JP2012009658A - Dry etching apparatus and dielectric cover for use therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dry etching apparatus in which a substrate can be etched stably at a desired etching rate immediately after an unused dielectric is attached or by simply performing dummy electrical discharge for an extremely short time.SOLUTION: A dry etching apparatus 10 comprises: a processing vessel 18 forming a processing space 16 in which a substrate 14 is arranged and process gas is introduced and provided with an opening 20 interconnecting the processing space 16 and the outside; a partition wall 22 having a dielectric attached removably to the processing vessel 18 in order to close the opening 20 when it is attached; and a coil 24 introduced into the processing space 16 through the dielectric of the partition wall 22 and generating electromagnetic waves by plasmatizing the process gas. The surface of the dielectric on the processing space side is the polishing surface.

Description

  The present invention relates to a dry etching apparatus that etches a substrate using plasma, and a dielectric cover used in the dry etching apparatus.

  One of apparatuses for etching the surface of a substrate is a dry etching apparatus using plasma. Conventionally, a dry etching apparatus includes a processing container for forming a processing space for etching the surface of a substrate with plasma, and a part of the processing container includes a partition wall made of a dielectric material made of quartz or the like (for example, (See Patent Documents 1 and 2). In addition, the dry etching apparatus is electrically connected to a high-frequency power source and includes a coil that generates an electromagnetic wave 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, electromagnetic waves generated in the coil act on the process gas in the processing space through the dielectric, thereby generating plasma in the processing space.

  In such a dry etching apparatus, the dielectric is gradually consumed and scraped off by the plasma. As the dielectric becomes thinner, the dielectric will eventually be damaged without being able to withstand a load such as its own weight. Thus, the dielectric is periodically replaced before it breaks.

JP 2005-31357 A Japanese Patent Laid-Open No. 10-167760

However, the conventional dry etching apparatus has a problem that the etching rate decreases immediately after the dielectric is replaced. In particular, this etching rate is used when a trench having a width of several μm and a via having a diameter of several tens of μm are etched on the surface of a silicon substrate using a gas mainly composed of a fluorine-based gas such as sulfur hexafluoride (SF ₆ ). The problem of lowering of the remarkably appears. For this reason, in order to stabilize the etching rate within an allowable range, a dummy discharge for 10 hours has been conventionally performed after the dielectric is replaced. Therefore, every time the dielectric is replaced, a long downtime of the plasma processing apparatus occurs due to dummy discharge.

  Although it is desired not to generate such a downtime or to shorten it, the cause of the decrease in the etching rate after replacing the dielectric has not been known so far. The inventors of the present application have completed the present invention by elucidating the cause by accumulating intensive studies.

  It is an object of the present invention to provide a dry etching apparatus capable of etching a substrate stably at a desired etching rate immediately after attaching an unused dielectric or by performing a dummy discharge for a very short time. Objective.

  In order to solve the above-described problem, according to a first embodiment of the present invention, a processing space is formed in which a substrate is disposed and a processing gas is introduced, and an opening that communicates the processing space with the outside is provided. A container, and all or part of the container is made of a dielectric, is detachable from the processing container, and closes the opening when attached to the processing container; and a dielectric that the partition has A dry etching apparatus including an electromagnetic wave generation unit that generates an electromagnetic wave that is introduced into the processing space and converts the process gas into plasma, and a surface of the dielectric on the processing space side is a polished surface.

  A second aspect of the present invention is the apparatus according to the first aspect, wherein the polished surface is a surface subjected to polishing to Ra 0.05 μm or less.

  According to a third aspect of the present invention, there is provided the apparatus according to the first or second aspect, wherein the partition wall has a dielectric, a flat plate-like main body, and the processing space side of the dielectric that the main body has. And a flat cover portion having a dielectric covering the surface.

  According to a fourth aspect of the present invention, there is provided the apparatus according to any one of the first to third aspects, wherein at least the surface of the dielectric body included in the cover portion on the side of the main body portion before the etching is started. It has a rougher surface roughness than the polished surface.

