JP4259048B2 - Conditioner lifetime determination method, conditioner determination method using the same, polishing apparatus, and semiconductor device manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polishing technique, and more particularly to a polishing pad life determination method, a conditioner life determination method, a conditioner quality determination 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 that polishes an object to be polished by relatively moving the polishing pad and the object to be polished while applying a load between the polishing pad and the object to be polished.
[0003]
As such a polishing apparatus, for example, a polishing apparatus that performs chemical mechanical polishing (Chemical Mechanical Polishing or Chemical Mechanical Planarization, hereinafter referred to as CMP) for global planarization of a surface of a semiconductor device wafer or the like is given. be able to. CMP is a process of removing irregularities on the surface of a wafer by using both physical polishing and chemical action (polishing agent, dissolving with a solution) to remove the surface irregularities of the wafer. Thus, the polishing is advanced by pressurizing and relatively moving the wafer surface, and uniform polishing within the wafer surface becomes possible.
[0004]
In such a polishing apparatus, the polishing surface of the polishing pad deteriorates as clogging progresses according to the polishing time, so that good processing is continued by performing regular conditioning (also called dressing). Maintenance.
[0005]
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. As the conditioner, for example, a tool in which abrasive grains such as diamond particles are distributed over the entire 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 the consumption due to polishing of an object to be polished such as a wafer and the consumption (cutting) due to the conditioning, and eventually the desired polishing characteristics cannot be obtained, resulting in a shortened life. run out. For this reason, it is necessary to replace the polishing pad with a new polishing pad. Therefore, conventionally, the life of the polishing pad is determined by the accumulated time of the polishing pad, the accumulated time of the conditioning, the number of objects to be polished, and the number of times of conditioning. The polishing pad was replaced with a new one. Note that 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]
Moreover, the conditioning apparatus which performs the said conditioning is generally set as the structure provided with the said conditioner and the holding | maintenance part holding this. The conditioning surface of the conditioner is also consumed due to the conditioning of the polishing pad, and eventually the desired conditioning characteristics cannot be obtained and the life is exhausted. Therefore, conventionally, the life of the conditioner is determined based on the accumulated time and number of times of conditioning by the conditioner, and when it is determined that the life is exhausted, the conditioner is replaced with a new one. Then, the new conditioner has always been used for conditioning the polishing pad without performing a special check, assuming that it has the desired conditioning characteristics.
[0008]
Further, conventionally, 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 has been performed under the same conditioning conditions every time.
[0009]
[Problems to be solved by the invention]
However, in the conventional method for determining the life of the polishing pad, the life of the polishing pad is determined based on the accumulated time and number of times of polishing and conditioning, and thus the life of the polishing pad cannot be accurately determined. Therefore, in actuality, it is determined that the life of the polishing pad has been exhausted fairly early, even though the desired polishing characteristics can still be obtained sufficiently, and replaced with a new polishing pad in anticipation of a considerable margin. Was. Therefore, the running cost of the polishing apparatus has increased. If it is not determined that the life of the polishing pad has been exhausted early in anticipation of sufficient margin, the life of the polishing pad cannot be accurately determined, so that the polishing pad can obtain desired polishing characteristics. Despite being lost, 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 conditioner life determination method, since the conditioner life is determined based on the cumulative time and number of times of conditioning, the life of the conditioner cannot be accurately determined. Therefore, in practice, it is determined that the conditioner has reached the end of its life fairly early, despite the fact that the desired conditioning characteristics can still be obtained sufficiently in actuality. I was exchanging. Therefore, the running cost of the polishing apparatus has increased. If it is not determined that the conditioner has reached the end of its life early in anticipation of sufficient margin, the conditioner will not be able to accurately determine the endurance of the conditioner. In spite of the loss, the polishing pad is conditioned, and as a result, the polishing pad cannot exhibit the desired polishing characteristics. As a result, the object to be polished cannot be accurately polished, which is fatal. Invite results.
[0011]
Furthermore, it has been found that new conditioners do not always have the desired conditioning characteristics. For example, in the case of a new conditioner, the cutting ability by abrasive grains is too high, and the polishing surface of the polishing pad becomes too rough beyond the stage of recovering clogging of the polishing pad, etc. Has been found to fail to exhibit the desired polishing characteristics. Therefore, if the new conditioner is used for the conditioning of the polishing pad without checking at all as in the conventional case, the polishing pad cannot exhibit the desired polishing characteristics, and as a result, the object to be polished can be polished with high accuracy. There was a risk that it could not be fatal. However, heretofore, there has been no effective method for judging the quality of a new conditioner.
