetermined distance.

  A plurality of through holes 30 penetrating in the thickness direction are formed in the protective member 24. One end of these through holes 30 opens toward the processing space 14, and the process gas supplied from the outside is discharged toward the processing space 14 from these openings. The other ends of the plurality of through holes 30 are open toward the gap D between the partition wall 22 and the protective member 24. As described above, the gap D between the partition wall 22 and the protective member 24 communicates with the plurality of through holes 30 to form a gas distribution space 34 that distributes the process gas supplied from the outside to each through hole 30. . The plurality of through-holes 30 should be provided radially at equal intervals from the center of the gas distribution space 34, provided in a uniform distribution over the entire surface of the gas distribution space 34, or provided side by side so as to draw a plurality of concentric circles. Can do.

  A predetermined number of retainers 38 can be attached to the upper surface of the container upper end portion 20, and the partition wall 22 is attached to the container upper end portion 20 by a plurality of retainers 38 in a state where the peripheral surface lower surface 22 a is in contact with the open end surface 20 b. Fixed.

  A groove 44 communicating with the gas distribution space 34 is formed in an annular shape on the opening end surface 20 b of the container upper end portion 20 so as to surround the opening 26. The groove 44 functions to make the pressure of the process gas supplied from the outside uniform. The groove 44 is provided at least a distance L (see FIG. 2) from the opening 26.

  The groove 44 is connected to an external process gas supply source (not shown) via an introduction path 45 formed inside the container upper end portion 20, and the process gas is introduced into the groove 44 through the introduction path 45. . In the illustrated example, the number of the introduction paths 45 is one, but the present invention is not limited to this, and the process gas can be introduced into the groove 44 through the plurality of introduction paths 45. In the illustrated example, the introduction path 45 opens at the bottom of the groove 44, but the present invention is not limited to this, and can be opened at the side of the groove 44.

  Further, a recess is formed in an annular shape so as to surround the groove 44 on the outer side of the groove 44 on the opening end surface 20b. An O-ring 36A (first O-ring) is fitted in the recess. The O-ring 36A is in contact with the peripheral lower surface 22a of the partition wall 22, so that the gap between the peripheral peripheral lower surface 22a and the open end surface 20b is sealed outside the groove 44. As a result, the opening 26 is sealed by the partition wall 22.

  The inner diameter of the hollow portion 20 a (opening 26) is slightly larger than the outer diameter of the protection member 24, and the thickness of the container upper end portion 20 is larger than the thickness of the protection member 24. Thereby, the entire protection member 24 can be accommodated in the hollow portion 20a.

  An upper end surface (hereinafter referred to as a side upper end surface) 16 f of the side portion 16 b of the processing container 16 is formed in a flat surface so as to be in close contact with the lower surface of the container upper end portion 20. The side upper end surface 16f also has a recess formed in an annular shape, and an O-ring 36B (second O-ring) is fitted into the recess. Since the O-ring 36B contacts the lower surface of the container upper end portion 20, the gap between the lower surface of the container upper end portion 20 and the side upper end surface 16f is sealed.

  An annular flat plate-like engagement member 40 is attached to the other end opening of the hollow portion 20a (opening of the hollow portion on the lower surface of the container upper end portion 20). Around the opening of the other end of the hollow part 20a, a step equal to the thickness of the engaging member 40 is provided in an annular shape. The portion where the step is provided is coaxial with the cylindrical hollow portion 20a, and forms an annular recess in which the engaging member 40 fits without excess or deficiency.

  The engaging member 40 is fastened to the container upper end portion 20 by a predetermined number of screws 42. The inner peripheral side portion of the engaging member 40 protrudes from the periphery of the other end opening of the hollow portion 20a toward the center so as to contact the lower surface of the peripheral portion of the protection member 24 over the entire periphery. On the other hand, as described above, one end opening of the hollow portion 20a (opening of the hollow portion on the upper surface of the container upper end portion 20) is blocked by the lower surface of the partition wall 22, so that the protection member 24 includes the engagement member 40 and the partition wall 22. Is held inside the hollow portion 20a.

