Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B53/00—Devices or means for dressing or conditioning abrasive surfaces
  • B24B53/017—Devices or means for dressing, cleaning or otherwise conditioning lapping tools
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B49/00—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
  • B24B49/12—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation involving optical means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B49/00—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
  • B24B49/18—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation taking regard of the presence of dressing tools
  • B24B49/186—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation taking regard of the presence of dressing tools taking regard of the wear of the dressing tools

Definitions

• the present invention relates to a polishing technique, and particularly to a polishing pad life determining method, a conditioner life determining method, a conditioner quality determining method, a polishing pad conditioning method, a polishing apparatus, a semiconductor device, and a semiconductor device manufacturing method. Things. Background art
• polishing apparatus for example, chemical mechanical polishing (Chemical mechanical polishing) for global flattening of a surface of a semiconductor device wafer or the like.
• CMP is a process of removing the surface irregularities of a wafer by using chemical polishing (melting with a polishing agent or a solution) in combination with physical polishing. Polishing is performed by pressing the wafer surface with the pad and causing relative movement, thereby enabling uniform polishing within the wafer surface. In such a polisher, the polished surface of the polishing pad is clogged and deteriorates according to the polishing time. Therefore, regular conditioning (also referred to as dressing) is performed and good processing is continued. Like a maintainer Is performed.
• This conditioning is performed by bringing the polishing surface of the polishing pad into contact with the conditioning surface of a conditioner (also referred to as a conditioning tool or a dressing tool) and moving the polishing pad and the conditioner relative to each other.
• a conditioner also referred to as a conditioning tool or a dressing tool
• the conditioner for example, a tool in which abrasive grains such as diamond particles are distributed over the entire annular or disk-shaped conditioning surface is used.
• the relative movement is performed, for example, by rotating both the polishing pad and the conditioner.
• the thickness of the polishing pad is determined by the consumption caused by the polishing of the object to be polished such as a wafer and the consumption caused by the conditioning ( As a result of cutting, the desired polishing characteristics cannot be obtained over time, and the service life is exhausted.
• a conditioning device that performs the conditioning generally includes the conditioner and a holding unit that holds the conditioner.
• the conditioning surface of the conditioner is also consumed due to the conditioning of the polishing pad, so that the desired conditioning characteristics cannot be obtained before long, and the life is over. Therefore, conventionally, the life of the conditioner was determined based on the accumulated time and the number of times of conditioning by the conditioner, and when it was determined that the life had expired, the conditioner was replaced with a new one. And a new con Conditioners always have the desired conditioning characteristics and can be used for conditioning polishing pads without special checks.
• conditioning of a polishing pad was performed every time a predetermined number of objects to be polished were polished by the polishing pad. However, conditioning was performed each time under the same conditioning conditions.
• the life of the polishing pad was determined based on the accumulated time and the number of times of polishing and conditioning, so that the life of the polishing pad could not be accurately determined. . For this reason, in actuality, it is determined that the life of the polishing pad has expired fairly early, despite the fact that the desired polishing characteristics are still sufficiently obtained in anticipation of a considerable margin, and a new polishing pad is determined. Had been replaced by Due to the force s, the running cost of the polishing apparatus was increased. If it is not determined that the life of the polishing pad has expired early with sufficient allowance, the life of the polishing pad cannot be accurately determined. Although the characteristics are no longer obtained, the object to be polished is polished, and the object to be polished cannot be accurately polished, resulting in a fatal result.
• the life of the conditioner is determined based on the accumulated time and the number of times of conditioning. Therefore, the life of the conditioner cannot be accurately determined. For this reason, in practice, a considerable margin is taken into consideration, and although the desired conditioning characteristics can be obtained in real time, it is determined that the life of the conditioner has expired quite early, and the new conditioner is determined. It had been replaced with a conditioner. Therefore, the running cost of the polishing apparatus has increased. Note that the life of the conditioner is If the conditioner is not determined, the life of the conditioner cannot be accurately determined, and the polishing pad may be conditioned even though the conditioner has not obtained the desired conditioning characteristics. As a result, the polishing pad cannot exhibit desired polishing characteristics, and as a result, the object to be polished cannot be accurately polished, resulting in a fatal result.
• new conditioners do not always have the desired conditioning properties. For example, in the case of a new conditioner, the cutting ability of the abrasive grains is too high, and the polishing surface of the polishing pad becomes too rough beyond the stage of recovering from clogging of the polishing pad. It has been found that the polished pad may not be able to exhibit desired polishing characteristics in some cases. Therefore, if a new conditioner is used for conditioning the polishing pad without any check as in the conventional case, the polishing pad cannot exhibit desired polishing characteristics, and the object to be polished can be precisely formed. They could not be polished and could have fatal consequences. However, there has been no effective method for judging the quality of a new conditioner.
• conditioning of the polishing pad has been performed every time a predetermined number of objects to be polished are polished by the polishing pad, as described above.
• the conditioning is performed each time under the same conditioning conditions.
• the conditioning surface of the conditioner gradually wears out, the condition of the polishing surface of the polishing pad after conditioning gradually changes. Therefore, the polishing state of the object to be polished by the polishing pad changes for each object to be polished, which is not preferable. Disclosure of the invention
• the present invention has been made in view of such circumstances, and has as its object to provide a polishing pad life determining method capable of accurately determining the life of a polishing pad.
• Another object of the present invention is to provide a conditioner life determining method capable of accurately determining the life of a conditioner.
• Still another object of the present invention is to provide a conditioner quality judgment method capable of appropriately judging the quality of a new conditioner. Furthermore, the present invention is to polish each object to be polished in the same manner. It is an object of the present invention to provide a polishing pad conditioning method that can perform the polishing.
• Another object of the present invention is to provide a polishing apparatus that can reduce running costs.
• Still another object of the present invention is to provide a polishing apparatus that can polish each object to be polished in the same manner.
• Still another object of the present invention is to provide a semiconductor device manufacturing method capable of manufacturing a semiconductor device at low cost as compared with a conventional semiconductor device manufacturing method, and a low-cost semiconductor device. .