  A fifth aspect of the present invention is an apparatus according to any one of the first to fourth aspects, wherein the processing container has the opening at an upper portion.

  In order to solve the above-described problem, a sixth embodiment of the present invention is a dry etching apparatus that etches a substrate using plasma, and a cover portion that covers a dielectric that propagates electromagnetic waves for converting a process gas into plasma. And a dielectric having a polished surface on at least one surface.

  According to the present invention, the substrate can be stably etched at a desired etching rate immediately after the unused dielectric is attached or by performing a dummy discharge for a very short time.

Sectional drawing which looked at the dry etching apparatus which concerns on one Embodiment of this invention from the front Plan view of dry etching equipment (ICP unit open state) Enlarged view of the vicinity of the partition wall of the dry etching system Plan view of partition cover The figure which shows an example of the change of the etching rate after replacing | exchanging a cover part Sectional drawing of the cover part which concerns on one modification Schematic diagram showing the procedure for replacing the cover in a dry etching system Schematic diagram showing the procedure for replacing the cover in a dry etching system

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a dry etching apparatus according to an embodiment of the present invention as viewed from the front. In the embodiment, for the sake of convenience, the direction from the left to the right in FIG. 1 is the left-right direction (the positive direction of the x axis), the direction from the front to the back is the front-back direction (the positive direction of the y axis), and from the top of the page. The downward direction is described as the vertical direction (the negative direction of the z axis).

  A dry etching apparatus 10 according to the present invention is a dry etching apparatus that etches a substrate 14 using plasmas 12a and 12b. Typically, the substrate 14 to be etched is mainly made of silicon, silicon oxide film, resist, silicon nitride, or the like.

  As shown in FIG. 1, the dry etching apparatus 10 includes a processing container 18 for forming a processing space 16 for etching the substrate 14 and a flat plate made of a dielectric material such as quartz. A partition 22 that closes the opening 20 formed, and a coil 24 as an electromagnetic wave generation unit that generates an electromagnetic wave introduced into the processing space 16 through the partition 22 so as to generate plasma 12a and 12b in the processing space 16 ICP (inductively coupled plasma) unit 8. Each unit of the dry etching apparatus 10 is controlled by a controller 26 that receives input from an operator and executes a predetermined software program. The controller 26 may be appropriately provided inside or outside the dry etching apparatus 10.

  For example, the processing container 18 forms a processing space 16 having a cylindrical shape, a prismatic shape, or the like whose central axis is directed in the vertical direction. A susceptor 28 that holds the silicon substrate 14 that is an object to be etched in the processing space is fixed to the processing container 18. In the etching processing space 16, the substrate 14 supported by the susceptor 28 is disposed at a fixed position, and a process gas (etching gas) is introduced through an inlet (not shown) provided in the processing container 18. Introduced and maintained at vacuum pressure.

  In a normal case, the substrate 14 is positioned by the susceptor 28 in the vicinity of the center (or the center of gravity) in the horizontal section (cross section in the xy plane) of the processing space 16. The process gas is, for example, a fluorine-based gas, and the vacuum pressure applied to plasma etching is, for example, a high vacuum pressure.

  Further, the processing container 18 has an opening 20 communicating with the outside of the processing container 18 and the processing space 16 at an upper portion thereof, more specifically, for example, at a portion positioned above the substrate 14. Further, the processing container 18 has a partition mounting part 19 for mounting the partition 20 on the upper part surrounding the opening 20. An opening that functions as a loading / unloading port for the substrate 14 is provided between the processing space 16 and the outside of the processing container 18 at a side portion of the processing container 18, and a gate valve 30 that can be opened and closed, for example, is provided in this opening. Is provided. By opening the gate valve 30, it is possible to carry in and out the substrate 14. By closing the gate valve 30, it is possible to maintain a vacuum pressure in the processing space 16 and perform a predetermined etching process. It becomes. Although not shown, a view port (viewing window) that allows the processing space 16 to be seen from the outside of the processing container 18 may be provided on the side surface of the processing container 18.

