JP2012248741A - Plasma processing apparatus, transfer carrier, and plasma processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively suppress radiant heat from a cover covering a holding sheet to a substrate in plasma processing which is performed to the substrate held by the holding sheet.SOLUTION: A transfer carrier 5 has a holding sheet 6 holding a wafer 2 and a frame 7. Protruding parts 34 are provided at a lower surface 32b of a body 32 of a cover 31 covering the holding sheet 6 and the frame 7. The protruding parts 34 penetrate through opening part 8 provided on the holding sheet 6, and tips 34a of the protruding parts 34 contact with an upper end surface 21a of an electrode part 21. A stage part 16 including the electrode part 21 is cooled by a cooling device 24.

Description

  The present invention relates to a plasma processing apparatus, a carrier, and a plasma processing method. In particular, the present invention relates to plasma processing for a substrate held on a holding sheet (conveyance carrier) with a frame.

  As a method of dicing a wafer, plasma dicing is known in which a wafer on which a resist mask is formed is subjected to plasma etching and divided into individual chips. In Patent Document 1, plasma is generated by a dry etching apparatus in a state where a wafer (substrate) is attached to a sheet (holding sheet) whose outer periphery is held by a ring-shaped frame in order to improve handling of the wafer in conveyance or the like. It is disclosed to use for dicing. After the plasma dicing, the transport carrier composed of the holding sheet and the frame is transferred to the mounter. In the mounter, the holding sheet is expanded, and the separated chips are picked up.

  If plasma concentration on the frame occurs during plasma dicing, the etching efficiency of the wafer decreases. Further, when the frame is exposed to plasma during plasma dicing, damage to the frame itself and deterioration of the holding sheet due to the frame being heated by the plasma also become a problem. Further, when plasma acts on the holding sheet during plasma dicing, deformation or alteration due to heat occurs, and the performance of the holding sheet (for example, expansion uniformity during expansion) decreases. Therefore, the frame ring and the holding sheet are covered with a cover during plasma dicing. The cover includes an opening for exposing the wafer held on the holding sheet to plasma.

JP 2009-94436 A

  If the cover is in contact with the holding sheet during the plasma dicing, the holding sheet is stuck to the cover, which causes a problem in carrying out the carrier from the dry etching apparatus. Therefore, a gap of about several mm is provided between the cover and the holding sheet during plasma dicing. That is, the cover during the plasma dicing is maintained in a floating state that is lifted from the holding sheet. The cover in the floating state is not sufficiently cooled, and the temperature rises to a high temperature of several hundred degrees Celsius.

  Radiant heat from the high-temperature cover to the wafer causes thermal damage to the wafer such as resist burning (deterioration of the resist mask due to heat). In particular, the influence of radiant heat from the cover is significant near the outer periphery of the wafer approaching the cover.

  It is an object of the present invention to effectively suppress radiant heat from a cover that covers a holding sheet to the substrate in plasma processing for a substrate held on a holding sheet with a frame.

  According to a first aspect of the present invention, there is provided a chamber capable of depressurization, a plasma source for generating plasma in the chamber, a holding sheet holding a substrate, a frame to which the holding sheet is attached, and the holding sheet. A transport carrier capable of being carried into and out of the chamber, and having an opening provided so as to penetrate in a thickness direction at a position between the substrate and the frame; and the transport carrier provided in the chamber. A stage to be mounted; a main body for covering the holding sheet and the frame; a window formed to penetrate the main body in the thickness direction; and the opening of the holding sheet protruding from the main body. A cover having a protrusion corresponding to the first position, a first position that allows the loading carrier to be loaded and unloaded from the stage away from the stage, and the book Covers the holding sheet and the frame of the transport carrier mounted on the stage, the window portion exposes the substrate held by the holding sheet, and the protruding portion opens the opening of the holding sheet. There is provided a plasma processing apparatus comprising: a cover driving mechanism that moves the cover to a second position that extends to the stage and contacts the stage.

  After the carrier carrier holding the substrate on the holding sheet is placed on the stage, the cover driving mechanism moves the cover from the first position to the second position. With the cover in the second position, a plasma is generated in the chamber by the plasma source. Plasma processing is performed on the substrate exposed from the window provided in the main body of the cover. On the other hand, the holding sheet and the frame of the transport carrier are protected by being covered with the main body of the cover. Since the protruding portion passes through the opening of the holding sheet of the transport carrier and is in contact with the stage, the cover during plasma processing can be effectively cooled by heat conduction from the cover to the stage. By cooling the cover, the radiant heat of the substrate from the cover can be effectively suppressed, and thermal damage to the substrate such as resist burning can be surely prevented.