• a first invention for achieving the above object is a conditioning method for conditioning a polishing pad used for polishing an object to be polished with a conditioner
• the thickness of the polishing pad is measured
• the one or more conditioning of the polishing pad is performed.
• a conditioning condition at the time of the next conditioning after the one or more conditionings is set, and the next conditioning is performed according to the set conditioning condition. Is what you do.
• a second invention for achieving the above object is the first invention, wherein the conditioning condition is a conditioning time.
• a third invention for achieving the above object is a life determining method for determining the life of a conditioner used for conditioning a polishing pad used for polishing an object to be polished,
• the thickness of the polishing pad is measured.
• a fourth invention for achieving the above object is:
• the new conditioner is determined to be defective.
• a fifth invention for achieving the above object is a life determining method for determining the life of a polishing pad used for polishing an object to be polished, the method comprising measuring the thickness of the polishing pad, and measuring the thickness of the polishing pad. When the thickness of the polishing pad is smaller than a predetermined value, it is determined that the life of the polishing pad has expired.
• the polishing pad is relatively moved while applying a load between the polishing pad and the object to be polished.
• an alarm is generated to notify that the polishing pad should be replaced with a new polishing pad, or the polishing pad is automatically turned off.
• the polishing pad is relatively moved while applying a load between the polishing pad and the object to be polished.
• a conditioning unit having a conditioner for conditioning the polishing pad with the conditioner
• the polishing pad is used for a first evening and a second evening thereafter.
• a calculating unit for calculating an average cutting rate during a cumulative conditioning time of the polishing pad by a conditioner; and an alarm indicating that the conditioner should be replaced with a new conditioner when the average cutting rate is lower than a predetermined value. Or means for automatically replacing the conditioner with a new conditioner.
• the polishing pad is relatively moved while applying a load between the polishing pad and the object to be polished.
• a conditioning unit having a conditioner for conditioning the polishing pad with the conditioner
• Means for generating an alarm or automatically replacing said conditioner with a new conditioner When,
• the polishing pad is relatively moved while applying a load between the polishing pad and the object to be polished.
• a conditioning unit having a conditioner for conditioning the polishing pad with the conditioner
• Means for determining an average cutting rate during a cumulative conditioning time of the polishing pad by the conditioner Based on the thickness measured at the first evening timing and the thickness measured at the second evening timing, within a period from the first timing to the second timing, Means for determining an average cutting rate during a cumulative conditioning time of the polishing pad by the conditioner;
• a conditioning condition setting unit that sets a conditioning condition of a next conditioning after the period of the polishing pad based on the average cutting rate
• a tenth invention for achieving the above object is the ninth invention, wherein the conditioning condition is a conditioning time.
• the eleventh invention for achieving the above object is characterized in that the polishing pad and the object to be polished are relatively moved while applying a load between the polishing pad and the object to be polished.
• a conditioning unit having a conditioner, wherein the conditioning unit performs conditioning each time the polishing pad polishes a predetermined number of the objects to be polished;
• a measuring unit for measuring the thickness of the polishing pad at a first evening and at a second timing thereafter;
• the workpiece to be polished by the polishing pad and the source after the second timing is based on the thickness measured at the second evening timing.
• a twelfth invention for achieving the above object has a step of flattening a surface of a semiconductor wafer by using the polishing apparatus according to any one of the sixth invention to the eleventh invention.
• a thirteenth invention for achieving the above object is a semiconductor device characterized by being manufactured by the method for manufacturing a semiconductor device according to the first invention.
• FIG. 1 is a schematic top view schematically showing a polishing apparatus according to the first embodiment of the present invention.
• FIG. 2 is a schematic top view showing a state of processing a wafer by the polishing apparatus shown in FIG.
• FIG. 3 is a schematic cross-sectional view schematically showing main elements located on a first polishing stage in the polishing apparatus shown in FIG. 1 when viewed from the side.
• FIG. 4 is a schematic flowchart showing the operation of the polishing apparatus shown in FIG.
• FIG. 5 is another schematic flowchart showing the operation of the polishing apparatus shown in FIG.
• FIG. 6 is a flowchart showing a semiconductor device manufacturing process. BEST MODE FOR CARRYING OUT THE INVENTION
• FIG. 1 is a schematic top view schematically showing a polishing apparatus 1 according to a first embodiment of the present invention.
• FIG. 2 is a schematic top view showing an aspect of wafer processing of the polishing apparatus 1 shown in FIG.
• FIG. 3 is a schematic cross-sectional view schematically showing main elements located on the first polishing stage in the polishing apparatus 1 shown in FIG. 1 when viewed from the side.
• a polishing state monitoring device 50a which will be described later, is omitted for convenience of notation.
• the polishing apparatus 1 is an example of a CMP apparatus that precisely and flatly polishes a semiconductor wafer as an object to be polished in a three-stage polishing process.
• the polishing apparatus 1 is mainly composed of a cassette index section 100, a wafer cleaning section 200, and a polishing section 300, and each section is individually partitioned.
• a clean chamber is configured.
• an automatic opening / closing shut-down may be provided between each room.
• the cassette index section 100 includes a wafer mounting table 120 on which cassettes (also referred to as carriers) holding a plurality of wafers C1 to C4 are mounted and an unprocessed wafer taken out of the cassette.
• Cleaning unit 200 Cleaning unit 200
• the first transfer robot 150 that carries the wafers that have been washed in the wafer cleaning unit 200 after polishing into the temporary storage table 211 and stores them in a cassette. Is configured.
• the first transfer robot 150 has two articulated arms 15 3 a and 15 3 b.
• the robot is a multi-joint arm type robot having a base 151, a swivel base 152 that can be horizontally rotated and raised and lowered on this base 151, and two multi-joint robots mounted on a swivel table 152.
• One arm 15 3 a, 15 3 b, each articulated arm 15 3 a, 1 53 a 1 and 5b (the B-arm 155b is offsetly disposed below the A-arm 155a, and is vertically overlapped in FIGS. 1 and 2).
