JP2004025413A - Determination method for life/quality of polishing pad or the like, conditioning method, device, semiconductor device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely determine a life of a polishing pad and a life of a conditioner. <P>SOLUTION: Thickness of the polishing pad 311c used for polishing a wafer Wd is measured with a pad thickness measurement meter 319. When the thickness is thinner than a predetermined value, it is determined that the life of the polishing pad 311c has expired. The polishing pad 311c is performed conditioning by a conditioner 317b of a pad conditioning device 317. The thickness of the polishing pad 311c is measured with the pad thickness measurement meter 319 before and after the conditioning. A mean cutting rate during the time of the conditioning of the conditioning of the polishing pad 311c is measured based on the thickness of the polishing pad 311c measured before and after the conditioning. When the mean cutting rate is lower than a predetermined value, it is determined that the life of the conditioner 317b has expired. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a polishing technique, and more 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. is there.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been provided a polishing apparatus for polishing a workpiece by relatively moving the polishing pad and the workpiece while applying a load between the polishing pad and the workpiece.
[0003]
As such a polishing apparatus, for example, a polishing apparatus for performing chemical mechanical polishing (Chemical Mechanical Polishing or Chemical Mechanical Planarization, hereinafter referred to as CMP) for global flattening of the surface of a semiconductor device wafer or the like is exemplified. be able to. CMP is a process of removing the unevenness of the surface of a wafer by using a chemical action (dissolving with a polishing agent or a solution) in combination with physical polishing. Thus, the polishing is advanced by pressing the wafer surface and causing the wafer to move relative to each other, thereby enabling uniform polishing within the wafer surface.
[0004]
In such a polishing apparatus, the polishing surface of the polishing pad deteriorates due to progress of clogging according to the polishing time, so that good processing is continued by performing regular conditioning (also referred to as dressing). Will be maintained.
[0005]
The 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 relatively moving the polishing pad and the conditioner. As the conditioner, for example, a tool in which abrasive grains such as diamond particles are distributed over the whole of an annular or circular conditioning surface is used. The relative movement is performed, for example, by rotating both the polishing pad and the conditioner.
[0006]
The thickness of the polishing pad becomes thinner due to abrasion caused by polishing of an object to be polished such as a wafer and the abrasion (cutting) caused by the above-mentioned conditioning. run out. Therefore, it is necessary to replace the polishing pad with a new polishing pad. Therefore, conventionally, the cumulative time of polishing by the polishing pad, the cumulative time of conditioning, the number of polished objects to be polished, and the number of conditioning, the life of the polishing pad is determined, when it is determined that the life is exhausted , The polishing pad was replaced with a new one. The polishing pad may be manually replaced by an operator, and a device for automatically replacing the polishing pad is also provided (for example, JP-A-2001-148361).
[0007]
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 also wears out due to the conditioning of the polishing pad, so that the desired conditioning characteristics cannot be obtained and the life of the conditioning pad ends. Therefore, conventionally, the life of the conditioner is determined based on the accumulated time and the number of times of conditioning by the conditioner, and when it is determined that the life has expired, the conditioner is replaced with a new one. The new conditioner has always been used for conditioning a polishing pad without special checks, assuming that it has desired conditioning characteristics.
[0008]
Further, conventionally, the conditioning of the polishing pad has been performed every time a predetermined number of objects to be polished are polished by the polishing pad. However, the conditioning is performed every time under the same conditioning conditions.
[0009]
[Problems to be solved by the invention]
However, in the conventional method for determining the life of a polishing pad, the life of the polishing pad is determined based on the accumulated time and the number of times of polishing and conditioning. Therefore, the life of the polishing pad cannot be accurately determined. For this reason, in actuality, it is determined that the life of the polishing pad has expired fairly early, even though the desired polishing characteristics are still sufficiently obtained in anticipation of a considerable margin, and the polishing pad is replaced with a new polishing pad. Was. Therefore, the running cost of the polishing apparatus has increased. If it is not determined that the life of the polishing pad has expired early in anticipation of a sufficient margin, the life of the polishing pad cannot be accurately determined, so that the polishing pad has desired polishing characteristics. In spite of the disappearance, the object to be polished is polished, and the object to be polished cannot be polished with high accuracy, resulting in a fatal result.
[0010]
Further, in the conventional method for determining the life of a conditioner, 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 in spite of the fact that the desired conditioning characteristics are still obtained sufficiently, it is determined that the life of the conditioner has expired quite early, and a new conditioner is determined. Had been replaced. Therefore, the running cost of the polishing apparatus has increased. If it is not determined that the life of the conditioner has expired early enough in anticipation of the allowance, the life of the conditioner cannot be accurately determined, so that the conditioner can obtain desired conditioning characteristics. Although the polishing pad has disappeared, the polishing pad is conditioned, and as a result, the polishing pad cannot exhibit desired polishing characteristics. As a result, the object to be polished cannot be polished with high accuracy. Results.
[0011]
Furthermore, it has been found that new conditioners do not always have the desired conditioning properties. For example, in the case of a new conditioner, the cutting ability by abrasive grains and the like is too high, and the polishing surface of the polishing pad becomes too rough beyond the stage of recovering the clogging of the polishing pad. It has been found that may not be able to exhibit desired polishing characteristics. Therefore, as described above, when a new conditioner is used for conditioning a polishing pad without any check, the polishing pad cannot exhibit desired polishing characteristics, and as a result, the object to be polished can be accurately polished. There was a risk of causing a fatal result. However, conventionally, there has been no effective method for determining the quality of a new conditioner.
[0012]
Conventionally, the 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, but is performed under the same conditioning conditions every time. However, since the conditioning surface of the conditioner is gradually consumed, the condition of the polishing surface of the polishing pad after the 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.
[0013]
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.
[0014]
Another object of the present invention is to provide a conditioner life determining method capable of accurately determining the conditioner life.
[0015]
It is another object of the present invention to provide a conditioner quality determination method that can appropriately determine the quality of a new conditioner.
[0016]
Still another object of the present invention is to provide a method for conditioning a polishing pad, which can polish each object to be polished in the same manner.
[0017]
Another object of the present invention is to provide a polishing apparatus that can reduce running costs.
[0018]
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.
[0019]
Still another object of the present invention is to provide a semiconductor device manufacturing method capable of manufacturing a semiconductor device at a lower cost than a conventional semiconductor device manufacturing method, and a low-cost semiconductor device.
[0020]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a method for determining the life of a polishing pad according to a first aspect of the present invention is a method for determining the life of a polishing pad used for polishing an object to be polished. Is measured, and when the measured thickness of the polishing pad is smaller than a predetermined value, it is determined that the life of the polishing pad has expired.
[0021]
A method for determining the life of a conditioner according to a second aspect of the present invention is a method for determining the life of a conditioner used for conditioning a polishing pad used for polishing an object to be polished. Conditioning the cumulative conditioning time using a conditioner, before and after conditioning the cumulative conditioning time, measure the thickness of the polishing pad, based on the thickness of the polishing pad measured before and after the conditioning of the cumulative conditioning time. Then, an average cutting rate of the polishing pad during the cumulative conditioning time is obtained, and when the average cutting rate is lower than a predetermined value, it is determined that the life of the conditioner has expired.