  Preferably, the apparatus includes a cooling device for the stage having a coolant channel formed in the stage and a coolant circulation device for circulating the coolant in the coolant channel.

  By cooling the stage by circulating the refrigerant, the efficiency of heat conduction from the cover to the stage by bringing the protruding portion into contact with the stage is improved, and the cover can be cooled more effectively. Therefore, by cooling the stage with a cooling device, thermal damage to the substrate due to radiant heat from the cover can be more effectively prevented.

  It is preferable that the protruding portion is disposed in the vicinity of the peripheral edge of the window portion. Specifically, it is preferable that the shortest distance between the protruding portion and the peripheral edge of the window portion is set in a range of 3 mm to 20 mm.

  Since the peripheral portion of the window portion of the main body of the cover is closest to the substrate, the thermal radiation from this portion to the substrate is most prominent. By placing the protrusion that functions as a heat conduction path from the cover to the stage by contacting the stage, it is placed close to the periphery of the window where heat radiation to the substrate is most prominent. Can be cooled. Therefore, the thermal damage to the substrate due to the radiant heat from the cover can be more effectively prevented by disposing the protruding portion close to the periphery of the window portion of the main body.

  It is preferable that the protrusion and the opening are arranged symmetrically with respect to the center of the substrate.

  The protrusion functions as a heat conduction path from the cover to the stage by contacting the stage. By making the protrusions point-symmetric with respect to the center of the substrate, the radiant heat from the cover to the substrate can be reduced uniformly over the entire periphery of the substrate.

  It is preferable that the main body of the cover includes a concave portion that accommodates the frame of the transport carrier at the second position.

  By providing the recess for accommodating the frame, the cover in the second position is not in contact with the transport carrier. As a result, direct heat conduction from the transport carrier to the cover is cut off, so that the cover is more effectively cooled by heat conduction to the stage via the protrusions, and radiant heat from the cover to the substrate is more effective. Can be suppressed.

  According to a second aspect of the present invention, a holding sheet for holding the substrate, a frame to which the holding sheet is attached, and a position between the substrate and the frame of the holding sheet are provided so as to penetrate in the thickness direction. And a carrier having an opening through which a part of the cover that covers the holding sheet and the frame passes through and extends to the stage of the plasma processing apparatus during the plasma processing of the substrate. To do.

  According to a third aspect of the present invention, there is provided a conveyance carrier including a holding sheet, a frame to which the holding sheet is attached, and an opening provided so as to penetrate the holding sheet in the thickness direction. The substrate is held on the holding sheet of the carrier, the carrier is carried into the chamber of the plasma processing apparatus and placed on the stage, the cover is positioned at a predetermined position with respect to the stage, and the body of the cover Covering the holding sheet and the frame of the transport carrier, exposing the substrate through a window provided in the main body, and projecting a protrusion protruding from the main body through the opening of the holding sheet to the stage A plasma processing method is provided in which plasma is generated in the chamber and plasma processing is performed on the substrate exposed from the window.

  According to the present invention, in plasma processing for a substrate held by a holding sheet with a frame, a protrusion provided on a cover that covers the holding sheet passes through the opening of the holding sheet and is placed on the stage of the plasma processing apparatus. Make contact. As a result, radiant heat from the cover to the substrate can be effectively suppressed, and thermal damage to the wafer such as resist burning due to the radiant heat can be prevented.

1 is a cross-sectional view of a dry etching apparatus according to an embodiment of the present invention. The top view of the cover ring periphery of the dry etching apparatus of FIG. Sectional drawing in the II-II line of FIG. 2 (rising position). Sectional drawing in the II-II line of FIG. 2 (falling position). The enlarged view of FIG. 3A. The enlarged view of FIG. 3B. The top view of a wafer conveyance carrier. Sectional drawing in the VV line | wire of FIG. 5A. The top view of a cover. Sectional drawing in the VI-VI line of FIG. 6A. The top view which shows the 1st alternative of a wafer conveyance carrier. The top view which shows the 2nd alternative of a wafer conveyance carrier. Sectional drawing which shows the alternative of a cover ring.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  1 to 4A show a dry etching apparatus 1 which is an example of a plasma processing apparatus according to an embodiment of the present invention. In this embodiment, the dry etching apparatus 1 performs plasma dicing and subsequent ashing on the wafer (substrate) 2. Referring to FIGS. 4A and 4B, a wafer 2 that is circular in the present embodiment includes a front surface 2a on which an IC portion (not shown) and the like are formed, and a back surface 2b opposite to the front surface 2a (an IC portion is formed). Not provided). A resist mask 3 is formed on the surface 2a of the wafer 2 with a pattern for plasma dicing.