  The partition wall 22 is a flat plate made of a dielectric material such as quartz, and is a member attached so as to close the opening 20 of the processing container 18 at a position separated from the substrate 14 supported by the susceptor 28 by a predetermined distance. is there. The partition wall 22 is mounted on the partition wall mounting portion 19 of the processing container 18 and is removed from the partition wall mounting portion 19 when a cover portion described later is replaced.

  When the partition wall 22 is attached to the partition mounting portion 19 of the processing container 18, an airtight structure is formed between the partition wall 22 and the processing container 18. The airtight structure is realized, for example, by interposing an elastic member between the partition wall 22 and the processing container 18. Thereby, the vacuum pressure in the processing space can be maintained.

  The partition wall 22 has a main body part (partition wall main body part) 36 that is a thick flat plate made of a dielectric material, and a cover part (partition wall cover part) 38 that covers the lower surface (surface on the processing space side) of the main body part 36. . The cover 38 is a flat plate made of a dielectric material, and the cover 38 is thinner than the main body 36, for example, about 4 mm.

  The surface roughness of the upper surface (surface on the main body portion side) of the cover portion 38 is about Ra 0.15 μm (in an unused state) before the etching is started. On the other hand, the lower surface (surface on the processing space side) 39 of the cover portion 38 is a polished surface whose surface is polished more finely than the upper surface of the cover portion 38 before starting the etching. The surface roughness of the polished surface is Ra 0.05 μm or less, preferably about Ra 0.03 μm.

  Here, Ra is an example of an index representing the roughness of the surface, and is called arithmetic average roughness, centerline average roughness, and specifically, a certain length in the direction of the average line from the roughness curve. A value obtained by averaging the area of the region surrounded by the average line and the roughness curve in the extracted portion by the extracted length is represented by (μm).

  The cover 38 is eroded by the plasma on the surface on the processing space side. Therefore, it is necessary to replace the eroded dielectric appropriately. As described above, since the partition wall 22 is detachably provided to the processing container 18, the replacement work of the cover portion 38 is facilitated. Moreover, by providing the cover part 38, the cost concerning replacement | exchange can be reduced rather than the case where the whole partition 22 is replaced | exchanged.

  The detailed configuration of the cover 38 will be described later with reference to FIGS.

  As shown in FIG. 1, the ICP unit 8 includes a coil 24, a partition wall pressing portion 6 that presses the partition wall 22 attached to the processing container 18 from the upper surface side of the peripheral portion, and a partition wall pressing portion 6. 24 and the cover part 7 which covers the whole. Further, the partition wall pressing portion 6 is attached to the processing container 18 via the hinge portion 5, and a configuration in which the entire ICP unit 8 can be opened and closed via the hinge portion 5 as shown in the schematic view of FIG. 7 is adopted. Has been. Further, as shown in FIGS. 1 and 7, the partition wall pressing portion 6 is provided on the clamp 4 and the partition wall pressing portion 6 provided in the processing container 18 in a state where the partition wall pressing portion 6 is disposed on the peripheral edge portion of the partition wall 22. By engaging the locking portion 3, the ICP unit 8 can be releasably fixed to the processing container 18. The partition wall pressing portion 6 is provided with a handle 2 for opening and closing the ICP unit 8.

  The coil 24 is a coil having a plurality of spiral structures as shown in FIG. 1 which is a front sectional view of the dry etching apparatus 10. In the closed state of the ICP unit 8, the coil 24 is disposed outside the processing container 18 and in the vicinity of the upper part of the partition wall 22.

  The coil 24 is electrically connected to the first high frequency power supply 40. In the case of deep digging, the coil 24 is supplied with high frequency power of about 3000 to 4000 W from the first high frequency power supply 40, which is larger than that in the case of normal machining. As a result, as indicated by virtual lines 12a and 12b indicating the plasma distribution state in FIG. 1, toroidal or donut-shaped plasma 12a is generated in the vicinity of the cover portion 38 of the processing space 16, and proceeds downward while diffusing. The plasma 12b reaches the substrate 14. As a result, the substrate 14 is etched.