  A recess is provided in an annular shape at a portion of the upper surface of the engagement member 40 that contacts the protection member 24, and an O-ring 36C (third O-ring) is fitted in the recess. The O-ring 36 </ b> C contacts the lower surface of the peripheral edge of the protection member 24, so that the gap between the protection member 24 and the engagement member 40 is sealed.

  Further, the diameter of the opening 16 g of the side portion 16 b of the processing container 16 is smaller than the outer diameter of the engaging member 40. As a result, the lower surface of the engaging member 40 is overlapped with the side upper end surface 16f by a portion having a predetermined width from the outer peripheral side. And the position where the screw 42 fastens the engaging member 40 to the container upper end 20 is set to the position where the head of the screw 42 overlaps the side upper end surface 16f. As a result, in a state where the container upper end portion 20 is attached to the processing container 16, the head of the screw 42 is not exposed to the processing space 14, but is covered with the side upper end surface 16f. As a result, it is possible to prevent foreign matter generated by the plasma from acting on the head of the screw 42 from entering the processing space 14.

  Next, the groove 44 will be further described. The groove 44 temporarily retains the process gas, whereby the pressure of the process gas is made uniform inside the groove 44. As described above, the groove 44 and the gas distribution space 34 are separated from each other by at least the distance L, and a predetermined number (in the illustrated example), the flow path areas are equal to each other in the portion between the groove 44 and the gas distribution space 34. Four) communication paths 46 are formed at equal intervals. By these communication paths 46, the groove 44 and the gas distribution space 34 are communicated with each other. Accordingly, the groove 44, the gas distribution space 34, and the communication path 46 are all in contact with one surface (lower surface) of the partition wall 22.

  As described above, the process gas is supplied from the groove 44 to the gas distribution space 34 through the plurality of communication paths 46 that are gaps of uniform distribution around the gas distribution space 34, so that the process is performed at the peripheral portion of the gas distribution space 34. The gas pressure can be made uniform. As a result, due to the release of the process gas from the through hole 30, the inclination of the internal pressure that decreases from the peripheral part of the gas distribution space 34 toward the central part is observed in almost all directions from the center of the gas distribution space 34 to the peripheral part. It can be made uniform. Thereby, it becomes easy to equalize the density of the plasma that reaches the material 12 to be processed.

  More specifically, due to the inclination of the internal pressure, the density of plasma generated from the process gas is small in the central portion of the processing space 14 and large in the peripheral portion in the vicinity of the protective member 24. However, since there is a certain distance between the protective member 24 and the material 12 to be processed, the plasma is processed into the processing space by the effect of the coil 48 described later until the plasma reaches the material 12 to be processed. It goes around from the peripheral part of 14 to the center part. Thereby, at the time when the plasma reaches the workpiece 12, the density of the plasma is made uniform from the peripheral portion to the central portion of the processing space 14.

  On the other hand, if there is a difference in the pressure of the process gas at the periphery of the gas distribution space 34, a difference occurs in the plasma density at the periphery of the processing space 14 in the vicinity of the protective member 24. The non-uniformity in the circumferential direction of such a density distribution is that the length in the circumferential direction is 6 times or more at the maximum in the radial direction (because the circumference = radius × 2 × π). Is often maintained without being eliminated by the time it reaches the workpiece 12. In such a case, the degree of the etching process is not uniform in the circumferential direction of the processing space 14.

  In the dry etching apparatus 10 of the illustrated example, the process gas is introduced into the gas distribution space 34 from the annular groove 44 disposed around the gas distribution space 34, so that the process gas is formed at the peripheral portion of the gas distribution space 34. The internal pressure can be made uniform. Thereby, the density of the plasma reaching the workpiece 12 can be easily made uniform in both the radial direction and the circumferential direction of the processing space 14. Therefore, the degree of the etching process can be made uniform in all parts of the material 12 to be processed. In the illustrated example, a plurality of communication paths 46 are provided around the gas distribution space 34. However, the present invention is not limited to this, and the gap around the entire circumference of the gas distribution space 34 is provided uniformly to extend from the groove 44. A process gas can also be introduced into the gas distribution space 34.