  The dry etching apparatus 1 includes a carrier 5 that can be carried into and out of a chamber 11 that can be depressurized via an inlet / outlet (not shown). Referring to FIGS. 5A and 5B, the transport carrier 5 includes a holding sheet 6 that holds the wafer 2 in a detachable manner. As the holding sheet 6, for example, a so-called UV tape that can be elastically stretched and holds the wafer 2 by adhesive force, but changes its chemical characteristics due to irradiation of ultraviolet rays and greatly reduces the adhesive force can be used. . In the drawing of the holding sheet 6, one surface is a surface having adhesiveness (adhesive surface 6a) and the other surface is a surface having no adhesiveness (non-adhesive surface 6b). The holding sheet 6 is flexible and can be easily bent by itself to hold a fixed shape. Therefore, a substantially ring-shaped and thin frame 7 is attached to the adhesive surface 6 a near the outer peripheral edge of the holding sheet 6. The frame 7 is made of, for example, metal, and has rigidity capable of holding the shape together with the holding sheet 6.

  The wafer 2 is held on the holding sheet 6 of the transport carrier 5 by sticking the back surface 2b to the adhesive surface 6a. As shown most clearly in FIG. 5A, the wafer 2 is disposed in the center of a circular area 6 c surrounded by the frame 7 on the adhesive surface 6 a of the holding sheet 6. Specifically, the position of the wafer 2 with respect to the holding sheet 6 is such that the center Cs of the circular region 6c and the center Cw of the wafer 2 (center when the wafer 2 is viewed from the front surface 2a or the back surface 2b) are substantially coincident. Is set. By disposing the wafer 2 in the center of the circular region 6 c, a wide annular region 6 d having a constant width is formed between the wafer 2 of the holding sheet 6 and the frame 7.

  In the annular region 6d portion of the holding sheet 6, a plurality (16 in the present embodiment) of openings 8 (same shape in the present embodiment) penetrating the holding sheet 6 in the thickness direction are formed. These openings 8 are arranged point-symmetrically with respect to the center Cs of the circular region 6c (the center Cw of the wafer 2). Specifically, the sixteen openings 8 have the same distance from the center Cs of the circular region 6c (the center Cw of the wafer 2) and are equal to the center Cs of the circular region 6c (the center Cw of the wafer 2). Arranged at angular intervals.

  The peripheral edge of each opening 8 has an endless closed shape and is separated from both the frame 7 and the wafer 2. In other words, the periphery of each opening 8 is defined only by the protective sheet 6. In the present embodiment, the shape of the peripheral edge of the opening 8 is relatively sharp on the side of the center Cs (center Cw of the wafer 2) of the circular region 6c, but the other portions are in the form of droplets having a substantially constant width.

  1 to 4B, an antenna (plasma source) 13 serving as an upper electrode is disposed above a dielectric wall 12 that closes the top of a chamber (vacuum vessel) 11 of the dry etching apparatus 1. The antenna 13 is electrically connected to the first high frequency power supply unit 14A. On the other hand, on the bottom side in the chamber 11, the stage unit 16 on which the transfer carrier 5 holding the wafer 2 is placed as described above is arranged. A process gas source 17 and an ashing gas source 18 are connected to the gas introduction port 11a of the chamber 11, and a decompression mechanism 19 including a vacuum pump for evacuating the chamber 11 is connected to the exhaust port 11b.

  The stage unit 16 includes an electrode unit 21 as a lower electrode that is electrically connected to the second high frequency power supply unit 14B, and an exterior unit 22 that is made of a dielectric and surrounds the outer periphery of the electrode unit 21. As will be described later, the electrode portion 21 is made of a dielectric in the vicinity of the upper end surface 21a in which the electrostatic attraction electrode 26 is built, that is, the uppermost portion, but the other portion is made of metal. The upper end surface 21 a of the electrode unit 21 and the upper end surface 22 a of the exterior unit 22 constitute a mounting surface 23 that is one horizontal plane on which the transport carrier 5 holding the wafer 2 is mounted. The transport carrier 5 is placed on the stage unit 16 with the holding sheet 6 holding the wafer 2 (adhesive surface 6 a) facing upward, and the non-adhesive surface 6 a of the holding sheet 6 is placed on the stage unit 16. It is placed on the surface 23. The transport carrier 5 is placed at a predetermined position and posture (including a rotational angle position around the center Cs of the circular region 6c of the holding sheet) with respect to the placement surface 23 of the stage unit 16 by a transport mechanism (not shown). The Hereinafter, this predetermined position and posture are referred to as normal positions.