• a holding portion for mounting and holding the wafer by suction is formed at the distal ends of the A-arm 155a and the B-arm 155b.
• the base 151 is provided with a linear moving device that is horizontally movable along a linear guide 160 provided on the floor surface.
• the first transfer robot 150 moves in front of the target cassette along the linear guide 160, and horizontally turns and raises and lowers the swivel base 152 to operate the A-arm 150a or B Move the arm 155b to the desired slot height and operate the articulated arm 153a and the A-arm 155a, or the articulated arm 153b and the B-arm 155b.
• the unprocessed wafer in the target slot can be sucked and held and taken out by the holding part at the tip of the A arm 155a or the B arm 155b, or the processed wafer can be stored in the target slot. .
• the wafer cleaning section 200 includes the first cleaning chamber 210, the second cleaning chamber 220, and the third cleaning chamber 220.
• the polishing chamber 230 is configured to perform a drying process under a nitrogen atmosphere.
• the unprocessed wafer before polishing passes through the wafer cleaning section 200 from the cassette index section 100 through the cleaning machine temporary storage table 211 without going through the above-mentioned cleaning step, and passes through the wafer polishing section 3. 0 Carried in 0.
• the polishing unit 300 is divided into four parts, and is indexed according to the positioning stop positions of the index table 340 and the index table 340 which are rotated and fed every 90 degrees by the operation of a stepping motor or the like. Unprocessed wafers are loaded into the first polishing stage 310, the second polishing stage 320, the third polishing stage 330, and the index table 340 provided so as to surround the index table 340 from the outer periphery. It is composed of a transfer stage 350 for unloading processed wafers.
• the polishing stage may be called a polishing zone or a polishing chamber.
• each section of the index table 340 divided into four chucks V1 to V4 for holding the wafer by suction from the back surface are arranged exposed on the table upper surface, and each of the chucks VI to V4 is indexed.
• the table 340 is rotatably supported in a horizontal plane (a plane parallel to the paper surface in FIG. 1), and the electric motor and air motor provided inside the index table 340 are provided. High-speed rotation and stop holding are freely mounted by driving means such as overnight.
• the diameter of the chucks V1 to V4 is slightly smaller than the diameter of the wafer. It is formed to have a small diameter, and is configured to be able to grip the outer peripheral end of the wafer held by the chucks V1 to V4.
• the three polishing stages of the first polishing stage 310, the second polishing stage 320, and the third polishing stage 330 are respectively capable of swinging in the horizontal direction relative to the index table 340.
• a polishing arm 3 11 1, 3 2 1, 3 3 1 that can move up and down in the vertical direction is provided.
• a polishing head 311a which is suspended from the polishing arm 311 and is rotatable at high speed in a horizontal plane, is attached to a tip of the polishing arm 311.
• the lower end surface has a polishing pad 311c as a polishing body for polishing the wafer flat by relative rotation with respect to the wafer.
• the polishing pad 311c is mounted on the mounting plate 311b, and the mounting plate 311b is held on the polishing head 311a by vacuum suction.
• the pad 311c is automatically replaced together with the support member 311b by a pad exchange device 318 described later.
• a polishing head 311a and a pad exchange device 318 for example, the one disclosed in Japanese Patent Application Laid-Open No. 2001-148369 may be used. it can.
• the tip of each of the polishing arms 3 2 1, 3 3 1 is also suspended from the polishing arms 3 2, 3 3 1 and is a polishing head that can rotate at high speed in a horizontal plane.
• a polishing pad is provided at its lower end surface as a polishing body for flatly polishing the wafer by relative rotation with the wafer.
• each of the polishing stages 310, 320, and 330 has a pad thickness measuring device 319, 329, which measures the thickness of the polishing pad. 339, a pad conditioning device for conditioning and polishing the surface of the polishing pad, 317, 327, 3337, and a pad exchange device for automatically exchanging the polishing node 318, 3 2 8 and 3 3 8 are attached.
• a commercially available contact stylus type displacement meter is used, and the stylus 3 19 a contacts the polishing surface of the polishing pad 3 11 c and moves up and down according to its height.
• the thickness distribution of the polishing pad 311c in the radial direction can be measured.
• the average value of the thickness distribution in the radial direction (the maximum value or the minimum value may be used) is adopted as the thickness of the polishing pad 311c.
• the thickness distribution of c in the radial direction is measured, for example, the thickness of only one point on the polished surface of the polishing pad 311 c may be measured.
• an optical displacement meter may be used instead of the contact stylus displacement meter.
• the node thickness measuring devices 329 and 339 have the same configuration as the node thickness measuring device 319.
• the pad conditioning device 3 17 has a conditioner 3 1 1 having a ring-shaped conditioning surface 3 1 7 a on which ring-shaped diamond abrasive grains and the like are distributed. 7b, a conditioner holding member 317c for holding the conditioner 317b, and a rotating mechanism 317d for rotating the conditioner holding member 317c.
• the polishing surface of the polishing pad 311c is brought into contact with the conditioning surface 317a of the conditioner 317b to apply a load, and the polishing pad 311 is rotated by each rotation.
• the polished surface of c is conditioned.
• the node conditioning devices 327 and 3337 have the same configuration as the pad conditioning device 317.
• the conditioners of the pad conditioning devices 3 17, 3 2 7, 3 3 7 are designed so that the workers can replace them manually, but as in the case of the polishing pad.
• a conditioner exchange device for automatically exchanging conditioners may be provided.
• Polishing arms and chucks at each polishing stage 310, 320, 330 The relative position of the polishing head, the pad thickness measuring device, the pad conditioning device, and the pad exchanging device is defined so as to be located on the rotating circumference of the polishing head at the tip of the polishing arm. For this reason, for example, when performing polishing in the first polishing stage 310, the polishing arm 311 is swung to move the polishing head onto the chuck V4, and the polishing head and the chuck V4 are moved. The polishing pad 3 is pressed against the wafer by lowering the polishing arm 311 while rotating the polishing pad 4 relatively, thereby performing polishing.
• an abrasive slurry
• a water supply device not shown
• drainage is performed by, for example, rotating a chuck.