  Further, a coil 48 is fixed to the container upper end portion 20 by a coil support portion 50. The coil 48 is connected to a high-frequency power source (not shown) and constitutes an ICP (inductively coupled plasma) generation unit that generates a high-frequency magnetic field for converting the process gas into plasma. The high frequency magnetic field generated by the coil 48 is formed inside the processing container 16 through the opening 26. Further, a cover 51 is attached to the upper surface of the container upper end portion 20 so as to cover all of the partition wall 22, the coil 48, and the coil support portion 50.

  The coil 48 is formed by forming an elongated strip-like metal plate in a spiral shape, and is supported by the coil support portion 50 so that the axial center thereof coincides with the central axis of the partition wall 22 and the protection member 24. The coil 48 may be a single spiral as shown in the figure, or a double spiral such as a Fermat spiral.

  An internal electrode 52 is built in the stage 18, and this internal electrode 52 is also connected to a high frequency power source (not shown). By applying high frequency power to the internal electrode 52, it is possible to apply a bias that attracts the plasma generated in the processing space 14 to the stage 18 side. The stage 18 and the internal electrode 52 do not have to be separated, and the stage 18 can also be used as the internal electrode.

  Furthermore, the container upper end 20 is removed from the processing container 16 by being rotated by a rotation mechanism 28 including an electric motor 28a. In the rotation mechanism 28, an arm 28 c attached to the output rotation shaft 28 b of the electric motor 28 a is connected to one end portion of the container upper end portion 20. The arm 28c is rotated within a predetermined angle range of, for example, 90 ° or more by the rotation output of the electric motor 28a, whereby the container upper end portion 20 is attached to and detached from the processing container 16.

  FIG. 4 shows a state where the container upper end portion 20 is removed from the processing container 16. FIG. 5 shows a state where the container upper end portion 20 is viewed from the lower surface side in the state of FIG. As shown in FIG. 5, when the container upper end 20 is removed from the processing container 16, the head of the screw 42 is not covered and is exposed on the surface of the engaging member 40. Therefore, the engagement member 40 can be easily removed from the container upper end portion 20 by removing the screw 42 using a screwdriver or the like. When the engaging member 40 is removed from the container upper end portion 20, the protection member 24 can be taken out from the lower surface opening of the hollow portion 20 a of the container upper end portion 20. Therefore, the protection member 24 can be easily replaced. At this time, it is preferable to provide a notch into which a finger or the like can be inserted in the outer peripheral portion of the protective member 24 so that the protective member 24 can be easily taken out from the hollow portion 20a.

  Hereinafter, the operation of the dry etching apparatus 10 having the configuration described so far will be described.

  When the protection member 24 is replaced, the operator removes all the screws 42 with the container upper end 20 removed from the processing container 16 (the state shown in FIG. 4). And after removing the engaging member 40 from the container upper end part 20, the used protection member 24 is taken out from the other end opening of the hollow part 20a. Thereafter, an unused protective member 24 (protective member 24 before starting etching) is inserted into the hollow portion 20a, the engaging member 40 is attached to the container upper end portion 20, and the engaging member 40 is attached to the container with a screw 42. Fix to the upper end 20. Thereafter, the container upper end 20 is rotated by the rotation mechanism 28 to attach the container upper end 20 to the processing container 16.

  Next, an operator sets the unprocessed material 12 on the stage 18 through the above-described material access port. Thereafter, a process gas is introduced into the processing space 14 while being controlled by the controller so that the processing space 14 has an appropriate vacuum pressure.

  A high frequency power is supplied to the coil 48 from a high frequency power supply, and a high frequency power is supplied to the internal electrode 52 of the stage 18 from another high frequency power supply. When power is supplied to the coil 48, the coil 48 generates a high-frequency magnetic field. The generated high frequency magnetic field propagates through the dielectric of the partition wall 22 and is formed in the processing space 14. The process gas is ionized by the action of electrons supplemented by the high-frequency magnetic field, and a toroidal or donut-shaped plasma is generated in the vicinity of the partition wall 22. By applying high-frequency power to the internal electrode 52 of the stage 18, the plasma diffuses downward so as to be attracted toward the workpiece 12. Since the partition 22 and the material 12 to be processed are separated by a predetermined distance, the plasma density is made uniform during this diffusion process. When the uniformized plasma reaches the material 12 to be processed, the etching process of the material 12 to be processed is started.