  The dry etching apparatus 1 includes a cooling device 24 for the stage unit 16. The cooling device 24 includes a refrigerant flow path 21b formed in the electrode portion 21, and a refrigerant circulation device 25 that circulates the temperature-controlled refrigerant in the refrigerant flow path 21b.

  In the vicinity of the upper end surface 21 a of the electrode portion 21, an electrostatic chucking electrode 26 that is a monopolar type in the present embodiment is incorporated. A DC power source 27 is electrically connected to the electrostatic adsorption electrode 26.

  The chamber 11 includes a cover 31 that can be raised and lowered above the placement surface 23 of the stage unit 16. In the following description regarding the cover 31, when referring to the transport carrier 5 and the wafer 2 held by the transport carrier 5, the transport carrier 5 is assumed to be disposed at a normal position on the mounting surface 23 of the stage unit 16 unless otherwise specified. .

  As most clearly shown in FIGS. 6A and 6B, the cover 31 includes a main body 32 which is a member having a circular outer contour and a constant thin thickness. In the present embodiment, the main body 32 is made of a dielectric material such as ceramic.

  Referring also to FIGS. 4A and 4B, a window portion 33 penetrating in the thickness direction from the upper surface 32a to the lower surface 32b is provided in the central portion of the main body 32 of the cover 31 in plan view. In the present embodiment, since the shape of the wafer 2 is circular, the shape of the window 33 in plan view is correspondingly circular. Specifically, a tapered recess 32 c that gradually decreases in diameter from the upper surface 32 side toward the lower surface 32 b side is formed at the center of the main body 32, and an opening formed at the bottom of the tapered recess 32 c opens the window portion 33. It is composed. During the plasma processing, the wafer 2 held on the holding sheet 6 of the transport carrier 5 is exposed to the plasma through the window 33. Therefore, the diameter Dwi of the window 33 in plan view is set larger than the diameter Dwa of the wafer 2.

  On the other hand, portions other than the window 33 of the main body 32 of the cover 31 cover the holding sheet 6 and the frame 7 of the transport carrier 5 and protect them from plasma during plasma processing. Therefore, the outer diameter Dc of the main body 32 is set to be sufficiently larger than the outer contour of the transport carrier 5.

  As shown in FIGS. 6A and 6B, the main body 32 of the cover 31 is provided with a plurality (16 in the present embodiment) of projecting portions 34 that project downward from the lower surface 32a. These protrusions 34 pass through the opening 8 formed in the holding sheet 6 of the transport carrier 5 during the plasma processing and come into contact with the upper end surface 21 a of the electrode part 21 of the stage part 16. Accordingly, the position, number, shape, and dimensions of the protrusions 34 correspond to the openings 8.

  Referring to FIGS. 2 and 6A, the protruding portion 34 is arranged point-symmetrically with respect to the center Cwi of the window portion 33. Specifically, the 16 openings 8 have the same distance from the center Cwi of the window 33 and are arranged at equiangular intervals with respect to the center Cwi of the window 33. Further, as shown most clearly in FIG. 2, the positions of the 16 openings 8 of the holding sheet 6 of the transport carrier 5 arranged at the regular position coincide with the positions of the protrusions 34 of the cover 31. The shape of the individual protrusions 34 in plan view (periphery shape in plan view) is relatively pointed on the center Cwi side of the window 33, but the other part is in the form of a droplet having a substantially constant width, It is generally similar to the opening 8 of the holding sheet 6. However, the dimension of the discharge unit 34 in plan view is smaller than the opening 8. Therefore, as the cover 31 moves up and down, the individual protrusions 34 penetrate the corresponding openings 8 without contacting the holding sheet 6, and the tip 34 a side of the protrusion 34 contacts the upper end surface 21 a of the electrode part 21.