[0022]
The quality determination method for a conditioner according to the third aspect of the present invention is a quality determination method for determining quality of a new conditioner used for conditioning a polishing pad used for polishing an object to be polished. Condition the cumulative conditioning time using the new conditioner, measure the thickness of the polishing pad before and after conditioning the cumulative conditioning time, and measure the thickness of the polishing pad before and after conditioning the cumulative conditioning time. And determining an average cutting rate of the polishing pad during the cumulative conditioning time, and determining that the new conditioner is defective when the average cutting rate is out of a predetermined range.
[0023]
A conditioning method for a polishing pad according to a fourth aspect of the present invention is a conditioning method for conditioning a polishing pad used for polishing an object to be polished with a conditioner, wherein the polishing pad is subjected to predetermined conditions using the conditioner. Condition one or more times, before and after the one or more conditioning, measure the thickness of the polishing pad, based on the thickness of the polishing pad measured before and after the one or more conditioning, based on the polishing pad Determine the average cutting rate in the one or more conditioning, based on the average cutting rate, set a conditioning condition at the time of the next conditioning of the one or more conditioning, the next conditioning, Condition set above It is performed in accordance with grayed conditions.
[0024]
In the polishing pad conditioning method according to a fifth aspect of the present invention, in the fourth aspect, the conditioning condition is a conditioning time.
[0025]
A polishing apparatus according to a sixth aspect of the present invention polishes the object by relatively moving the polishing pad and the object while applying a load between the polishing pad and the object. In the polishing apparatus, a measuring unit for measuring the thickness of the polishing pad, and an alarm indicating that the polishing pad should be replaced with a new polishing pad when the thickness of the polishing pad measured by the measuring unit is smaller than a predetermined value. Or a means for automatically replacing the polishing pad with a new polishing pad.
[0026]
A polishing apparatus according to a seventh aspect of the present invention polishes the object by relatively moving the polishing pad and the object while applying a load between the polishing pad and the object. In the polishing apparatus, a conditioning unit having a conditioner and conditioning the polishing pad with the conditioner, at a first timing and a second timing thereafter, a measuring unit that measures the thickness of the polishing pad, The accumulation of the polishing pad by the conditioner in the period from the first timing to the second timing based on the thickness measured at the first timing and the thickness measured at the second timing. A calculating unit for calculating an average cutting rate during a conditioning time; and a controller for calculating the average cutting rate when the average cutting rate is lower than a predetermined value. And means for exchanging the automatic new conditioner or the conditioner generating an alarm to the effect that exchange the new conditioner of conditioners, those having a.
[0027]
A polishing apparatus according to an eighth aspect of the present invention polishes the object by relatively moving the polishing pad and the object while applying a load between the polishing pad and the object. In the polishing apparatus, a conditioning section having a conditioner and conditioning the polishing pad with the conditioner, and a second conditioner in which a new conditioner is mounted on the conditioning section and the new conditioner is used for conditioning the polishing pad. At a first timing, and at a second timing after conditioning the polishing pad using the new conditioner thereafter, a measurement unit that measures the thickness of the polishing pad, and a measurement at the first timing Based on the thickness and the thickness measured at the second timing, A computing unit that computes an average cutting rate during a cumulative conditioning time of the polishing pad by the conditioner during a period from the first timing to the second timing, and the average cutting rate is outside a predetermined range. In such a case, there is provided a means for generating an alarm indicating that the conditioner should be further replaced with a new conditioner, or automatically replacing the conditioner with a new conditioner.
[0028]
The present invention provides a polishing apparatus according to a ninth aspect, wherein the polishing pad is polished by relatively moving the polishing pad and the workpiece while applying a load between the polishing pad and the workpiece. In the polishing apparatus, a conditioning unit having a conditioner and conditioning the polishing pad with the conditioner, at a first timing and a second timing thereafter, a measuring unit that measures the thickness of the polishing pad, Based on the thickness measured at the first timing and the thickness measured at the second timing, during the period from the first timing to the second timing, the conditioner adjusts the polishing pad by the conditioner. Means for determining an average cutting rate during the cumulative conditioning time, and, based on the average cutting rate, It is obtained and a conditioning condition setting unit for setting a conditioning condition of the next conditioning after between.
[0029]
The polishing apparatus according to a tenth aspect of the present invention is the polishing apparatus according to the ninth aspect, wherein the conditioning condition is a conditioning time.
[0030]
A polishing apparatus according to an eleventh aspect of the present invention polishes the object by relatively moving the polishing pad and the object while applying a load between the polishing pad and the object. In the polishing apparatus, having a conditioner, the polishing pad with the conditioner, every time the polishing pad polished a predetermined number of the object to be polished, a conditioning unit for conditioning, the first timing and the subsequent first At a timing of 2, after the second timing, based on the measuring unit that measures the thickness of the polishing pad and the thickness measured at the first timing and the thickness measured at the second timing, The number of the objects to be polished by the polishing pad, the thickness of the polishing pad to be predicted when it is assumed that the number of the objects to be polished is predetermined. Is obtained and a means to limit the number below not be thinner.
[0031]
A semiconductor device manufacturing method according to a twelfth aspect of the present invention includes the step of flattening the surface of a semiconductor wafer using the polishing apparatus according to any one of the sixth to eleventh aspects.
[0032]
A semiconductor device according to a thirteenth aspect of the present invention is manufactured by the semiconductor device manufacturing method according to the twelfth aspect.
[0033]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, 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 according to the present invention will be described with reference to the drawings. I do.
[0034]
[First Embodiment]
[0035]
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 a state of processing a wafer by the polishing apparatus 1 shown in FIG. FIG. 3 is a schematic cross-sectional view schematically showing main components located on the first polishing stage in the polishing apparatus 1 shown in FIG. 1 when viewed from the side. In FIG. 2, a polishing state monitoring device 50a, which will be described later, is omitted for convenience of illustration.
[0036]
The polishing apparatus 1 according to the present embodiment is an example of a CMP apparatus for precisely flat-polishing a semiconductor wafer as an object to be polished in a three-stage polishing process.
[0037]
As shown in FIGS. 1 and 2, the polishing apparatus 1 includes a cassette index section 100, a wafer cleaning section 200, and a polishing section 300. Each section is partitioned to form a clean chamber. Note that an automatic opening / closing shutter may be provided between the respective rooms.
[0038]
The cassette index unit 100 includes a wafer mounting table 120 on which cassettes (also referred to as carriers) C1 to C4 holding a plurality of wafers are mounted, and a non-processed wafer taken out of the cassette and a cleaning machine temporary mounting table of the cleaning unit 200. And a first transfer robot 150 that carries the processed wafers that have been carried into the wafer 211 and cleaned by the wafer cleaning unit 200 after the polishing processing, in a cassette.
[0039]
The first transfer robot 150 is an articulated arm type robot having two articulated arms 153a and 153b, and includes a base 151, a swivel table 152 capable of horizontally rotating and vertically moving on the base 151, and a swivel table 152. The two articulated arms 153a, 153b attached above, the A-arm 155a and the B-arm 155b (B-arm 155b) attached to the distal ends of the articulated arms 153a, 153b so as to be extendable and contractible with respect to each arm. It is offset below the A-arm 155a and is positioned vertically above and below in FIGS. 1 and 2). A holding part for mounting and sucking and holding a wafer is formed at the tip of the A arm 155a and the B arm 155b. The base 151 is provided with a linear moving device that can move horizontally along a linear guide 160 provided on the floor.