  The susceptor 28 includes an internal electrode (not shown), and is provided with a second high-frequency power source 29 for supplying high-frequency power to the internal electrode. By applying high frequency power to the internal electrode of the susceptor 28 by the second high frequency power supply 29, it is possible to apply a bias that attracts the plasmas 12a and 12b generated in the processing space 16 to the susceptor 28 side.

  Here, in the dry etching apparatus 10 of FIG. 1, a top view of the partition 22, the processing container 18, and the like in a state where the ICP unit 8 is opened is shown in FIG. 2.

  As shown in FIGS. 1 and 2, in the partition wall 22, the main body portion 36 having a disk shape is formed to have a larger diameter than the cover portion 38 having a disk shape. A seal member 32 a such as an O-ring or a gasket is disposed between the lower surface side of the peripheral edge of the main body 36 and the processing container 18, and is continuous between the main body 36 of the partition wall 22 and the processing container 18. A confidential structure is formed.

  An elastic member 32 b is disposed between the cover portion 38 having a diameter slightly smaller than the main body portion 36 and the processing container 18. The elastic member 32 b is used for the purpose of functioning as a cushioning material (cushion material) between the cover portion 38 and the processing container 18. Further, as shown in FIG. 2, a plurality of ventilation portions 33 in which the elastic member 32 b is not partially disposed are provided between the cover portion 38 and the processing container 18. The space (gap) between the main body portion 36 and the cover portion 38 and the processing space 16 are ventilated through the ventilation portion 33 so that a pressure difference between the two spaces does not occur. By providing the ventilation portion 33 in this manner, it is possible to prevent the cover portion 38 from being cracked due to a pressure difference. Note that an O-ring may be used as the elastic member 32b. In this case, at least one through hole is formed in the cover portion 38, and the space between the main body portion 36 and the cover portion 38 and the processing space 16 are formed. Ensure ventilation between.

  With reference to FIG.3 and FIG.4, the detailed structure of the cover part 38 is demonstrated. FIG. 3 is an enlarged view showing the vicinity of the partition wall 22 of the plasma etching apparatus 10. FIG. 4 is a view of the cover portion 38 as viewed from above.

  As described above, the cover portion 38 is a surface whose upper surface is opposed to the main body portion 36, and the lower surface 39 is a polishing surface which is opposed to the processing space 16. As shown in the figure, a plurality of holes (bottomed holes) 42 are provided on the upper surface as depressions. Since the hole 42 is provided on the upper surface, the surface of the lower surface 39 is not roughened, and the above-described effects due to the lower surface 39 being a polished surface are not reduced.

  The hole 42 is provided in a region where erosion by plasma is likely to proceed, and has a depth equal to the minimum thickness. The minimum thickness refers to a thickness determined as a minimum thickness that the cover portion 38 should have in consideration of the structural strength of the cover portion 38. When the hole having such a depth is provided, the erosion by the plasma proceeds to the bottom surface of the hole 42 and the time when the hole 42 penetrates is the replacement time. By observing the above, it is possible to easily know the replacement time of the cover portion 38.

  Here, the region where plasma erosion is likely to proceed corresponds to a portion where high-density plasma is generated in the vicinity of the cover portion 38, and may vary depending on the shape, arrangement, and the like of the electromagnetic wave generating portion. When the electromagnetic wave generator is the coil 24 according to the present embodiment, the toroidal or donut-shaped plasma 12a is generated in the vicinity of the cover 38 as described above. Therefore, the region where plasma erosion is likely to proceed is a region 44c surrounded by concentric circles 44a and 44b having two different radii as shown in FIG. 4 when viewed from above.

  In the embodiment, the holes 42 are provided so as to be arranged in the radial direction at intervals of 90 degrees in each of the three concentric circles in the region 44c surrounded by the concentric circles 44a and 44b (see FIG. 4). Each of the holes 42 has a depth equal to the minimum thickness (see FIG. 3).

  The diameter of each of the holes 42 only needs to be such that an operator can visually recognize the replacement time via the viewport, and preferably has a size that hardly affects the structural strength of the cover portion 38. For example, it is about 0.5 to 2.0 mm.