• the index table 3400 can be rotated.
• the polishing arm 311 is swung at a predetermined timing to be described later, and the thickness of the polishing pad is measured by the pad thickness measuring device 319.
• the polishing arm 311 is further rocked (for each number of sheets), and the pad conditioning device 317 performs conditioning (conditioning) to correct clogging and irregularity of the polishing pad 311c.
• the polishing arm 311 is further moved to move the polishing pad 311c upward to the pad exchange device 3188, and the polishing pad 311c is moved by this device. Perform automatic replacement.
• An arm position detector (not shown) for detecting the swing angle position of the arm is attached to the polishing arm 311.
• the polishing processing position of the polishing arm 311 ⁇ pad thickness measurement position ⁇ conditioning position
• the pad replacement position is detected.
• each polishing stage has a wafer being polished.
• a polishing state monitoring device 50a for optically monitoring the polishing state of the wafer is attached, and it is possible to detect a decrease in the film thickness during the polishing processing in real time.
• the polishing state monitoring device 500a for example, the device disclosed in Japanese Patent Application Laid-Open No. 2000-480680 can be used.
• the polishing state monitoring device 50a has an arm 61 that extends approximately parallel to the polishing arm of each polishing stage and is freely movable in the horizontal direction.
• An optical fiber, etc., is built in, and the tip of the arm 61 irradiates the probe light locally on the wafer being polished while being held by the chuck, and receives the reflected light from the wafer and guides it to a predetermined location. It is supposed to be done.
• the arm 61 is configured to be synchronized with the polishing arm during polishing in order to avoid mechanical interference with the polishing arm.
• the polishing state monitoring device 50a monitors the polishing state based on the reflected light from the wafer obtained when the tip of the arm 61 is positioned on the wafer.
• the second transfer robot 360 is a multi-joint arm type robot similar to the first transfer robot 150 described above, and can be swung on a swivel base 36 2 capable of horizontal rotation and up / down movement.
• the two articulated arms 3663a and 3663b attached to the arm, and the A-arms 3655a and It consists of B-arm 365 b.
• the A arm 365a and the B arm 365b are offset vertically and arranged, and a wafer is placed and held at the tip of both arms 365a and 365b.
• the holding part is formed.
• the third transfer robot 370 includes a swing arm 371 that can swing horizontally and vertically in relation to the index table 340, and a swing arm at the tip of the swing arm 371.
• 37 A and B clamps 375 b and 375 b which are suspended at both ends of a pivot arm 372 and a pivot arm 3 72, which are attached so as to be able to pivot horizontally with respect to 1. It is configured.
• the A clamp 375a and the B clamp 375b are disposed at the ends of the pivot arm at the same distance from the pivot center of the pivot arm 372.
• the state shown in FIG. 1 shows the standby posture of the third transfer robot 370, and unprocessed wafers are placed below the A clamp 375a and the B clamp 375b in the figure.
• a temporary placing table 381 for placing a polished wafer and a B temporary placing table 382 for placing a polished wafer are provided.
• the swing arm 371 of the third transfer robot 370 is swung, and the swing arm 372 is swung, so that the A-clamp 375 a or the B-clamp 375 b is turned into a chuck of the index table 340.
• V1 can be moved to the position above, and the swing arm 371 is lowered at that position, and the wafer on the chuck is clamped and received by the A clamp 375a or the B clamp 375b, or the wafer is placed on the chuck. A new wafer can be placed and held.
• an arm and a clamp for loading the wafer before polishing and an arm and a clamp for discharging the polished wafer are used.
• the upper A arm 365 a is the arm for loading unprocessed wafers
• the lower B arm 365 5 b is defined as the unloading arm
• a clamp 375a is defined as the loading clamp
• B clamp 375b is defined as the unloading clamp.
• the operations relating to pad thickness measurement, pad exchange, conditioning, and conditioner exchange will be omitted, and the operation of the polishing apparatus 1 will be described.
• the operations related to pad thickness measurement, pad replacement, conditioning, and conditioner replacement will be described in detail later with reference to a flowchart, focusing on one polishing stage.
• the wafer before polishing by the polishing apparatus 1 (referred to as an unprocessed wafer in this specification) is referred to as a first polishing P1, a second polishing P2, and a third polishing P3.
• An example will be described in which polishing is performed flat by the three-stage CMP process.
• the first polishing process Pl, the second polishing process P2, and the third polishing process P3 are a first polishing stage 310, a second polishing stage 320, a third polishing stage. It's done at 330.
• the polishing process is temporarily terminated.
• the primary polishing P 1 is a preceding polishing of the secondary polishing P 2, and it is not necessary to detect the end point. And the polishing is terminated, and the polishing is terminated in a predetermined polishing time tp 1.
• the unprocessed wafer Wd set in the cassette C1 of the force set index unit 100 is sequentially polished by the polishing unit 300 to become a processed wafer Wp.
• a dotted line and an arrow indicate the flow of the wafer from the cleaning process in the wafer cleaning unit 200 to the storage in the cassette C4 of the cassette index unit 100.
• Each transport robot 150, 360, 370, index table 340, chucks V1 to V4, polishing arm 311, 321, 331, polishing The operation of the head etc. is not shown
• the control unit is controlled by a control unit composed of a computer or the like. The control unit controls these operations based on a preset control program.
• the polishing apparatus 1 also includes an alarm unit for issuing an alarm described later, and an input device for the operator to give various commands and the like.
• the alarm unit may generate one of a visual alarm and an audible alarm, or may generate both of them.
• the first transfer robot 150 moves to the position of the cassette C1, and the swivel table 152 is horizontally turned and moved up and down. Move the B-arm 155b to the target wafer slot height, extend the articulated arm 155b and the B-arm 155b, and hold the tip of the B-arm 155b at the tip. Hold the unprocessed wafer W d in the slot by suction and pull out both arms by reducing the length. Then, the revolving table 15 2 is rotated by 180 degrees toward the wafer cleaning unit 200, and the unprocessed wafer W d is placed on the cleaning machine temporary placing table 2 1 1 provided in the cleaning unit 200. Is placed.