[0040]
For this reason, 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 table 152 to set the A-arm 155a or the B-arm 155b to the desired slot height. Then, the multi-joint arm 153a and the A-arm 155a, or the multi-joint arm 153b and the B-arm 155b are operated, and the unprocessed wafer in the target slot is sucked by the holding portion at the tip of the A-arm 155a or the B-arm 155b. The wafer can be held and taken out, or a processed wafer can be stored in a target slot.
[0041]
Note that these two pairs of arms 155a and 155b, which are arranged offset in the vertical direction, are functionally equivalent, and either one is used for taking out or storing, or only one arm is used for both purposes. In the illustrated polishing apparatus, an unprocessed wafer is taken out of the cassette by the lower B-arm 155b, and the processed wafer after cleaning is set in the cassette by the upper A-arm 155a. I have.
[0042]
The wafer cleaning unit 200 has a four-chamber configuration including a first cleaning chamber 210, a second cleaning chamber 220, a third cleaning chamber 230, and a drying chamber 240, and the polished wafers are processed in the first cleaning chamber 210 → the second cleaning chamber. The removal and cleaning of the slurry, the polishing processing liquid, the abrasive wear powder and the like which are sequentially sent in the order of 220 → third cleaning chamber 230 → drying chamber 240 and adhered in the polishing section 300 are performed. For example, in the first cleaning chamber 210, both-side cleaning with a rotating brush, in the second cleaning chamber 220, surface pencil cleaning under ultrasonic vibration, in the third cleaning chamber 230, spinner cleaning with pure water, and in the drying chamber 240, under a nitrogen atmosphere. Is configured to perform the drying process. The unprocessed wafer before the polishing process passes through the wafer cleaning unit 200 from the cassette index unit 100 via the cleaning machine temporary placing table 211 and is carried into the wafer polishing unit 300 without going through the above-described cleaning process.
[0043]
The polishing section 300 is provided so as to surround the index table 340 from the outer periphery corresponding to a position where the index table 340 is stopped by rotating the index table 340 at intervals of 90 degrees by the operation of a stepping motor or the like. It comprises a first polishing stage 310, a second polishing stage 320, a third polishing stage 330, and a transfer stage 350 for loading an unprocessed wafer into the index table 340 and unloading a processed wafer. The polishing stage may be called a polishing zone or a polishing chamber.
[0044]
In 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 so as to be exposed on the upper surface of the table, and the chucks V1 to V4 are arranged on the index table 340 in a horizontal plane ( In addition to being rotatably supported in a plane parallel to the paper surface in FIG. 1), a high-speed rotation and stop holding are freely mounted by driving means such as an electric motor or an air motor provided inside the index table 340. . The diameters of the chucks V1 to V4 are slightly smaller than the diameters of the wafers, and are configured to be able to grip the outer peripheral end of the wafer held by the chucks V1 to V4.
[0045]
The three polishing stages of the first polishing stage 310, the second polishing stage 320, and the third polishing stage 330 are respectively provided with a polishing arm 311 which is swingable in the horizontal direction and vertically movable in the vertical direction with respect to the index table 340. , 321 and 331 are provided.
[0046]
As shown in FIG. 3, a polishing head 311a hanging from the polishing arm 311 and rotatable at a high speed in a horizontal plane is attached to the tip of the polishing arm 311. The lower end surface of the polishing head 311a is rotated relative to the wafer. Has a polishing pad 311c as a polishing body for flat polishing. In the present embodiment, the polishing pad 311c is mounted on a mounting plate 311b, and the mounting plate 311b is held by a vacuum head on a polishing head 311a. The polishing pad 311c is supported by a pad exchange device 318 described later by a support member 311b. Everything is automatically replaced. As such a polishing head 311a and a pad exchange device 318, for example, those disclosed in JP-A-2001-148361 can be adopted. Although not shown in the drawing, a polishing head that is suspended from the polishing arms 321 and 331 and that is rotatable at high speed in a horizontal plane is also attached to the tip of each of the polishing arms 321 and 331. Has a polishing pad as a polishing body for flat polishing a wafer by relative rotation of.
[0047]
As shown in FIGS. 1 and 2, each of the polishing stages 310, 320, and 330 has a pad thickness measuring device 319, 329, and 339 for measuring the thickness of the polishing pad, and a pad conditioning for conditioning the surface of the polishing pad. Devices 317, 327, and 337 and pad exchange devices 318, 328, and 338 for automatically exchanging polishing pads are attached.
[0048]
In the present embodiment, as shown in FIG. 3, a commercially available contact stylus type displacement meter is used as the pad thickness measuring device 319, and the stylus 319a comes into contact with the polishing surface of the polishing pad 311c to increase its height. The thickness distribution of the polishing pad 311c in the radial direction can be measured by sliding the stylus 319a in the radial direction of the polishing pad 311c in response to the vertical movement. In the present embodiment, an average value of the thickness distribution in the radial direction (a maximum value or a minimum value may be used) is adopted as the thickness of the polishing pad 311c. For example, the thickness of only one point on the polishing surface of the polishing pad 311c may be measured. As the pad thickness measurement device 319, for example, an optical displacement meter may be used instead of the contact stylus displacement meter. The pad thickness measuring devices 329 and 339 have the same configuration as the pad thickness measuring device 319.
[0049]
Further, in the present embodiment, as shown in FIG. 3, the pad conditioning device 317 holds a conditioner 317b having a ring-shaped conditioning surface 317a on which ring-shaped diamond abrasive grains are distributed, and a conditioner 317b. And a rotation mechanism 317d for rotating the conditioner holding member 317c. The polishing surface of the polishing pad 311c is conditioned by bringing the polishing surface of the polishing pad 311c into contact with the conditioning surface 317a of the conditioner 317b, applying a load, and rotating each. The pad conditioning devices 327 and 337 have the same configuration as the pad conditioning device 317. In this embodiment, the conditioners of the pad conditioning devices 317, 327, and 337 can be manually replaced by an operator. However, similarly to the case of the polishing pad, the conditioners for automatically replacing the conditioners are used. An exchange device may be provided.
[0050]
The relative positions of the polishing arm, the chuck, the pad thickness measuring device, the pad conditioning device, and the pad exchanging device in each of the polishing stages 310, 320, 330 are defined so as to be located on the swinging circumference of the polishing head at the tip of the polishing arm. Have been. For this reason, for example, when polishing is performed on the first polishing stage 310, the polishing arm 311 is swung to move the polishing head onto the chuck V4, the polishing head and the chuck V4 are relatively rotated, and the polishing arm 311 is lowered. Thus, the polishing pad is pressed onto the wafer to perform the polishing process. It goes without saying that the polishing agent (slurry) is interposed between the polishing pad and the wafer during the polishing process. In the final stage of the polishing process, after the abrasive on the object to be polished is washed away by a water supply device (not shown), drainage is performed by, for example, rotating a chuck.
[0051]
When the polishing process is completed and the polishing arm 311 is slightly raised, the index table 340 can be rotated. At this time, the polishing arm 311 is swung at a predetermined timing to be described later, the thickness of the polishing pad is measured by the pad thickness measuring device 319, and the polishing arm 311 is further swung every predetermined number of times of polishing (that is, every number of wafers). The polishing pad 311c is moved to perform conditioning (conditioning) to correct clogging and irregularities of the polishing pad 311c by the pad conditioning device 317, and the polishing arm 311 is further swung at a timing described later to replace the polishing pad 311c with the pad exchange device 318. The polishing pad 311c is moved upward, and the polishing pad 311c is automatically replaced by this apparatus.