  The operation of the dry etching apparatus 10 having the configuration described so far will be described with reference to FIG.

  An operator attaches an unused cover part 38 (cover part 38 before starting etching) to the dry etching apparatus 10 with the ICP unit 8 opened. Thereafter, the ICP unit is closed, the respective clamps 4 and the engaging portions 3 are engaged, and the peripheral portion of the partition wall 22 is pressed from the upper surface side by the partition wall pressing portion 6. Fix to the processing vessel 18.

  Next, the operator opens the gate valve 30 and sets the unprocessed substrate 14 on the susceptor 28. Thereafter, after the gate valve 30 is closed and the processing space 16 is sealed, a process gas is introduced into the processing space 16 while being controlled so that the processing space 16 has an appropriate vacuum pressure.

  High frequency power is supplied from the first high frequency power supply 40 to the coil 24, and high frequency power is supplied from the second high frequency power supply 29 to the internal electrode of the susceptor 28. When power is applied to the coil 24 from the first high frequency power supply 40, the coil 24 generates an electromagnetic wave. The electromagnetic wave propagates through the dielectric of the partition wall 22 and an electromagnetic field is generated in the processing space 16. The process gas is ionized by the action of the electromagnetic field, and a toroidal or donut-shaped plasma 12 a is generated in the vicinity of the partition wall 22. By applying high frequency power to the internal electrode of the susceptor 28, the plasma 12 a diffuses downward so as to be attracted toward the substrate 14. Since the partition wall 22 and the substrate 14 are separated by a predetermined distance, the density of the plasma 12b is made uniform during this diffusion process. When the uniformed plasma 12b reaches the substrate 14, the etching process of the substrate 14 is started.

  When the etching process of the substrate 14 is completed, the operator takes out the processed substrate 14 from the processing space 16 through the gate valve 30 and then sets the unprocessed substrate 14 on the susceptor 28. Etching is performed on the set substrate 14. When the etching process is completed, the operator takes out the processed substrate 14, and thereafter repeats the setting of the unprocessed substrate 14, the etching process, and the removal of the processed substrate 14 in the same manner.

  As described above, while the etching process of the substrate 14 is repeated, the cover portion 38 is gradually scraped. Since it is necessary to replace the cover portion 38 when the cover portion 38 reaches the minimum thickness, the operator periodically observes the hole 42 of the cover portion 38 from the opening of the gate valve 30 or the viewport, thereby covering the cover portion 38. It can be easily confirmed whether or not it is time to replace the section 38. Specifically, when the bottom surface of the hole 42 is cut by plasma and the hole 42 penetrates, the cover portion 38 is consumed by the plasma and has a minimum thickness. It can be easily known that it is time to replace the cover 38.

  When the hole 42 of the cover part 38 is penetrating, the operator performs an exchange operation for replacing the cover part 38 that has been consumed from the dry etching apparatus 10. Specifically, as shown in FIG. 7, the engagement between the clamp 4 and the locking portion 3 is released, the ICP unit 8 is lifted, and the ICP unit 8 is opened. Next, as shown in FIG. 8, the body portion 36 of the partition wall 22 is removed from the partition wall mounting portion 19 of the processing container 18, and the cover portion 38 shaved until reaching the minimum thickness is removed. Remove from 19. Thereafter, the unused cover part 38 is attached to the partition wall mounting part 19 of the processing container 18, and the main body part 36 is attached to the partition wall mounting part 19 of the processing container 18 again. At this time, the operator places the polishing surface of the unused cover part 38 on the elastic member 32b of the processing container 18 with the susceptor 28 side facing. In addition, the replacement | exchange operation | work of the sealing member 32a and the elastic member 32b is also performed as needed. Thereafter, the ICP unit 8 is closed, and the clamp 4 and the locking portion 3 are engaged to fix the ICP unit 8 to the processing container 18. Thereby, the replacement work of the cover part 38 is completed. Since the partition wall 22 is detachable from the opening 20, the operator can easily replace the cover portion 38. In addition, since the ICP unit 8 is configured to be openable and closable, the attaching / detaching work of the partition wall 22 and the forming operation of the confidential structure of the partition wall 22 can be easily performed.