  A heat transfer sheet 35 is attached to the tip 34 a of each protrusion 34. In this embodiment, the heat transfer sheet 35 has conductivity and elasticity. The heat transfer sheet 35 does not necessarily have conductivity and elasticity. However, as will be described in detail later, the cover 31 is electrostatically attracted to the electrode part 21 by having conductivity, and the heat transfer sheet 35 is in close contact with the electrode part 21 at the time of electrostatic adsorption by having elasticity. From the viewpoint of the cooling efficiency of 31, it is more preferable to have conductivity and elasticity. The protrusion amount δ1 of the protrusion 34 from the main body 32 of the cover 31, that is, the distance from the lower surface 32b of the main body 32 to the heat transfer sheet 35 at the tip 34a of the protrusion 34 is the same for all the protrusions 34. Moreover, the end surface 35a of the heat-transfer sheet | seat 35 stuck to the front-end | tip 34a of each protrusion part 34 is made into the flat surface. Therefore, when the individual protrusions 34 pass through the corresponding openings 8 without contacting the holding sheet 6 by raising and lowering the cover 31, the end surfaces 35 a of the heat transfer sheets 35 at the tips 34 a of all the protrusions 34 are formed. The entirety contacts the upper end surface 21 a of the electrode portion 21.

  As shown most clearly in FIG. 6A, the protruding portion 34 is disposed in the vicinity of the peripheral edge 33 a of the window portion 33 formed in the main body 32 of the cover 31. Specifically, the shortest distance δ2 between the protruding portion 34 and the peripheral edge 33a of the window portion 33 is set to 3 mm or more and 20 mm or less.

  On the lower surface 32 a of the main body 32 of the cover 31, an annular receiving groove (concave portion) 36 is formed outside the protruding portion 34 in a plan view. The position, shape, and dimensions of the housing recess groove 36 were lowered to a position where the heat transfer sheet 35 at the tip 34a of the projecting portion 34 was in contact with the upper end surface 21a of the electrode portion 21 as described in detail later. At this time, the frame 7 of the transport carrier 5 is set to be accommodated. Specifically, when the cover 31 is lowered to this position, the position and dimensions of the receiving groove 36 so that the bottom wall 36a and both side walls 36b, 36c of the receiving groove 36 do not contact the frame 7. Is set.

  The upper ends of the drive rods 37 </ b> A and 37 </ b> B are fixed to the lower surface 32 b side of the main body 32 of the cover 31 at positions facing each other across the window 33. These drive rods 37A and 37B are driven up and down by a drive mechanism 38 conceptually shown only in FIG. The cover 31 is raised and lowered by raising and lowering the drive rods 37A and 37B. Specifically, the cover 31 is movable between a raised position (first position) shown in FIGS. 3A and 4A and a lowered position (second position) shown in FIGS. 3B and 4B.

  As shown in FIGS. 3A and 4B, the cover 31 in the raised position is located above the placement surface 23 of the stage unit 16 with a sufficient interval. Therefore, if the cover 31 is in the raised position, the operation of placing the transport carrier 5 (holding the wafer 2) on the mounting surface 23 and the operation of lowering the transport carrier 5 from the mounting surface 23 are conversely performed. Is possible.

  As shown in FIGS. 3B and 4B, when the cover 31 is in the lowered position, the holding sheet 6 (excluding the portion holding the wafer 2) of the transport carrier 5 and the frame 7 at the regular position are the main body of the cover 31. 32. Specifically, the lower surface 32b of the main body 32 is positioned above the holding sheet 6 with a gap δ3 therebetween. The frame 7 is housed in a housing groove 36 formed in the lower surface 32a of the main body 32, and does not contact any of the bottom wall 36a and both side walls 36b, 36c of the housing groove 36.

  When the cover 31 is in the lowered position (FIGS. 3B and 4B), the wafer 2 held on the holding sheet 6 of the transport carrier 5 in the normal position is exposed from the main body 32 of the cover 31 through the window 33. ing. Specifically, as shown most clearly in FIG. 4B, a gap δ 4 is formed between the peripheral edge 33 a of the window 33 and the outer peripheral edge of the wafer 2, and the wafer 2 is not in contact with the cover 31. It is.

  Further, when the cover 31 is in the lowered position (FIGS. 3B and 4B), all the protrusions 34 pass through the corresponding openings 8 formed in the holding sheet 6, and the transmission of the tips 34a of these protrusions 34 is performed. The end surface 35 a of the heat sheet 35 contacts the upper end surface 21 a of the electrode unit 21 of the stage unit 16. As described above, the protrusion 34 that penetrates the opening 8 is not in contact with the holding sheet 6.