[0052]
An arm position detector (not shown) for detecting a swing angle position of the arm is attached to the polishing arm 311, and detects a polishing processing position, a pad thickness measurement position, a conditioning position, and a pad replacement position of the polishing arm 311. are doing.
[0053]
As shown in FIG. 1, each polishing stage is provided with a polishing status monitor 50a for optically monitoring the polishing status of the wafer being polished, and detects a decrease in film thickness during polishing in real time. It is possible. As the polishing state monitoring device 50a, for example, an apparatus disclosed in JP-A-2000-40680 can be used. In the present embodiment, the polishing state monitoring device 50a has arms 61 that extend substantially parallel to the polishing arms of the respective polishing stages and can swing in the horizontal direction. The arm 61 incorporates an optical fiber or the like, and from the tip of the arm 61 irradiates the probe light locally onto the wafer being polished while being held by the chuck, and receives the reflected light from the wafer for a predetermined time. It is designed to be guided to places. The arm 61 is configured to swing in synchronization with the polishing arm during polishing in order to avoid mechanical interference with the polishing arm. In the present embodiment, 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.
[0054]
The above configuration and operation are the same for the second polishing stage 320 and the third polishing stage 330.
[0055]
The transfer stage 350 is provided with a second transfer robot 360 and a third transfer robot 370. The second transfer robot 360 is a multi-joint arm type robot similar to the above-described first transfer robot 150, and has two multi-joints that are swingably mounted on a swivel table 362 that can be horizontally turned and vertically moved. The arm 363a, 363b and the A-arm 365a and the B-arm 365b are attached to the distal ends of the articulated arms 363a, 363b so as to be extendable and contractible. The A-arm 365a and the B-arm 365b are vertically offset from each other, and a holding portion for mounting and sucking and holding a wafer is formed at the tip of each of the arms 365a and 365b.
[0056]
The third transfer robot 370 is provided with a swing arm 371 that is swingable in the horizontal direction and vertically up and down with respect to the index table 340, and a tip end of the swing arm 371 that is horizontally movable with respect to the swing arm 371. The rotating arm 372 is rotatably mounted, and includes an A clamp 375a and a B clamp 375b suspended at both ends of the rotating arm 372 to grip the outer peripheral end of the wafer. 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 below the A clamp 375a and the B clamp 375b in the figure, an A temporary placing table 381 on which an unprocessed wafer is placed, respectively. And a B temporary placing table 382 on which a polished wafer is placed.
[0057]
Therefore, by swinging the swing arm 371 of the third transfer robot 370 and further turning the rotation arm 372, the A clamp 375a or the B clamp 375b can be moved onto the chuck V1 of the index table 340. At this position, the swing arm 371 is lowered, and the wafer on the chuck is clamped and received by the A clamp 375a or the B clamp 375b, or a new wafer can be placed and held on the chuck.
[0058]
Since a polishing solution containing slurry is attached to the wafer after polishing, an arm and a clamp for loading the wafer before polishing and an arm and a clamp for discharging the wafer after polishing are used. Of the A and B arms 365a and 365b which are distinguished and vertically offset, the upper A arm 365a is an unloading wafer loading arm, the lower B arm 365b is a loading arm, and an A clamp. 375a is defined as a carry-in clamp and B clamp 375b is defined as a carry-out clamp.
[0059]
Next, the operation of the polishing apparatus 1 configured as described above will be described. First, the operation of the polishing apparatus 1 will be described, focusing on the flow of the wafer, and omitting the operations relating to pad thickness measurement, pad exchange, conditioning, and conditioner exchange. 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.
[0060]
In the following description, a wafer (hereinafter, referred to as an unprocessed wafer) before polishing by the polishing apparatus 1 is divided into three stages of a first polishing process P1, a second polishing process P2, and a third polishing process P3. An example in which the substrate is polished flat by polishing by CMP will be described. In the following example, the first polishing process P1, the second polishing process P2, and the third polishing process P3 are performed by the first polishing stage 310, the second polishing stage 320, and the third polishing stage 330, respectively. Has become.
[0061]
In the second polishing process P2 and the third polishing process P3, the polishing process is temporarily terminated when the polishing end point is detected by the polishing state monitoring device 50a. On the other hand, in this example, the primary polishing process P1 is a preceding polishing process of the secondary polishing process P2, and it is not necessary to detect the end point. The process is to be terminated, and the process is terminated at a predetermined polishing processing time tp1.
[0062]
2, the unprocessed wafers Wd set in the cassette C1 of the cassette index unit 100 are sequentially polished by the polishing unit 300 to become processed wafers Wp. The flow of wafers until they are stored in the cassette C4 is indicated by dotted lines and arrows. The operations of the transfer robots 150, 360, 370, the index table 340, the chucks V1 to V4, the polishing arms 311, 321, 331, and the polishing head are controlled by a control unit such as a personal computer (not shown). Controls these operations based on a preset control program. Although not shown in the drawings, the polishing apparatus 1 also includes an alarm unit for issuing an alarm described below, and an input device for giving various instructions and the like by an operator. The alarm unit may generate one of a visual alarm and an audible alarm, or may generate both of them.
[0063]
First, when the polishing apparatus 1 is started and polishing is started, the first transfer robot 150 moves to the position of the cassette C1 and horizontally turns and raises / lowers the swivel table 152 so that the B-arm 155b moves the wafer to the target. The wafer is moved to the slot height, the multi-joint arm 153b and the B-arm 155b are extended, and the unprocessed wafer Wd in the slot is sucked and held by the holding portion at the tip of the B-arm 155b. Then, the turning table 152 is turned by 180 degrees toward the wafer cleaning section 200, and the unprocessed wafer Wd is placed on the temporary washing machine 211 provided in the cleaning section 200.
[0064]
When the unprocessed wafer Wd is placed on the temporary placing table 211, the second transfer robot 360 of the loading stage 350 facing the wafer cleaning chamber 200 across the wafer cleaning chamber 200 operates the swivel table 362 to clean the tip of the A-arm 365a. The arm is rotated toward the temporary machine stand 211, the multi-joint arm 363a and the A arm 365a are extended, and the unprocessed wafer Wd on the temporary machine stand 211 is suction-held by the holding section at the tip of the A arm. When the unprocessed wafer Wd is held, the multi-joint arm 363a and the A-arm 365a are contracted and the swivel table 362 is turned to invert, and the multi-joint arm 363a and the A-arm 365a are extended again to extend the unprocessed wafer. The wafer Wd is placed on the A temporary placing table 381.
[0065]
When the unprocessed wafer Wd is placed on the A temporary placing table 381, the third transfer robot 370 descends, grips the unprocessed wafer Wd with the A clamp 375a, and rises to a predetermined height after the gripping. To wait until the positioning of the index table 340 is completed (standby posture). When the position of the index table 340 is stopped, the swing arm 371 and the swing arm 372 are swung and swung to place the unprocessed wafer on the chuck V1 and hold it by suction. Then, the third transfer robot 370 rises after the release of the clamp, swings and swings the swing arm 371 and the swing arm 372, grips the next unprocessed wafer Wd with the A clamp 375a, and holds the next unprocessed wafer Wd at a predetermined height. Waits for the next index operation at the standby position.
[0066]
Thereafter, the polishing process in the polishing section 300 is started. The flow from when the unprocessed wafer Wd carried into the carry-in stage 350 is carried out of the transfer stage 350 from the first polishing stage 310 through the second polishing stage 320 and the third polishing stage 330 is as follows.