  As described above, since the operator can easily know the replacement time by visual recognition, it is possible to save time and labor for measuring the thickness of the cover portion 38 as in the past. In order to measure the thickness of the cover part 38, the above replacement work, the work of measuring the thickness of the cover part 38, the work of wiping the cover part 38 before attaching, and the assembly work of attaching the partition wall 22 to the dry etching apparatus 10 And a series of operations such as introducing an etching gas into the processing space 16 to make it vacuum. Such a series of operations requires a lot of time and labor. If the replacement time can be known only by visual recognition, the time and labor can be saved, and the production efficiency can be improved. Even if the ICP unit 8 is not in the open state as shown in FIG. 7 and the hole 42 of the cover portion 38 cannot be viewed, at least the work for measuring the cover portion 38 and the wiping work among the above series of work. It becomes possible to improve production efficiency.

Here, an example (example) of the change in the etching rate after the cover portion 38 is replaced is shown in FIG. The horizontal axis indicates the time (RF discharge time (H)) during which high frequency (RF) power is supplied to the coil 24 after replacing the cover portion 38, and the vertical axis indicates the etching rate of the silicon substrate (Si etching rate (μm / min)). ). In FIG. 5, for example, an etching rate in the range of 8.5 to 11.5 μm / min is an etching rate management range that is a desirable etching rate. The etching process is a process of forming a via having a diameter of several tens of μm on the surface of the silicon substrate, and a gas mainly containing sulfur hexafluoride (SF ₆ ) was used. For comparison with the change of the etching rate of the present embodiment, the change of the etching rate of the conventional example when the conventional cover portion is used is shown.

  As can be seen from the figure, in the conventional example, the etching rate falls within a predetermined management range after performing dummy discharge for about 11 to 12 hours. However, the dry etching apparatus 10 according to the present embodiment starts immediately after the cover portion 38 is replaced. The etching rate is within a predetermined management range. This is an effect due to the fact that the surface of the new cover portion 38 on the processing space side is a polished surface. Thus, by using the surface of the cover portion 38 on the processing space side as a polished surface, the substrate can be stably etched at a desired etching rate immediately after the partition wall 22 is replaced.

  Conventionally, the cause of the decrease in the etching rate immediately after replacement of the cover portion 38 has not been clarified, but the inventors have made the cover portion 38 to be a polished surface by making the surface on the processing space side of the cover portion 38 a polished surface. It was clarified that the substrate can be etched stably at a desirable etching rate immediately after the replacement.

In the dry etching apparatus, the inner wall surface is rough to some extent because the reaction product generated by etching adheres to the inner wall surface of the processing vessel and prevents it from easily peeling off and dropping onto the upper surface of the processing object. It is said that the surface is good, and even on the surface of the cover portion 38, it is not particularly regarded as a problem to use the rough surface processed by a machine tool such as a milling machine. However, a rough surface has a surface area larger than that of a smooth surface and has many local edges, so that it has a property of being easily consumed by plasma. In addition, when the object to be processed is silicon and the cover part is quartz (SiO ₂ ), a deposit having the same component as the reaction product generated by etching is generated by the consumption of the cover part. For this reason, in the conventional cover part immediately after replacement, the amount of deposits in the processing space increases due to excessive consumption, and the apparent partial pressure of the reaction product increases on the surface of the processing object, which balances with etching. As a result, the etching rate was lowered. As the wear of the etching progresses and the surface of the cover portion becomes smooth, the amount of deposits generated is reduced, the balance between redeposition and etching becomes normal, and the etching rate falls within the predetermined management range. It is considered to be. This is considered to be the reason why the etching rate is recovered by the dummy discharge described above.

  On the other hand, since the cover portion according to this embodiment has a polished surface on the processing space side, the amount of plasma consumption does not increase even immediately after replacement, and it is necessary to perform dummy discharge for a long time. There is no.