  A control device 40 schematically shown only in FIG. 1 includes first and second high-frequency power supply units 14A and 14B, a process gas source 17, an ashing gas source 18, a decompression mechanism 19, a cooling device 24, a DC power source 27, and a drive. The operation of the elements constituting the dry etching apparatus 1 including the mechanism 38 is controlled.

  Next, operation | movement of the dry etching apparatus 1 of this embodiment is demonstrated.

  First, as shown in FIGS. 5A and 5B, the wafer 2 is adhered and held at the center of the circular region 6 c of the holding sheet 6 of the transport carrier 5. Next, the transport carrier 5 is carried into the chamber 11 by a transport mechanism (not shown) and placed at a normal position on the placement surface 23 of the stage unit 16. At this time, the cover 31 is in the raised position (FIGS. 3A and 4B).

  Next, the drive rods 37A and 37B are driven by the drive mechanism 38, and the cover 31 is lowered from the raised position (FIGS. 3A and 4A) to the lowered position (FIGS. 3B and 4B). When the cover 31 is in the lowered position, the holding sheet 6 and the frame 7 of the transport carrier 5 are covered with the main body 32 of the cover 31, and the wafer 2 is exposed from the window portion 32 of the main body 32. When the cover 31 is in the lowered position, the projecting portions 34 penetrate the corresponding openings 8, and the heat transfer sheet 35 at the tip 34 a of the projecting portion 34 contacts the upper end surface 21 a of the electrode portion 21.

  Next, a DC voltage is applied to the electrostatic chucking electrode 26 from the DC power source 27, and the wafer 2 is held on the mounting surface 23 of the stage 16 (the upper end surface 21a of the electrode unit 21) by electrostatic chucking. In addition, since the tip 34 a of the protruding portion 34 of the cover 31 that is in contact with the upper end surface 21 a of the electrode portion 21 is a heat transfer sheet 35 having conductivity, an electrostatic adsorption force also acts on the cover 31. As a result, the protruding portion 34 of the cover 31 is pressed against the upper end surface 21 a of the electrode portion 21, and the heat transfer sheet 35 is in close contact with the upper end surface 21 a of the electrode portion 21.

  Next, while introducing a process gas for plasma dicing from the process gas source 17 into the chamber 11, the process chamber 15 is evacuated by the decompression mechanism 19 to maintain the processing chamber 15 at a predetermined pressure. Thereafter, high frequency power is supplied from the high frequency power supply unit 14 </ b> A to the antenna 13 to generate plasma P in the chamber 11 and irradiate the wafer 2 exposed from the window 33 of the cover 31. At this time, a bias voltage is applied to the electrode portion 21 of the stage portion 16 from the high frequency power supply portion 14B. Further, the stage unit 16 is cooled by the cooling device 24. The portion of the wafer 2 exposed from the resist mask 3 is removed by the physicochemical action of radicals and ions in the plasma P and removed from the front surface 2a to the back surface 2b, and the wafer 2 is divided into individual chips.

  Ashing is performed after plasma dicing is completed. While introducing an ashing process gas (for example, oxygen gas) from the ashing gas source 18 into the chamber 11, the evacuation mechanism 19 exhausts the gas and maintains the processing chamber 15 at a predetermined pressure. Thereafter, high frequency power is supplied from the high frequency power supply unit 14 </ b> A to the antenna 13 to generate plasma P in the chamber 11 and irradiate the wafer 2 exposed from the window 33 of the cover 31. The resist mask 7 is completely removed from the surface 5 a of the semiconductor wafer 5 by irradiation with the oxygen plasma P.

  After ashing, the drive lots 37A and 37B are driven by the drive mechanism 38 to move the cover 31 from the lowered position to the raised position. Thereafter, the transport carrier 5 is carried out of the chamber 11 by a transport mechanism (not shown).

  During the plasma treatment, the cover 31 is in the lowered position. Therefore, the plasma P is irradiated to the wafer 2 exposed from the window 33 provided in the main body 32 of the cover 31, but the holding sheet 6 and the frame 7 of the transport carrier 5 are covered with the main body 32 of the cover 31. Thus, it is protected without being exposed to the plasma P. Therefore, the etching efficiency of the wafer 2 is not lowered due to the concentration of the plasma P on the frame 7. Further, it is possible to prevent the holding sheet 6 from being deformed or altered by heat due to the action of the plasma P.

  Further, during the plasma processing, a gap δ3 is provided between the lower surface 32b of the main body 32 of the cover 31 at the lowered position and the protective sheet 6, and the protruding portion 34 of the cover 31 that penetrates the opening 8 of the protective sheet 6 is provided. Is not in contact with the protective sheet 6. That is, no part of the cover 31 is in contact with the protective sheet 6. Therefore, the protective sheet 6 is not attached to the cover 31.