[0067]
In the following description, the progress from the processing of one unprocessed wafer Wd in each stage to the storage of the processed wafer as a processed wafer will be described in chronological order. New wafers are sequentially loaded, new processed wafers are unloaded each time the index table 340 is rotated, and operations relating to different wafers are simultaneously performed in each stage in parallel.
[0068]
When the unprocessed wafer Wd is sucked and held on the chuck V1 and the third transfer robot 370 is evacuated from above the index table 340, the index table 340 is turned 90 degrees clockwise (clockwise) in FIGS. Then, the unprocessed wafer Wd is positioned on the first polishing stage 310 (V4 position in FIGS. 1 and 2). At this time, the polishing arm 311 is simultaneously swung to move the polishing head onto the unprocessed wafer Wd.
[0069]
When the positioning of the index table 340 is stopped, 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 press the polishing pad at the lower end of the polishing head onto the wafer, thereby performing the first polishing P1. Do. During the polishing, the polishing arm 311 is swung in a minute range so that the polishing pad reciprocates between the rotation center of the wafer and the outer peripheral end while supplying the slurry from the axis of the polishing head to move the wafer. Polish uniformly and flat. In the transfer stage 350, a new unprocessed wafer is loaded onto the chuck V2 by the third transfer robot 370 during the primary polishing.
[0070]
The primary polishing process P1 in the first polishing stage 310 is time-controlled as described above, and after a predetermined polishing time tp1 has elapsed, the polishing arm 311 is raised to perform the polishing process in the first polishing stage 310. Stop. Thereafter, the 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 first polishing stage 310 is completed). Wait for
[0071]
If the operation of the index table 340 is possible, the index table 340 is rotated 90 degrees clockwise again, and the wafer after the first polishing process P1 is moved to the second polishing stage 320 (V3 in FIGS. 1 and 2). Position). At this time, simultaneously, the polishing arm 321 is swung to move the polishing head onto the wafer. Then, the polishing arm 321 is lowered, and a polishing process (second polishing process P2) is performed on the second polishing stage 320 by the same operation as the first polishing process P1.
[0072]
The second polishing process P2 in the second polishing stage 320 is a so-called end point detection process. When it is determined that the processed film thickness detected by the polishing state monitoring device 50a of the second polishing stage 320 has decreased to a predetermined film thickness, the polishing arm 321 is raised and the second polishing stage 320 The polishing process is stopped, and washing and draining for washing off the abrasive (slurry) on the object to be polished are performed.
[0073]
Next, the control unit determines whether or not the operation of the index table 340 is possible (ie, whether or not the operation in a stage other than the second polishing stage 320 is completed). Wait for it to be.
[0074]
If the operation of the index table 340 is possible, the index table 340 is again rotated 90 degrees clockwise, and the wafer after the second polishing P2 is positioned on the third polishing stage 330 (V2 position in the figure). I do. 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.
[0075]
The third polishing process P3 in the third polishing stage 330 is a so-called end point detection process, similarly to the second polishing process P2. When it is determined that the processed film thickness detected by the polishing state monitoring device 50a of the third polishing stage 330 has decreased to a predetermined film thickness, the control unit raises the polishing arm 331 and moves the polishing arm 331 to the third position. The polishing at the polishing stage 330 is stopped.
[0076]
Next, the 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). Wait for it to be.
[0077]
If the operation of the index table 340 is possible, the index table 340 is again rotated 90 degrees clockwise, and the wafer after the third polishing P3 is transferred to the transfer stage 350 (V1 position in FIGS. 1 and 2). Position. When the position of the index table 340 is stopped, the third transfer robot 370 swings and swings the swing arm 371 and the swing arm 372 to unload the polished processed wafer Wp, and unloads the next unprocessed wafer Wp. The processed wafer Wd is loaded onto the chuck V1 and is sucked and held by the chuck V1, and the above operation is repeated.
[0078]
When the processed wafer Wp is placed on the B temporary placing table 382 and the third transfer robot 370 stops at the standby position, the second transfer robot 360 operates the swivel table 362, the articulated arm 363b, and the B arm 365b to move the B arm. The processed wafer Wp on the temporary storage table B 382 is sucked and held by the holding section at the tip, the swivel table 362 is swiveled, and the multi-joint arm 363b and the B arm 365b are operated to extend, so that the cleaning machine entrance of the cleaning section 200 is performed. The processed wafer Wp is mounted on 216.
[0079]
In the cleaning unit 200, both-side cleaning with a rotating brush in the first cleaning chamber 210, surface pencil cleaning under ultrasonic vibration in the second cleaning chamber 220, spinner cleaning with pure water in the third cleaning chamber 230, and drying in the drying chamber 240 A drying process is performed under a nitrogen atmosphere. Then, the finished product wafer thus cleaned is taken out of the cleaning unit 200 by the A arm 155a of the first transfer robot 150 in the cassette index unit 100, and stored in the designated slot of the cassette C4.
[0080]
As described above, the unprocessed wafer Wd set in the cassette C1 of the cassette index unit 100 is sequentially polished by the polishing unit 300 to become a processed wafer Wp, and is cleaned by the wafer cleaning unit 200, and the cassette C4 of the cassette index unit 100 is cleaned. The flow of the wafer until it is stored in the above has been described.
[0081]
In the polishing apparatus 1 according to the present embodiment, the control unit automatically and continuously outputs a plurality of wafers (for example, a plurality of wafers stored in the cassette C1) from an operator via an input device (not shown). When a command to start polishing (here, referred to as “series polishing”) is received, basically, for each of these wafers, operations relating to different wafers are simultaneously performed in parallel at each stage. Processing according to the flow of the wafer described above is performed.
[0082]
Next, focusing on one operation related to pad thickness measurement, pad replacement, conditioning, and conditioner replacement, which are characteristic operations of the present embodiment, attention is focused on one polishing stage 310, and flowcharts shown in FIGS. 4 and 5 are shown. The operation of the polishing apparatus 1 will be described with reference to FIG. Note that FIGS. 1 to 3 are also referred to.
[0083]
In the following description, it is assumed that only the first polishing stage 310 exists as a polishing stage for easy understanding. The actual operation in consideration of the second polishing stage 320 and the third polishing stage 330 will be described later.
[0084]
The control unit first determines whether or not the start command for the series polishing has been obtained from the input device (step S1). If the start command has not been obtained, the control unit waits until it is obtained. This command specifies how many wafers are to be continuously polished. Here, it is assumed that N wafers have been designated to be polished continuously.
[0085]
When a series polishing start command is obtained, the control unit swings the polishing arm 311 to move the polishing head 311a above the pad thickness measuring device 319, and the pad thickness measuring device 319 measures the thickness of the polishing pad 311c. (Step S2). As described above, 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 thickness distribution in the radial direction, but the average value is preferable.
[0086]
Next, the control unit determines whether the pad thickness measured in step S2 is equal to or greater than a predetermined minimum management value d1 that determines the life of the polishing pad 311c, thereby determining the life of the polishing pad 311c. It is determined whether or not has run out (step S3).
[0087]
If it is determined in step S2 that the value is not less than the minimum management value d1 (that is, the life of the polishing pad 311c has not expired), the process proceeds to step S11 described below. On the other hand, if it is determined in step S2 that the thickness is smaller than the minimum management 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.
[0088]
In step S4, the control unit swings the polishing arm 311 to move the polishing head 311a above the pad changing device 318, and causes the device 318 to change the polishing pad 311c to a new polishing pad. Thereafter, 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).