  As described above, according to the dry etching apparatus 10 according to the present embodiment, the substrate can be stably etched at a desired etching rate immediately after the unused cover portion 38 is attached or only by performing a dummy discharge for an extremely short time. It becomes possible to do.

  As mentioned above, although one embodiment concerning the present invention was described, the present invention is not limited to the above-mentioned embodiment, and includes the following modification and those without any contradiction.

(Modifications related to partition walls)
In the embodiment, the partition wall 22 includes the main body portion 36 and the cover portion 38. However, the dry etching apparatus may include an integral partition wall. The whole integral partition may be made of a dielectric, and may be provided with a dielectric together with a frame or the like. When the partition walls are integral, the lower surface of the dielectric included in the partition walls is a polished surface. This also makes it possible to etch the substrate stably at a desired etching rate just by performing a dummy discharge for a very short time immediately after or after the replacement of the integral partition including the dielectric.

  In the embodiment, the main body 36 and the cover 38 are both flat plates made of a dielectric material, but the present invention is not limited to this. The main body portion and the cover portion may have a curved shape, for example. Accordingly, it is possible to apply a main body portion and a cover portion having shapes suitable for various electromagnetic wave generating portions.

  Further, for example, one or both of the main body part and the cover part may be formed from a frame body that fits into the opening 20 and one or a plurality of dielectrics attached to the frame body. When both have a frame, the main body portion and the cover portion are arranged such that the respective dielectrics overlap each other when viewed from above. Thereby, the part by which the dielectric material is arrange | positioned over the whole thickness direction (up-down direction) of a main-body part and a cover part will be provided, and electromagnetic waves will propagate to process space via the said part. Thus, by providing the frame, the strength of the main body and the cover can be improved.

  In the embodiment, an example in which only the surface on the processing space side of the cover portion 38 is a polishing surface has been described. However, at least the surface on the processing space side may be a polishing surface, and both surfaces of the cover portion 38 may be polishing surfaces. . As in the embodiment, only one surface of the cover portion 38 is a polished surface, that is, the surface on the main body portion side of the cover portion 38 is made rougher than the surface on the processing space side (lower surface 39). It is possible to reduce the labor and cost for manufacturing the cover portion 38 rather than the surface.

(Variation regarding cover hole)
In order to reduce the surface roughness of the lower surface of the cover portion, the hole of the cover portion is desirably provided on the upper surface as in the embodiment, but may be provided on the lower surface of the cover portion. Moreover, when the partition is integral as in one of the above-described modifications, a hole is provided on the lower surface of the integral partition. Thus, when a hole is provided in the lower surface, the hole has a depth equal to a thickness obtained by subtracting a minimum thickness from the thickness of the cover portion. As a result, when the plasma erosion progresses to the bottom of the hole, the cover portion 38 has a minimum thickness, and the operator can easily know that time as the replacement time of the cover portion.

  Although all the holes have the same depth in the embodiment, the plurality of holes may include ones having different depths. An example is shown in FIG. FIG. 6 shows a cross-sectional view of the cover part in a diameter passing through the holes 48a, 48b, 48c of the cover part 46 according to a modification. The cover portion 46 has holes 48a, 48b, 48c having different depths in the radial direction on the upper surface, and the depths of the holes 48a, 48b, 48c are gradually shallower in the radial direction. The hole 48a farthest from the center of the cover portion 46 has a depth equal to the minimum thickness. Therefore, the replacement time is when the hole 48a penetrates due to plasma erosion.

  In this case, when the erosion due to plasma proceeds, the holes gradually penetrate from the hole 48c near the center of the cover 46 to the holes 48b and 48a far from the center. Since the holes 48c and 48b penetrate before the hole 48a farthest from the center of the cover part 46 penetrates, the operator can easily know that the replacement time of the cover part 46 is approaching. The preparation for exchanging the cover part 46 can be appropriately performed. Then, when the hole 48a farthest from the center of the cover portion 46 penetrates, the operator may replace the cover portion 46.