• the second transfer robot 360 of the carry-in stage 350 facing the wafer cleaning chamber 200 is rotated by the turntable 36 when the unprocessed wafer W d is placed on the temporary support table 211. Activate 2 to rotate the A arm 3 6 5 a so that the tip end faces the temporary washing machine stand 2 1 1 and extend the multi-joint arm 3 6 3 a and the A arm 3 6 5 a.
• the unprocessed wafer W d on the temporary washing machine stand 2 1 1 is held by suction at the holding section at the tip of the A arm.
• the articulated arm 36 3 a and the A arm 365 5 a are reduced in length, and the swivel table 36 2 is rotated to invert, and the multi-joint arm 36 65
• the unprocessed wafer Wd is placed on the A temporary placing table 381, by extending the joint arm 363a and the A arm 365a.
• the third transfer port The boat 370 moves down and grips the unprocessed wafer Wd with the A clamp 375a, and waits until the index table 340 has been positioned at the standby position where the gripping operation has been performed to the predetermined height after gripping. Yes (standby posture).
• the index table 340 stops positioning the swinging arm 371 and the rotating arm 372 are oscillated and rotated so that the unprocessed wafer is placed on the chuck V1 and held by suction.
• the third transfer robot 370 is lifted after the clamp is released, and the swing arm 371 and the rotation arm 372 are oscillated and rotated so that the next unprocessed wafer W d is clamped by the A clamp 3. 7 Hold by 5a and wait for the next index operation at the standby position at the specified height.
• polishing in the polishing section 300 is started. Until the unprocessed wafer Wd carried into the carry-in stage 350 is carried out of the transfer stage 350 through the first polishing stage 310, the second polishing stage 320, and the third polishing stage 330. Is as follows.
• the index table 340 is moved to the position shown in FIGS. Rotate 90 degrees clockwise in the middle to position the unprocessed wafer W d on the first polishing stage 310 (V 4 position in FIGS. 1 and 2).
• the polishing arm 3 1 1 is swung to move the polishing head onto the unprocessed wafer Wd, and ⁇
• the polishing head and the chuck V1 are rotated at a high speed, for example, in opposite directions, and the polishing arm 311 is lowered to remove the polishing pad at the lower end of the polishing head to the wafer. Pressed upward to perform primary polishing P1.
• the polishing arm 311 is moved in a minute range so that the polishing pad reciprocates between the center of rotation of the wafer and the outer peripheral edge while supplying slurry from the axis of the polishing head.
• the wafer is moved and polished uniformly and flat.
• a new unprocessed wafer is loaded onto the chuck V2 by the third transfer robot 370 during the first polishing.
• the primary polishing process P 1 in the first polishing stage 310 is time control as described above. After a predetermined polishing time tp 1 has elapsed, the polishing arm 3 1 1 is raised to perform the first polishing. Stop polishing at stage 310. After that, the control unit determines whether or not the operation of the index table 340 is possible (that is, whether or not the operation of the stage other than the first polishing stage 310 is completed). If not, wait for it to be possible.
• the index table 340 is rotated 90 degrees clockwise again, and the wafer on which the first polishing process P 1 has been completed is moved to the second polishing stage 3. Position it at 20 (V3 position in Figs. 1 and 2). At this time, simultaneously, the polishing arm 3221 is swung to move the polishing head onto the wafer. Then, the polishing arm 3 21 is lowered, and the polishing (second polishing P 2) on the second polishing stage 3 20 is performed by the same operation as the primary polishing P 1.
• the second polishing process P2 at the second polishing stage 320 is a so-called final inspection process.
• the polishing arm 3221 is raised and 2 Polishing stage 3 2 0 Stop the polishing process, and wash and drain the abrasive (slurry) on the workpiece.
• control unit determines whether or not the operation of the index table 340 is possible (that is, whether or not the operation at a stage other than the second polishing stage 320 is completed). If not, wait for it to be possible.
• the index table 340 is rotated 90 degrees clockwise again, and the wafer after the second polishing P 2 is polished for the third time. Position the stage 330 (V2 position in the figure). Then, the polishing arm 331 is moved down to perform the polishing (third polishing P3) on the third polishing stage 330 by the same operation as described above.
• the third polishing process P3 at the third polishing stage 330 is also a so-called end point detection process, like the second polishing process P2.
• the control unit controls the polishing arm. 3 3 1 is raised to stop the polishing in the third polishing stage 330.
• control unit determines whether or not the operation of the index table 340 is possible (that is, whether or not the operation in a stage other than the third polishing stage 330 is completed), and If not, wait until it becomes possible.
• the index table 340 is rotated 90 degrees clockwise again, and the wafer after the third polishing P 3 is transferred to the transfer stage 350. (Position V1 in Figs. 1 and 2).
• the third transfer robot 370 operates the swing arm 371 and the rotation arm 372 in the ⁇ operation and the rotation operation to finish the polishing process.
• the wafer W p is unloaded and the next unprocessed wafer W d is loaded on the chuck V 1.
• the above operation is repeated by chucking and holding the chuck V1.
• the second transfer robot 360 is turned on the swivel table 36 2 and the articulated arm.
• 3 6 3 b and the B arm 3 6 5 b are operated to hold the processed wafer W p on the B temporary placing table 3 8 2 with the holding section at the tip of the B arm, and the swivel table 3 62 is swiveled.
• the multi-joint arm 365 3 b and the B arm 365 5 b are extended and operated, and the processed wafer Wp is placed at the washing machine entrance 2 16 of the washing section 200.
• the first cleaning chamber 210 performs double-sided cleaning using a rotating brush
• the second cleaning chamber 220 performs surface pencil cleaning under ultrasonic vibration
• the third cleaning chamber 230 uses pure water.
• a drying process in a drying chamber 240 under a nitrogen atmosphere is taken out of the cleaning section 200 by the A arm 155a of the first transport robot 150 in the cassette index section 100, and the cassette C4 Stored in the designated slot.