[0089]
Next, the control unit swings the polishing arm 311 to move the polishing head 311a above the pad conditioning device 317, lowers the polishing head 311a, and rotates the polishing head 311a and the conditioner holding member 317c, respectively. The polishing pad 311c is rotated to perform break-in conditioning (step S6). The break-in conditioning is a conditioning that is usually performed on a new polishing pad. For example, the conditioning time is longer than that of the normal conditioning (the conditioning performed in steps S12 and S14), and the conditioner 317b is used. The cutting amount of the polishing pad 311c is relatively large.
[0090]
Next, the control unit causes the pad thickness measuring device 319 to measure the thickness of the polishing pad 311c as in step S2 (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, thereby obtaining the polishing pad 311c in step S6. An average cutting rate is calculated (step S8).
[0091]
Thereafter, the control unit determines whether or not the life of the conditioner 317b has expired by determining whether or not the average cutting rate calculated in step S8 is equal to or greater than a minimum management value R1 that determines the life of the conditioner 317b. A determination is made (step S9).
[0092]
If it is determined in step S9 that the value is equal to or more than the minimum management value R1 (that is, the life of the conditioner 317b has not expired), each one of the polishing pads 311c to be performed in the next series of polishing (steps S12 and S14 to be described later). The conditioning time (one time) at which the amount of cutting of the polishing pad 311c by the previous conditioning becomes a predetermined value is obtained from the average cutting rate calculated in step S8, and this conditioning time is determined by the conditioning in the next series of polishing. The conditioning time is reset in the internal memory of the control unit (step S10). Then, the process returns to step S1.
[0093]
In step S11, the control unit estimates the thickness of the polishing pad 311c after polishing the number (N) of wafers specified in step S1. In steps S12 and S14 to be described later, the number of wafers to which the conditioning is performed once is determined in advance, for example, the conditioning is performed once for polishing two wafers. Therefore, it is possible to calculate how many times the conditioning has been performed after polishing the N wafers. Then, the number of times of conditioning, the currently set conditioning time (conditioning time set latest in steps S10, S19, S30), and the latest average cutting rate (obtained in steps S8, S18, S28). (The latest one of the average cutting rates), the predicted value of the thickness of the polishing pad 311c after polishing N wafers in step S1 can be obtained.
[0094]
Next, the control unit determines whether or not the thickness of the polishing pad 311c predicted in step S11 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 management value d1, the life of the polishing pad 311c does not end even if N wafers are polished, and the process proceeds to step S12.
[0095]
On the other hand, if the thickness of the polishing pad 311c predicted in step S11 is smaller than the minimum management value d1, the life of the polishing pad 311c is exhausted halfway through polishing N wafers, and the process proceeds to step S13. . In step S13, the control unit obtains a maximum value M of the polishing pad 311c, which is estimated when a certain number of wafers are polished and the thickness of the polishing pad 311c is not thinner than the minimum management value d1. The maximum value M is obtained by calculating the predicted value of the polishing pad 311c for each wafer under the condition of M <N, similarly to the calculation for the N wafers in step S11, and comparing it with the minimum management value d1. In, you can ask. Then, the control unit resets the number of wafers to be polished in the actual series of polishing from the number N specified in step S1 to the number M (step S13), and proceeds to step S14.
[0096]
In step S12, the control unit causes each unit to perform the operation described in the flow of wafers described above, thereby polishing a series of N wafers (that is, automatically and continuously polishing the N wafers). When the series of polishing is completed, the process proceeds to step S15. In this example, when the series of polishing is completed, the N unprocessed wafers Wd set in the cassette C1 are stored in the cassette C4 as N processed wafers Wp, respectively.
[0097]
In step S14, the control unit polishes the M wafers in series according to the setting of M wafers in step S13 and causes each unit to perform the operation described in the flow of the wafer described above (that is, the M wafers are polished). The polishing is automatically and continuously performed). When the series of polishing is completed, the process proceeds to step S15. In this example, when the series of polishing is completed, the M unprocessed wafers Wd set in the cassette C1 are stored in the cassette C4 as M processed wafers Wp, respectively.
[0098]
In addition, the control unit not only polishes the wafer with the polishing pad 311c during the series of polishing in steps S12 and S14, but also sets a predetermined number of polishing pads 311c (for example, two, of course, may be one). The control unit swings the polishing arm 311 to move the polishing head 311a above the pad conditioning device 317, and lowers the polishing head 311a while polishing the wafer. The polishing pad 311c is conditioned by rotating the head 311a and the conditioner holding member 317c to rotate them relative to each other. The conditioning in steps S12 and S14 is performed in accordance with the currently set conditioning time (the latest setting time in steps S10, S19 and S30). In the present embodiment, 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. However, the present invention is not limited to this.
[0099]
In step S15, the control unit causes the pad thickness measuring device 319 to measure the thickness of the polishing pad 311c, as in step S2. Next, similarly to step S3, the control unit determines whether the pad thickness measured in step S15 is equal to or greater than a predetermined minimum management 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 S16). If it is thinner than the minimum management value d1, the process proceeds to step S4, whereas if it is not less than the minimum management value d1, the process proceeds to step S17.
[0100]
In step S17, the control unit determines the difference between the pad thickness measured in step S15 and the pad thickness measured in step S3 in step 12 or step S14 (which step has reached step S17. ), The average cutting rate of the polishing pad 311c in the series of polishing is calculated.
[0101]
Next, the control unit determines whether or not the life of the conditioner 317b has expired by determining whether or not the average cutting rate calculated in step S17 is equal to or greater than a minimum management value R1 that determines the life of the conditioner 317b. Is determined (step S18).
[0102]
If it is determined in step S18 that the value is equal to or more than the minimum management value R1 (that is, the life of the conditioner 317b has not expired), each time the polishing pad 311c is used in the next series of polishing (steps S12 and S14). A conditioning time at which the amount of cutting of the polishing pad 311c by the conditioning becomes a predetermined value is obtained from the average cutting rate calculated in step S8, and this conditioning time (one time) is determined at the time of conditioning in the next series of polishing. The conditioning time is reset in the internal memory of the control unit (step S19). Then, the process returns to step S1.
[0103]
If it is determined in steps S9 and S18 that the current value is equal to or less than the minimum management value R1 (that is, the life of the conditioner 317b has expired), the control unit issues an alarm to the above-described alarm unit indicating that the conditioner 317b should be replaced. Is generated by an operator or the like (step S20). Thereafter, the control unit waits for the conditioner 317b to be replaced in step S21, and when the conditioner 317b is replaced, causes the pad thickness measuring device 319 to measure the thickness of the polishing pad 311c as in step S2. (Step S22). Note that the control unit may know the replacement of the conditioner 317b by a signal from a replacement detection sensor (not shown) of the conditioner 317b. It may be known by a predetermined operation or the like.
[0104]
Next, as in step S3, the control unit determines whether the pad thickness measured in step S22 is equal to or greater than a predetermined minimum management value d1 that determines the life of the polishing pad 311c. Then, it is determined whether the life of the polishing pad 311c has expired (step S23). If it is thinner than the minimum management value d1, the process proceeds to step S24, while if it is equal to or more than the minimum management value d1, the process proceeds to step S26.
[0105]
In step S24, the control unit causes the pad replacement device 318 to replace the polishing pad 311c with a new polishing pad, as in step S4. Next, the control unit causes the thickness of the polishing pad 311c to be measured (Step S25), and then proceeds to Step S26.