  The depth of the hole in the cover portion is not limited to the above, and for example, holes having the same depth may be provided in the same radial direction, and holes having different depths may be provided in different radial directions. Also in this case, similarly to the above-described modified example, by setting the depth of the deepest hole to a depth equal to the minimum thickness, the operator can replace the cover part and the cover part should be replaced. You can easily know when it is time.

  Regarding the depth of the hole in the cover part, if the minimum depth differs according to the position of the cover part, for example, the distance from the center, the holes at different positions are equal to the minimum depth according to the position. It may have a depth. As a result, the operator can accurately and easily know the appropriate replacement time of the cover portion.

(Other variations)
In the embodiment, the recess is the hole 42, but may be a groove having a predetermined depth, for example. For the depth of the groove, the above-described deformation relating to the depth of the hole may be applied as appropriate. By providing the groove, as in the case of the hole, it is possible to know whether or not the cover portion is consumed up to the bottom of the groove, and the operator can easily know the replacement time of the cover portion.

  In the embodiment, the lower surface of the main body portion 36 and the upper surface of the cover portion 38 are brought into contact with each other to form the partition wall 22. However, a spacer is disposed between the lower surface of the main body portion 36 and the cover portion 38 to provide a gap for introducing a process gas. It is good also as a structure which provides the through-hole for several gas supply in the cover part 38 while providing (it is not made to contact). In this case, the cover portion 38 has a role as a cover portion that covers the surface of the main body portion 38 (dielectric) on the processing space side and a function as a shower nozzle that supplies process gas to the processing space.

  Although the opening is provided in the upper part of the processing container 18 in the embodiment, the opening may be provided in a side wall of the processing container 18 or the like.

  In the embodiment, the coil 24 has a plurality of spiral structures. However, instead of the coil 24, any conventional electromagnetic wave generation unit in a dry etching apparatus using plasma, such as a coil and an antenna, may be applied.

  Even when an opening is provided in addition to the upper part of the processing container 18 or when an electromagnetic wave generation unit other than the coil 24 is applied, the cover unit according to this embodiment or the modification may be applied. By making the surface of the cover part on the processing space side a polished surface, the substrate can be stably formed at a desired etching rate immediately after attaching an unused dielectric material or by performing a dummy discharge for a very short time. It becomes possible to etch.

  The present invention can be applied to a dry etching apparatus that etches a substrate made of silicon or the like using plasma. It is suitable for those using 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.

  8 ICP unit, 10 dry etching apparatus, 12 plasma, 14 substrate, 16 processing space, 18 processing vessel, 20 opening, 22 partition wall, 24 coil, 30 gate valve, 36 body part, 38, 46 cover part, 39 lower surface, 42 , 48a, 48b, 48c hole

Claims (6)

A processing container in which a substrate is disposed and a processing space into which a process gas is introduced is formed, and an opening that communicates the processing space and the outside is provided;
A partition wall that is entirely or partially composed of a dielectric, is detachable from the processing container, and closes the opening when attached to the processing container;
A dry etching apparatus comprising: an electromagnetic wave generating unit that generates an electromagnetic wave that is introduced into the processing space via a dielectric included in the partition wall and converts the process gas into plasma,
A dry etching apparatus, wherein a surface of the dielectric on the processing space side is a polished surface. The dry etching apparatus according to claim 1, wherein the polished surface is a surface that is polished to Ra of 0.05 μm or less. The partition is
A dielectric body, and a plate-shaped main body;
The dry etching apparatus according to claim 1, further comprising: a flat cover portion having a dielectric covering the surface of the dielectric of the main body on the processing space side. The surface on the main body side of the dielectric of the cover portion has a surface roughness rougher than that of the polished surface at least before etching is started. 2. A dry etching apparatus according to item 1. The dry etching apparatus according to claim 1, wherein the processing container has the opening at an upper portion. In a dry etching apparatus that etches a substrate using plasma, a cover portion that covers a dielectric material through which electromagnetic waves for converting process gas into plasma propagates,
A cover used for a dry etching apparatus, comprising a dielectric having a polished surface on at least one surface.

Images