  When the etching process of the processing target material 12 is completed, the operator takes out the processed target material 12 from the processing space 14 through the processing target material inlet / outlet, and then sets the unprocessed target material 12 on the stage 18. To do. Etching is performed on the set workpiece 12. When the etching process is completed, the operator takes out the processed material 12 to be processed, and thereafter repeats the setting of the unprocessed material 12, the etching process, and the removal of the processed material 12 in the same manner.

  As described above, the protective member 24 is gradually scraped while the etching process of the workpiece 12 is repeated. Since it is necessary to replace the protective member 24 when the protective member 24 becomes the minimum thickness, the operator determines the replacement timing of the protective member 24 by periodically measuring the thickness of the protective member 24 or the like. . Whether or not the protective member 24 has been cut to the minimum thickness is determined by providing a hole having the same depth as the minimum thickness on the upper surface of the portion of the protective member 24 that is easily cut by plasma, and the bottom of the hole has been removed. In addition, it can be determined that the protective member 24 has been cut to the minimum thickness.

  In the embodiment, the partition wall 22 and the protection member 24 are both flat plates made of a dielectric material, but are not limited thereto. The partition wall 22 and the protection member 24 may have a curved shape, for example. Accordingly, partition walls and protection members having shapes suitable for various high-frequency magnetic field generation units can be applied.

  In the embodiment, the coil 48 has a single or double spiral structure. However, instead of the coil 48, any coil or antenna that is normally used as a dry etching apparatus using plasma is applied. It's okay.

  Even when the opening 26 is provided in addition to the upper portion of the processing vessel 16 or when a high-frequency magnetic field generation unit other than the coil 48 is applied, the partition according to this embodiment or the modification is applied. Can

  The present invention can be applied to a dry etching apparatus that etches a substrate made of silicon or the like using plasma. The present invention is suitable for those that use a fluorine-based gas as a process gas, and is suitable for a dry etching apparatus that uses high power for deep digging or the like.

DESCRIPTION OF SYMBOLS 12 Material to be processed 14 Processing space 16 Processing container 20 Upper end part 22 Partition 24 Protection member 26 Opening 30 Through-hole 34 Gas distribution space 44 Groove 48 Coil 52 Internal electrode

Claims (3)

A processing space into which a processing gas is introduced and a processing gas is introduced is formed, and an opening that connects the processing space and the outside is provided in the upper portion, and protrudes inward from an inner peripheral wall in the vicinity of the opening. A processing container having a protrusion,
A plate-like partition wall that closes the opening, all or part of which is made of a dielectric;
A high-frequency magnetic field generation unit that generates a high-frequency magnetic field that is introduced into the processing space via the dielectric and converts the process gas into plasma; and a peripheral portion that engages with the protrusion while being fitted inside the opening. By combining, a dry etching apparatus comprising a plate-like protection member that is held inside the opening and protects the partition wall from the plasma,
The opening is hermetically sealed by the partition when the lower surface of the peripheral edge of the partition comes into contact with the opening end surface around the opening, and a gas distribution space is provided between the partition and the protective member inside the opening. Is formed,
The protective member has a plurality of through holes that discharge the process gas in the gas distribution space toward the processing space,
The dry etching apparatus, wherein a groove that communicates with the gas distribution space and is connected to a process gas supply source is provided in a ring shape at a portion of the opening end face that contacts the partition wall.   The groove is provided so as to surround the opening, and the groove and the gas distribution space communicate with each other through a gap arranged in a uniform distribution between the partition wall and the opening end surface. The dry etching apparatus according to claim 1.   3. The dry etching apparatus according to claim 2, wherein the uniformly distributed gaps are composed of a plurality of connecting passages arranged at equal intervals around the gas distribution space and having the same channel area.

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