[0106]
In step S26, the control unit causes the conditioning device 317 to perform break-in conditioning on the polishing pad 311c, as in step S6. The process in step S26 can be said to be the original break-in conditioning when the process proceeds from step S25 to step S26, but the operation is completely the same when the process proceeds from YES in step S23 to step S26. This is a preparatory operation for determining whether the new conditioner 317b is good or not, instead of the original break-in conditioning (initial conditioning of the polishing pad 311c).
[0107]
Next, the control unit causes the thickness of the polishing pad 311c to be measured (Step S27). Next, the control unit determines the difference between the pad thickness measured in step S25 or step S22 (this depends on whether step S25 has been reached via steps S24 and S25) and the pad thickness measured in step S27. Is divided by the conditioning time of the break-in conditioning performed in step 26 to calculate the average cutting rate of the polishing pad 311c in step S26 (step S28).
[0108]
Thereafter, the control unit determines whether the average cutting rate in step S28 is equal to or more than the minimum management value R1 and equal to or less than a predetermined maximum management value R2, thereby determining whether the conditioner 317b is good or bad. A determination is made (step S29). If it is not within the range (if the conditioner 317b is defective), the process returns to step S20. On the other hand, if it is within the range (if the conditioner 317b is good), the process proceeds to step S30.
[0109]
In step S30, the control unit sets a conditioning time such that a cutting amount of the polishing pad 311c by a single conditioning of the polishing pad 311c performed in the next series of polishing (steps S12 and S14) becomes a predetermined value in step S28. The conditioning time (one time) is obtained from the average cutting rate calculated in the above, and is reset in the internal memory of the control unit as the conditioning time at the time of conditioning in the next series of polishing. Then, the process returns to step S1.
[0110]
In the above description of the operation, it has been described that only the first polishing stage 310 exists as the polishing stage. However, in the actual operation in consideration of the second polishing stage 320 and the third polishing stage 330, the same operation as the operation of the first polishing stage 310 is performed for each of the polishing stages 320 and 330. The operation is performed in cooperation with the determination and the processing. For example, after the determination in step S3 is individually performed for the thickness of the polishing pad of each polishing head, the thickness of the polishing pad is the minimum management value for all polishing heads (may be different for each polishing head). Only when the above is the case, the process proceeds to step S11. In other cases, the series polishing is not performed. Further, the number of wafers that are actually polished in a series is determined according to the determination results of steps S11 and S13 for the polishing head of each polishing stage.
[0111]
According to the present embodiment, the thickness of polishing pad 311c is measured in steps S2, S15, and S22, and in steps S3, S16, and S23, if the measured thickness is smaller than predetermined value d1, It is determined that the life 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 accurately polished, and it is possible to prevent a situation in which it is determined that the life of the polishing pad has expired quite early, and the frequency of replacement of the polishing pad can be reduced. Reduce.
[0112]
Further, according to the present embodiment, the average cutting rate of polishing pad 311c is calculated in steps S17 and S8, and when the average cutting rate is lower than predetermined value R1 in steps S18 and S9, the life of conditioner 317b is reduced. It is determined that the condition has run out, and the conditioner 317b 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 appropriately conditioned, and thus the wafer can be polished with high accuracy. Further, it is possible to prevent a situation in which the life of the conditioner is determined to be expired quite early, and the frequency of replacement of the conditioner can be reduced. Running costs are reduced because less is required.
[0113]
Further, according to the present embodiment, when a new conditioner is mounted on the pad conditioning device, predetermined conditioning is performed in step S26, and pad thicknesses are measured in steps S22 and S27 before and after the conditioning, and the measurement is performed. Based on the result, the 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, it is determined that the new conditioner is defective, and step S20 is performed. . Therefore, according to the present embodiment, the polishing pad can be conditioned (conditioning for polishing) with the conditioner having an appropriate cutting ability, so that the polishing pad can exhibit desired polishing characteristics. The wafer can be accurately polished.
[0114]
Furthermore, according to the present embodiment, the average cutting rate of the polishing pad calculated in steps S18, S9, and S29 is changed in steps S19, S9, and S29 to the condition for conditioning in the next series of polishing (the present embodiment). In the form of the above, the conditioning time is, but is not necessarily limited to, the feedback. Therefore, even if the conditioning surface of the conditioner is gradually worn, the effect is greatly reduced, The condition of the polishing surface of the polishing pad after the conditioning is substantially constant for each wafer, and thus a large number of wafers can be stably and accurately polished.
[0115]
Further, according to the present embodiment, steps S11 and S13 are performed to prevent a situation in which the life of the polishing pad is exhausted in the middle of a series of polishing. Therefore, also from this point, a large number of wafers can be polished stably and accurately.
[0116]
In the above embodiment, the pad exchange devices 318, 328, 338 are provided, but in the present invention, these are not necessarily required. If there is no pad exchange device 318, 328, 338, for example, an alarm to the effect that the polishing pad should be exchanged may be issued to the operator in step S4. In the above embodiment, the conditioner is replaced manually. However, a conditioner replacement device for automatically replacing the conditioner may be provided. In this case, instead of generating an alarm in step S20, the conditioner may be replaced by the conditioner replacement device.
[0117]
In addition, in the present invention, in addition to performing precise polishing control in the Cu-CMP process, for example, in addition to wafer processing such as an interlayer insulating film processing process or an STI process, a quartz substrate, a glass substrate, a ceramic substrate, or the like The same can be applied to the processing process described above.
[0118]
Furthermore, the polishing apparatus 1 according to the present embodiment 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 parts. However, the present invention is not limited to this. For example, a configuration in which polishing is performed with two stages of polishing stages, or a configuration in which four or more stages of polishing stages are provided may be employed.
[0119]
[Second embodiment]
[0120]
Next, an embodiment of a method for manufacturing a semiconductor device according to the present invention will be described. FIG. 6 is a flowchart showing a semiconductor device manufacturing process. After starting the semiconductor device manufacturing process, first, in step S200, an appropriate processing step is selected from the following steps S201 to S204. According to the selection, the process proceeds to any of steps S201 to S204.
[0121]
Step S201 is an oxidation step of oxidizing the surface of the silicon wafer. Step S202 is a CVD step of forming an insulating film on the surface of the silicon wafer 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.
[0122]
After the CVD step (S202) or the electrode forming step (S203), the process proceeds to step S209, and it is determined whether a CMP step is performed. If not, the process proceeds to step S206; otherwise, the process proceeds to step S205. Step S205 is a CMP step in which the polishing apparatus according to the present invention is used to planarize an interlayer insulating film, form a damascene by polishing a metal film on the surface of a semiconductor device, and the like. .
[0123]
After the CMP step (S205) or the oxidation step (S201), the process proceeds to step S206. Step S206 is a photolithography step. In this step, a resist is applied to the silicon wafer, a circuit pattern is printed on the silicon wafer by exposure using an exposure device, and development of the exposed silicon wafer is performed. Further, the next step S207 is an etching step of removing portions other than the developed resist image by etching, removing the resist, and removing unnecessary resist after etching.
[0124]
Next, in 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.
[0125]
In the semiconductor device manufacturing method according to the present invention, since the polishing apparatus according to the present invention is used in the CMP step, the processing accuracy of the CMP step is improved without using a polishing pad or a conditioner whose life has expired, Running costs can be reduced. Thereby, it is possible to manufacture a semiconductor device having less manufacturing variation at low cost as compared with the conventional semiconductor device manufacturing method. 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 may be used in a CMP step of a semiconductor device manufacturing process other than the semiconductor device manufacturing process.