  During the plasma treatment, the cover 31 is not in contact with the protective sheet 6 or the ring 7 of the carrier 5 and is in a floating state. If the cover in the floating state is not sufficiently cooled, the radiant heat from the cover 31 to the wafer 2 causes thermal damage to the wafer 2. In the present embodiment, the cover 31 is cooled by heat conduction to the stage unit 16 that is cooled by the cooling device 24. Hereinafter, this point will be described in detail. Since the cover 31 during the plasma processing is in the lowered position, the plurality of protrusions 34 of the cover 31 penetrate the opening 8 of the protective sheet 6, and the end surface 35 a of the heat transfer sheet 35 at the tip 34 a is placed on the stage portion 16. It closely contacts the surface 23 (the upper end surface 21a of the electrode portion 21). Therefore, the heat generated in the main body 32 of the cover 31 by being exposed to the plasma P is transmitted to the stage portion 16 through the protruding portion 34. That is, the protrusion 34 functions as a heat conduction path from the cover 31 to the stage unit 16 by contacting the stage unit 16, thereby effectively cooling the cover 31. Since the cooling is effectively performed by the heat conduction to the stage portion 16 by providing the protruding portion 34, an excessive temperature rise of the main body 32 of the cover 31 during the plasma processing can be suppressed. Radiant heat is effectively suppressed, and thermal damage to the wafer 7 such as resist burning during plasma dicing can be reliably prevented.

  The gap δ4 between the outer peripheral edge of the wafer 2 and the peripheral edge 33a of the window 33 in which the main body 32 of the cover 31 is formed is preferably set as small as possible to prevent the plasma P from being irradiated onto the protective sheet 6. Therefore, particularly in the vicinity of the outer peripheral edge of the wafer 2, the influence of radiant heat from the cover 31 is significant. In the present embodiment, the projecting portion 34 that functions as a heat conduction path to the stage portion 16 is disposed close to the peripheral edge 33 a of the window portion 33, so that the peripheral edge 33 a of the window portion 33 in the main body 32 of the cover 31. The region containing is particularly effectively cooled. As a result, the radiant heat from the cover 31 in the vicinity of the outer peripheral edge of the wafer 2 can be effectively reduced. As described above, in the present embodiment, by disposing the protruding portion 34 in the vicinity of the peripheral edge 33a of the window portion 33, thermal damage to the wafer 2 caused by radiant heat from the cover can be more effectively prevented.

  During the plasma processing, the protruding portion 34 of the cover 31 at the lowered position is arranged point-symmetrically with respect to the center Cw of the wafer 2 (generally coincides with the center Cwi of the window portion 33). That is, the protrusions 34 functioning as a heat conduction path from the cover 31 to the stage unit 16 are uniformly arranged without being biased over the entire outer peripheral edge of the wafer 2. Therefore, the radiant heat from the cover 31 to the wafer 2 can be reduced uniformly over the entire outer periphery of the wafer 2.

  The frame 7 of the carrier 5 during the plasma processing is accommodated in the accommodating groove 36 on the lower surface 32 b of the main body 32 of the cover 31 at the lowered position, and is not in contact with the cover 31. Therefore, direct heat conduction from the frame 7 of the transport carrier 5 to the cover 31 is blocked. Also in this respect, the cover 31 can be more effectively cooled by the heat conduction to the stage portion 16 via the protruding portion 34, and the radiant heat from the cover 31 to the wafer 2 can be more effectively suppressed.

  The present invention is not limited to the above-described embodiment, and various modifications can be made to the present invention as will be exemplified below.

  The shape, size, number, arrangement, and the like of the protruding portion 34 of the cover 31 and the corresponding opening 8 of the holding sheet 6 are not limited to those of the embodiment. For example, as shown in FIG. 7A, a plurality of projections 34 (in this example, curved rectangles) having a relatively large area in plan view are provided at equal angular intervals (in this example, four), and the holding sheet 6 is provided. May be provided with a corresponding opening 8. Further, as shown in FIG. 7B, a plurality (two in this example) of protrusions 34A and 34B are provided in the radial direction of the wafer 2 (inside and outside in the plan view of the main body 32 of the cover 31). May be provided with corresponding openings 8A and 8B.

  As for the material of the cover 31, for example, as shown in FIG. 8, the whole may be a single material (in this example, a carbon material).