• the unprocessed wafer Wd set in the cassette C1 of the cassette index section 100 is sequentially polished by the polishing section 300 to become a processed wafer Wp, and the wafer cleaning section
• the flow of the wafer from the cleaning process at 200 until the cassette is stored in the cassette C4 of the cassette index unit 100 has been described.
• the control unit automatically controls a plurality of wafers (for example, a plurality of wafers contained in the cassette C1) from an operator via an input device (not shown).
• a command is issued to start continuous polishing (herein referred to as “series polishing”), basically, for each of these wafers, the operations for different wafers are performed simultaneously in each stage at the same time. While following the wafer flow described above. Is performed.
• FIG. 1 The operation of the polishing apparatus 1 will be described with reference to flow charts shown in FIGS. See also Figure 1 to Figure 3.
• the control unit first determines whether or not the series polishing start command has been obtained from the input device (step Sl). If the start command has not been obtained, the control unit waits until it is obtained. This directive specifies how many wafers are polished continuously. Here, it is assumed that N wafers are specified to be continuously polished.
• the control unit swings the polishing arm 311 to move the polishing head 311a to a position above the pad thickness measuring device 319, and the pad thickness is increased.
• the measuring device 319 is caused to measure the thickness of the polishing pad 311c (step S2).
• the value of the thickness may be any of the average value, the maximum value, the minimum value, and the value of a certain point in the radial thickness distribution, but the average value is preferable.
• control unit determines whether or not the pad thickness measured in step S2 is equal to or greater than a predetermined minimum control value d1 that determines the life of the polishing pad 311c. Then, it is determined whether or not the life of the polishing pad 311c has expired (step S3).
• step S2 the minimum control value is d1 or more (that is, polishing pad 3 If it is determined that the life of 11c has not expired, the flow shifts to step S11 described later. On the other hand, when it is determined in step S2 that the thickness is thinner than the minimum control value d1 (that is, the life of the polishing pad 311c has expired), the process proceeds to step S4. In this case, the wafer is not actually polished.
• step S the control unit swings the polishing arm 311 to move the polishing head 311a upward to the pad exchange device 318, and the polishing pad 3 Replace 3 1 1 c with a new polishing pad. After that, the control unit causes the pad thickness measuring device 319 to measure the thickness of the polishing pad 311c as in step S2 (step S5).
• the control unit moves the polishing head 311a by moving the polishing arm 311 above the pad conditioning device 3117, and lowers the polishing head 311a.
• the polishing head 311a and the conditioner holding member 317c are rotated relative to each other to perform break-in conditioning of the polishing pad 311c (step S6).
• Pre-quin conditioning is conditioning that is usually performed on a new polishing pad, and for example, the conditioning time is lower than in the case of normal conditioning (conditioning performed in steps S12 and S14). And the cutting amount of the polishing pad 311c by the conditioner 317b is relatively large.
• step S2 the control unit causes the pad thickness measuring device 319 to measure the thickness of the polishing pad 311c (step S7). Thereafter, the control unit divides the difference between the pad thickness measured in step S7 and the pad thickness measured in step S5 by the conditioning time of the break-in conditioning in step S6. The average cutting rate of the polishing pad 311c in step S6 is calculated (step S8). After that, the control unit determines that the average cutting rate calculated in step S8 is It is determined whether or not the life of the conditioner 317 b has expired by determining whether or not the life of the conditioner 317 b is equal to or more than a minimum control value R1 for determining the life of the conditioner 317 b (step S9).
• step S9 If it is determined in step S9 that the value is equal to or more than the minimum control value R1 (that is, the life of the conditioner 317b has not expired), the next series of polishing (steps S12, S14 described later)
• step S8 the conditioning time (one time) at which the cutting amount of the polishing pad 311c by each conditioning of the polishing pad 311c performed in step 1) becomes a predetermined value is determined.
• the conditioning time is obtained from the calculated average cutting rate, and this conditioning time is reset in the internal memory of the control unit as the conditioning time in the conditioning in the next series of polishing (step S10). Then, the process returns to step S1.
• step S11 the control unit estimates the thickness of the polishing pad 311c after polishing the number (N) of wafers specified in step S1.
• steps S12 and S14 which will be described later, the number of wafers to be conditioned once is determined in advance, for example, conditioning is performed once for polishing two wafers. Therefore, it is possible to calculate how many conditionings have been performed after polishing N wafers. Then, the number of times of conditioning, the currently set conditioning time (conditioning time set latest by steps S10, S19, S30) and the average cutting rate (step S 8, S 1 8 3
• the polishing pad after polishing N wafers in step S 1 by multiplying the average of the average cutting rates obtained in S 28 by A predicted value of 311c thickness can be obtained.
• the control unit calculates the polishing pad 311c predicted in step S11. It is determined whether the thickness is equal to or greater than the minimum management value d1. If the thickness of the polishing pad 311c predicted in step S11 is equal to or greater than the minimum control value d1, the life of the polishing pad 311c will expire even if N wafers are polished. If not, proceed to step S12.
• step S11 the control unit sets the maximum value of the number of polishing pads 311c that is predicted when it is assumed that a certain number of wafers have been polished that the thickness of the polishing pad 311c does not become thinner than the minimum management value d1. Find M.
• the maximum value M is calculated under the condition of M ⁇ N in the same manner as the calculation for the N wafers in step S11, by calculating the predicted value of the polishing pad 311c for each wafer, It can be obtained by comparing with the value d 1. Then, the control unit resets the number of wafers to be actually polished in the continuous polishing from the number of wafers specified in step S1 to the number of M wafers (step S13), and proceeds to step S14. Transition. In step S12, the control unit causes each unit to perform the operation described in the above-described wafer flow, thereby polishing a series of N wafers (that is, automatically polishing the N wafers). When the series of polishing is completed, the process proceeds to step S15.
• step S14 the control unit performs the operation described in the wafer flow described above in accordance with the setting of the M wafers in step S13, so that each unit performs a series of polishing of the M wafers (ie, The M wafers are automatically and continuously polished).
• step S15 the process proceeds to step S15.