[0126]
The embodiments of the present invention and the modifications thereof have been described above, but the present invention is not limited to these.
[0127]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a method for determining the life of a polishing pad or a conditioner capable of accurately determining the life of a polishing pad or a conditioner.
[0128]
Further, according to the present invention, it is possible to provide a conditioner quality determination method that can appropriately determine the quality of a new conditioner.
[0129]
Furthermore, according to the present invention, it is possible to provide a method for conditioning a polishing pad, which can polish each object to be polished in the same manner.
[0130]
Further, according to the present invention, it is possible to provide a polishing apparatus capable of reducing running costs.
[0131]
Further, the present invention can provide a polishing apparatus that can polish each object to be polished in the same manner.
[0132]
Furthermore, the present invention can provide a semiconductor device manufacturing method and a low-cost semiconductor device that can manufacture a semiconductor device at a lower cost than conventional semiconductor device manufacturing methods.
[Brief description of the drawings]
FIG. 1 is a schematic top view schematically showing a polishing apparatus according to a 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. 1;
FIG. 3 is a schematic cross-sectional view schematically showing main components located on a first polishing stage in the polishing apparatus shown in FIG. 1 when viewed from a 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. 1;
FIG. 6 is a flowchart showing a semiconductor device manufacturing process.
[Explanation of symbols]
V1, V2, V3, V4 Chuck
W wafer (Wd unprocessed wafer, Wp processed wafer)
1 Polishing device
310, 320, 330 Polishing stage
311,321,331 Polishing arm
311a Polishing head
311c polishing pad
317,327,337 Pad conditioning device
318,328,338 Pad exchange device
319,329,339 Pad thickness measuring device
340 index table
350 transfer stage

Claims (13)

A life determining method for determining the life of a polishing pad used for polishing an object to be polished, comprising: measuring a thickness of the polishing pad; A method for determining the life of a polishing pad, comprising determining that the life of the pad has expired. 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,
Conditioning the polishing pad with a cumulative conditioning time using the conditioner,
Before and after conditioning of the cumulative conditioning time, measure the thickness of the polishing pad,
Based on the thickness of the polishing pad measured before and after the conditioning of the cumulative conditioning time, to determine the average cutting rate during the cumulative conditioning time of the polishing pad,
When the average cutting rate is lower than a predetermined value, it is determined that the life of the conditioner has expired. A good or bad judgment method for judging the quality of a new conditioner used for conditioning of a polishing pad used for polishing an object to be polished, wherein the polishing pad is subjected to a cumulative conditioning time conditioning using the new conditioner,
Before and after conditioning of the cumulative conditioning time, measure the thickness of the polishing pad,
Based on the thickness of the polishing pad measured before and after the conditioning of the cumulative conditioning time, to determine the average cutting rate during the cumulative conditioning time of the polishing pad,
When the average cutting rate is outside a predetermined range, it is determined that the new conditioner is defective. A conditioning method for conditioning a polishing pad used for polishing an object to be polished with a conditioner,
Conditioning the polishing pad at least once under predetermined conditions using the conditioner,
Before and after the one or more conditioning, measure the thickness of the polishing pad,
Based on the thickness of the polishing pad measured before and after the one or more conditioning, determine the average cutting rate in the one or more conditioning of the polishing pad,
Based on the average cutting rate, set a conditioning condition at the time of the next conditioning of the one or more conditioning,
The conditioning method for a polishing pad, wherein the next round of conditioning is performed according to the set conditioning conditions. The polishing pad conditioning method according to claim 4, wherein the conditioning condition is a conditioning time. While applying a load between the polishing pad and the object to be polished, by relatively moving the polishing pad and the object to be polished, in a polishing apparatus for polishing the object to be polished,
A measuring unit for measuring the thickness of the polishing pad,
When the thickness of the polishing pad measured by the measuring unit is smaller than a predetermined value, an alarm is generated to notify that the polishing pad should be replaced with a new polishing pad, or the polishing pad is automatically replaced with a new polishing pad. Means to exchange;
A polishing apparatus comprising: While applying a load between the polishing pad and the object to be polished, by relatively moving the polishing pad and the object to be polished, in a polishing apparatus for polishing the object to be polished,
A conditioning unit having a conditioner and conditioning the polishing pad with the conditioner;
A measuring unit that measures the thickness of the polishing pad at a first timing and a second timing thereafter;
The polishing pad by the conditioner in a period from the first timing to the second timing based on the thickness measured at the first timing and the thickness measured at the second timing A calculating unit for calculating an average cutting rate during the cumulative conditioning time of
Means for alerting that the conditioner should be replaced with a new conditioner when the average cutting rate is lower than a predetermined value or automatically replacing the conditioner with a new conditioner;
A polishing apparatus comprising: While applying a load between the polishing pad and the object to be polished, by relatively moving the polishing pad and the object to be polished, in a polishing apparatus for polishing the object to be polished,
A conditioning unit having a conditioner and conditioning the polishing pad with the conditioner;
A first timing before a new conditioner is mounted on the conditioning unit and the new conditioner is used for conditioning the polishing pad, and thereafter after conditioning the polishing pad using the new conditioner. At a second timing, a measuring unit for measuring the thickness of the polishing pad,
The polishing pad by the conditioner in a period from the first timing to the second timing based on the thickness measured at the first timing and the thickness measured at the second timing A calculating unit for calculating an average cutting rate during the cumulative conditioning time of
Means for alerting that the conditioner should be replaced with a newer conditioner or automatically replacing the conditioner with a newer conditioner when the average cutting rate is outside a predetermined range;
A polishing apparatus comprising: While applying a load between the polishing pad and the object to be polished, by relatively moving the polishing pad and the object to be polished, in a polishing apparatus for polishing the object to be polished,
A conditioning unit having a conditioner and conditioning the polishing pad with the conditioner;
A measuring unit that measures the thickness of the polishing pad at a first timing and a second timing thereafter;
The polishing pad by the conditioner in a period from the first timing to the second timing based on the thickness measured at the first timing and the thickness measured at the second timing Means for determining an average cutting rate during the cumulative conditioning time of
Based on the average cutting rate, a conditioning condition setting unit that sets a conditioning condition of the next conditioning after the period of the polishing pad,
A polishing apparatus comprising: The polishing apparatus according to claim 9, wherein the conditioning condition is a conditioning time. While applying a load between the polishing pad and the object to be polished, by relatively moving the polishing pad and the object to be polished, in a polishing apparatus for polishing the object to be polished,
A conditioning unit having a conditioner, wherein the polishing pad is conditioned by the conditioner, each time the polishing pad polishes a predetermined number of the objects to be polished,
A measuring unit that measures the thickness of the polishing pad at a first timing and a second timing thereafter;
Based on the thickness measured at the first timing and the thickness measured at the second timing, the number of the objects to be polished by the polishing pad after the second timing, A means for limiting the thickness of the polishing pad, which is estimated when the object to be polished is assumed to be polished, to a number not less than a predetermined value, and
A polishing apparatus comprising: A method for manufacturing a semiconductor device, comprising a step of flattening a surface of a semiconductor wafer using the polishing apparatus according to claim 6. A semiconductor device manufactured by the semiconductor device manufacturing method according to claim 12.

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