  The electrode for electrostatic attraction is not limited to the monopolar type as in the embodiment, but may be a bipolar type.

  The process executed by the dry etching apparatus 1 is not limited to plasma dicing and ashing, and may be, for example, normal dry etching. The dry etching apparatus is not limited to the ICP type as in the embodiment, and may be a parallel plate type. Furthermore, the present invention is not limited to a dry etching apparatus, but can be applied to other plasma processing apparatuses such as a CVD apparatus.

DESCRIPTION OF SYMBOLS 1 Dry etching apparatus 2 Wafer 2a Front surface 2b Back surface 3 Resist mask 5 Conveyance carrier 6 Holding sheet 6a Adhesive surface 6b Non-adhesive surface 6c Circular region 6d Annular region 7 Frame 8, 8A, 8B Opening 11 Chamber 11a Gas inlet 11b Exhaust port DESCRIPTION OF SYMBOLS 12 Dielectric wall 13 Antenna 14A, 14B High frequency power supply 16 Stage part 17 Process gas source 18 Ashing gas source 19 Decompression mechanism 21 Electrode part 21a Upper end surface 21b Refrigerant flow path 22 Exterior part 22a Upper end surface 23 Mounting surface 24 Cooling device 25 Refrigerant Circulating device 26 Electrostatic adsorption electrode 27 DC power source 31 Cover 32 Main body 32a Upper surface 32b Lower surface 32c Tapered depression 33 Window portion 33a Peripheral 34 Projection portion 34a Front end 35 Heat transfer sheet 35a End surface 36 Housing concave groove 36a Bottom wall 36b, 36c Side wall 37 A, 37B Drive rod 38 Drive mechanism 40 Control device

Claims (8)

A depressurizable chamber;
A plasma source for generating plasma in the chamber;
A holding sheet that holds the substrate, a frame to which the holding sheet is attached, and an opening provided so as to penetrate in a thickness direction at a position between the substrate and the frame of the holding sheet, A transport carrier that can be carried into and out of the chamber;
A stage provided in the chamber and on which the carrier is placed;
A main body for covering the holding sheet and the frame, a window formed to penetrate the main body in the thickness direction, and a protrusion corresponding to the opening of the holding sheet protruding from the main body. A cover to provide,
A first position that allows the transport carrier to be loaded and unloaded from the stage away from the stage; the main body covers the holding sheet and the frame of the transport carrier placed on the stage; and the window portion. A cover driving mechanism that exposes the substrate held by the holding sheet and moves the cover to a second position where the protruding portion extends to the stage through the opening of the holding sheet and contacts the stage. And a plasma processing apparatus.   The plasma processing apparatus of Claim 1 provided with the cooling device of the said stage which has the refrigerant | coolant flow path formed in the said stage, and the refrigerant | coolant circulation apparatus which circulates a refrigerant | coolant in the said refrigerant | coolant flow path.   The plasma processing apparatus according to claim 1, wherein the protruding portion is disposed in proximity to a peripheral edge of the window portion.   The plasma processing apparatus of Claim 3 with which the shortest distance of the said protrusion part and the periphery of the said window part is set to the range of 3 mm or more and 20 mm or less.   5. The plasma processing apparatus according to claim 1, wherein the protrusion and the opening are arranged point-symmetrically with respect to the center of the substrate. 6.   The plasma processing apparatus according to claim 1, wherein the main body of the cover includes a concave portion that accommodates the frame of the transport carrier at the second position. A holding sheet for holding the substrate;
A frame to which the holding sheet is attached;
A part of the cover that covers the holding sheet and the frame passes through the plasma during the plasma processing of the substrate, and is provided so as to penetrate in a thickness direction at a position between the substrate and the frame of the holding sheet. An opening that extends to and contacts the stage of the processing apparatus. Preparing a conveyance carrier comprising a holding sheet, a frame to which the holding sheet is attached, and an opening provided to penetrate the holding sheet in the thickness direction;
Holding the substrate on the holding sheet of the carrier,
Carrying the carrier into the chamber of the plasma processing apparatus and placing it on the stage;
A cover is positioned at a predetermined position with respect to the stage, the holding sheet and the frame of the transport carrier are covered with the main body of the cover, the substrate is exposed by a window provided in the main body, and protrudes from the main body A projecting portion that penetrates through the opening of the holding sheet and contacts the stage,
A plasma processing method, wherein plasma is generated in the chamber to perform plasma processing on the substrate exposed from the window.

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