• this series of polishing it is set in cassette C1.
• the unprocessed M unprocessed wafers W d are each stored in the cassette C4 as M force-processed wafers WP.
• the control unit not only polishes the wafer with the polishing pad 311c but also sets the polishing pad 311c in advance.
• the control unit swings the polishing arm 3 1 1 to polish the polishing head 3 1. 1a is moved upward to the pad conditioning device 3 17 and the polishing head 3 11a is lowered, and the polishing head 3 11a and the conditioner holding member 3 17 c are rotated. Rotate relative to condition polishing pad 3 1 1c.
• the conditioning in steps S12 and S14 is performed according to the currently set conditioning time (the latest setting time in steps S10, S19 and S30).
• the conditioning conditions in steps S12 and S14 are the same as the conditioning conditions in steps S6 and S26, except for the conditioning time.
• the present invention is not limited to this.
• step S15 the control unit causes the node thickness measuring device 319 to measure the thickness of the polishing pad 311c, as in step S2.
• step S3 the control unit determines that the pad thickness measured in step S15 is equal to or greater than a predetermined minimum control value d1 that determines the life of the polishing pad 311c. By determining whether or not the thickness is equal to or not, it is determined whether or not the life of the polishing pad 311c has expired (step S16). If the value is smaller than the minimum control value d1, the process proceeds to step S4. If the value is equal to or more than the minimum control value d1, the process proceeds to step S17.
• step S17 the control unit sets the parameters measured in step S15.
• the difference between the pad thickness and the pad thickness measured in step S3 is determined in step 12 or step S14 (depending on which step reached step S17).
• the average cutting rate of the polishing pad 311c in the series of polishing is calculated by dividing by the accumulated conditioning time of the conditioning.
• control unit determines whether or not the average cutting rate calculated in step S17 is equal to or greater than the minimum control value R1 that determines the life of the conditioner 317b. It is determined whether the life of 7b has expired (step S18).
• step S18 If it is determined in step S18 that the value is not less than the minimum control value R1 (that is, the life of the conditioner 317b has not expired), the next series of polishing (steps S12, S14)
• the conditioning time at which the amount of cutting of the polishing pad 311c by each conditioning of the polishing pad 311c performed at step S1 becomes a predetermined value is determined by the average cutting rate calculated in step S8. Then, the conditioning time (one time) is reset in the internal memory of the control unit as the conditioning time for the conditioning in the next series of polishing (step S19). Then, the process returns to step S1.
• the control unit includes the conditioner 3 in the above-described alarm unit.
• a warning to replace 17b is issued at one night or the like (Step S20).
• the control unit waits for the conditioner 317b to be replaced in step S21, and when the conditioner 317b is replaced, the pad thickness measuring device as in step S2.
• the thickness of the polishing pad 311c is measured (step S22).
• the control unit is a replacement detection sensor (not shown) for the conditioner 317b.
• the exchange of the conditioner 317b may be known by a signal from the controller, or if there is no such sensor, it may be known by a predetermined operation of the input device by an operator or the like.
• step S3 the control unit determines that the pad thickness measured in step S22 is equal to or greater than a predetermined minimum control value d1 that determines the life of the polishing pad 311c.
• a predetermined minimum control value d1 that determines the life of the polishing pad 311c.
• step S24 the controller replaces the polishing pad 311c with a new polishing pad by the pad exchanging device 318 as in step S4.
• step S25 the control section causes the thickness of the polishing pad 311c to be measured (step S25), and then proceeds to step S26.
• step S26 the control unit causes the conditioning device 317 to break-in the polishing pad 311c in the same manner as in step S6.
• the process of step S26 can be said to be the original break-in conditioning when the process proceeds from step S25 to step S26, but is performed when the process proceeds from YES in step S23 to step S26. In this case, the operation is exactly the same, but the quality of the new conditioner 317b is not the original break-in conditioning (the initial conditioning of the polishing pad 311c). This is a pre-operation to make a decision.
• step S27 the control unit causes the thickness of the polishing pad 311c to be measured.
• step S25 the control unit determines the pad thickness measured in step S25 or step S22 (this depends on whether or not step S25 has been reached via steps S24 and 25).
• Pad thickness measured in S27 The average cutting rate of the polishing pad 311c in step S26 is calculated by dividing the difference from the difference by the conditioning time of the break-in conditioning performed in step 26 (step S2). 8). Thereafter, the control unit determines whether or not the average cutting rate obtained in step S28 is within the range of not less than the minimum control value R1 and not more than the predetermined maximum control value R2.
• the pass / fail of the 317b is determined (step S29). If it is not within the range (if the conditioner 3 17 b is defective), the process returns to step S 20. On the other hand, if it is within the range (if the conditioner 3117b is good), the process proceeds to step S30.
• step S30 the control unit sets the polishing pad 311 by conditioning once in each of the polishing pads 311c performed in the next series of polishing (steps S12 and S14).
• the conditioning time at which the cutting amount of 1c becomes a predetermined value is determined from the average cutting rate calculated in step S28, and this conditioning time (one time) is used as the conditioning time for the next series of polishing. Reset to the internal memory of the control unit as the conditioning time during conditioning. Then, the process returns to step S1.
• step S3 is performed individually for the polishing pad thickness of each polishing head, and then for all polishing heads, the polishing pad thickness is set to the minimum control value (each polishing head). Only if this is the case, the process proceeds to step S11, and in other cases, the series polishing is not performed. Also, wafers that are actually polished The number of sheets is determined according to the results of the determinations in steps S 11 and S 13 regarding the polishing head of each polishing stage.
• the thickness of polishing pad 311c is measured in steps S2, S15, and S22, and the measurement is performed in steps S3, S16, and S23. If the measured thickness is smaller than the predetermined value d1, it is determined that the life of the polishing pad 311c has expired, and in that case, the polishing pad 311c is replaced with a new polishing pad. Therefore, according to the present embodiment, the life of the polishing pad can be accurately determined, and the polishing pad can be properly replaced. Therefore, the wafer can be polished with high accuracy, and it is possible to prevent a situation in which it is determined that the life of the polishing pad has expired as soon as possible, and the frequency of replacement of the polishing pad can be reduced. Running costs are reduced.
• the average cutting rate of polishing pad 311c is calculated in steps S17 and S8, and the average cutting rate is set to predetermined value R in steps S18 and S9. If it is lower than 1, it is determined that the life of the conditioner 3 17 b has expired, and the conditioner 3 17 b is replaced with a new conditioner. Therefore, according to the present embodiment, the life of the conditioner can be accurately determined, and the conditioner can be replaced properly. Therefore, the polishing pad can be properly conditioned, and the wafer can be accurately polished. Moreover, it is possible to prevent the conditioner from being judged that the life of the conditioner has expired fairly early. Running costs are reduced because less is required. '
• step S26 when a new conditioner is mounted on the pad conditioning apparatus, predetermined conditioning is performed in step S26, and steps S22 and S27 before and after the predetermined conditioning are performed.
• pad The thickness is measured, and based on the measurement result, an average cutting rate of the polishing pad is calculated in step S28, and if the average cutting rate is out of the predetermined range in step S29, the new cutting rate is calculated.
• the conditioner is determined to be defective, and step S20 is performed. Therefore, according to the present embodiment, the polishing pad can be conditioned (conditioning for polishing) by the conditioner having an appropriate cutting ability, and the desired polishing characteristics can be exhibited in the polishing pad. Thus, the wafer can be polished with high accuracy.
• the average cutting rate of the polishing pad calculated in steps S 18, S 9, and S 29 becomes the next cutting rate in steps S 19, S 9, and S 29.
• Conditioning conditions during conditioning in a series of polishing are fed back, so that the conditioning surface of the conditioner gradually wears out. In any case, the effect is greatly reduced, and the condition of the polished surface of the polishing pad after conditioning is almost constant for each wafer.Thus, it is necessary to stably and accurately polish a large number of wafers. Can be.
• steps S11 and S13 are performed, and a situation in which the life of the polishing pad is exhausted in the middle of a series of polishing is prevented. Therefore, from this point, a large number of wafers can be polished stably and accurately.
• the pad exchange devices 318, 328, 338 are provided, but these are not necessarily required in the present invention. If there is no pad exchange device 3 18, 3 2 8, 3 3 8, for example, an alarm indicating that the polishing pad should be exchanged may be generated in the operation in step S 4.
• the conditioner is replaced manually.
• a conditioner replacement device that automatically replaces the conditioner may be provided. In this case, instead of generating an alarm at step S20, the conditioner may be replaced by the conditioner replacement device.
• a quartz substrate, a glass substrate in addition to performing precise polishing control in the Cu-CMP process, for example, in addition to a wafer process such as an interlayer insulating film processing process and an STI process, a quartz substrate, a glass substrate, The same can be applied to a processing process for a ceramic substrate or the like.
• the polishing apparatus 1 is an example of a polishing apparatus that performs polishing using three stages of polishing stages 310, 320, and 330 using an index table 340 divided into four. there were.
• the present invention is not limited to this.
• a configuration in which polishing is performed in two stages of polishing stages, or a configuration in which four or more stages of polishing stages are provided may be employed.
• FIG. 6 is a flowchart showing a semiconductor device manufacturing process.
• step S200 an appropriate processing step is selected from the following steps S201 to S204. According to the selection, the process proceeds to any one of steps S201 to S204.
• Step S201 is an oxidation step of oxidizing the surface of the silicon wafer.
• Step S202 is a CVD process for forming an insulating film on the silicon wafer surface by CVD or the like.
• Step S203 is an electrode forming step of forming an electrode film on the silicon wafer by a process such as vapor deposition.
• Step S204 is an ion implantation step of implanting ions into the silicon wafer.
• Step S209 it is determined whether a CMP step is to be performed. If not, go to step S206. If yes, go to step S205.
• Step S205 is a CMP step.
• the polishing apparatus according to the present invention is used to flatten an interlayer insulating film, form a damascene by polishing a metal film on the surface of a semiconductor device, and the like. Is performed.
• Step S206 is a photolithography process.
• a resist is applied to the silicon wafer, a circuit pattern is printed on the silicon wafer by exposure using an exposure apparatus, and the exposed silicon wafer is developed.
• the next step S207 is an etching step in which portions other than the developed resist image are exposed by etching, and thereafter, the resist is peeled off, and the unnecessary resist after etching is removed.
• step S208 it is determined whether or not all necessary processes have been completed. If not, the process returns to step S200, and the previous steps are repeated to form a circuit pattern on the silicon wafer. . If it is determined in step S208 that all steps have been completed, the process ends.
• the polishing apparatus according to the present invention since the polishing apparatus according to the present invention is used in the CMP process, the processing accuracy in the CMP process is improved without using a polishing pad whose life has expired and using a conditioner. At the same time, running costs can be reduced. As a result, a semiconductor device having less manufacturing variation than the conventional semiconductor device manufacturing method can be manufactured at low cost. Further, a semiconductor device manufactured by the semiconductor device manufacturing method according to the present invention has a high yield and is inexpensive.
• the polishing apparatus according to the present invention is used in a CMP process of a semiconductor device manufacturing process other than the above semiconductor device manufacturing process. May be used.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
• Mechanical Treatment Of Semiconductor (AREA)
• Grinding-Machine Dressing And Accessory Apparatuses (AREA)
• Constituent Portions Of Griding Lathes, Driving, Sensing And Control (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=29996841

Family Applications (1)

Country Status (3)

Cited By (1)

Families Citing this family (17)

Citations (7)

Family Cites Families (4)

• 2002
  • 2002-06-28 JP JP2002189264A patent/JP4259048B2/ja not_active Expired - Lifetime
• 2003
  • 2003-06-27 TW TW092117510A patent/TWI271264B/zh not_active IP Right Cessation
  • 2003-06-27 WO PCT/JP2003/008216 patent/WO2004002681A1/ja not_active Ceased

Patent Citations (7)

Also Published As

Similar Documents

Legal Events