[0012]
Conventionally, as described above, 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 has been performed under the same conditioning conditions every time. However, since the conditioning surface of the conditioner gradually wears out, the state 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.
[0013]
The present invention has been made in view of such circumstances, and an object thereof is to provide a polishing pad life determination method capable of accurately determining the life of a polishing pad.
[0014]
Another object of the present invention is to provide a conditioner lifetime determination method that can accurately determine the lifetime of a conditioner.
[0015]
Furthermore, an object of the present invention is to provide a conditioner quality determination method capable of appropriately determining the quality condition of a new conditioner.
[0016]
Furthermore, an object of the present invention is to provide a conditioning method for a polishing pad that can be similarly polished for each object to be polished.
[0017]
Another object of the present invention is to provide a polishing apparatus that can reduce running costs.
[0018]
Furthermore, an object of this invention is to provide the grinding | polishing apparatus which can grind | polish similarly about each to-be-polished object.
[0019]
Still another object of the present invention is to 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.
[0020]
[Means for Solving the Problems]
In order to solve the above-described problem, a polishing pad life determination method according to the first aspect of the present invention is a life determination method for determining the life of a polishing pad used for polishing an object to be polished, the thickness of the polishing pad When the measured thickness of the polishing pad is thinner than a predetermined value, it is determined that the life of the polishing pad has been exhausted.
[0021]
A conditioner lifetime determination method according to a second aspect of the present invention is a lifetime determination method for determining the lifetime 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, measuring the thickness of the polishing pad before and after conditioning of the cumulative conditioning time, and based on the thickness of the polishing pad measured before and after 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 been exhausted.
[0022]
A conditioner pass / fail judgment method according to a third aspect of the present invention is a pass / fail judgment method for judging pass / fail of a new conditioner used for conditioning a polishing pad used for polishing an object to be polished. Conditioning the cumulative conditioning time using the new conditioner, measuring the thickness of the polishing pad before and after conditioning of the cumulative conditioning time, and measuring the thickness of the polishing pad before and after conditioning of the cumulative conditioning time The average cutting rate of the polishing pad during the cumulative conditioning time is obtained, and when the average cutting rate is outside a predetermined range, it is determined that the new conditioner is defective.
[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 used under a predetermined condition using the conditioner. Conditioning one or more times, measuring the thickness of the polishing pad before and after the one or more times of conditioning, and based on the thickness of the polishing pad measured before and after the one or more times of conditioning, An average cutting rate in the one or more conditioning is obtained, and based on the average cutting rate, a conditioning condition at the next conditioning of the one or more conditioning is set, and the conditioning of the next round is performed. Condition set above It is performed in accordance with grayed conditions.
[0024]
The polishing pad conditioning method according to the fifth aspect of the present invention is the fourth aspect, wherein the conditioning condition is a conditioning time.
[0025]
A polishing apparatus according to a sixth aspect of the present invention polishes the object to be polished by relatively moving the polishing pad and the object to be polished while applying a load between the polishing pad and the object to be polished. In the polishing apparatus, a measurement unit that measures the thickness of the polishing pad, and an alarm that the polishing pad should be replaced with a new polishing pad when the thickness of the polishing pad measured by the measurement unit is less 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 to be polished by relatively moving the polishing pad and the object to be polished while applying a load between the polishing pad and the object to be polished. In the polishing apparatus, a conditioning unit having a conditioner for conditioning the polishing pad with the conditioner, a measurement unit for measuring the thickness of the polishing pad at a first timing and a second timing thereafter, and the first Accumulation of the polishing pad by the conditioner within the period from the first timing to the second timing based on the thickness measured at the timing of 1 and the thickness measured at the second timing A calculation unit for calculating an average cutting rate during a conditioning time; and 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 to be polished by relatively moving the polishing pad and the object to be polished while applying a load between the polishing pad and the object to be polished. In the polishing apparatus, a conditioning unit having a conditioner and conditioning the polishing pad with the conditioner, and a new conditioner mounted on the conditioning unit and the new conditioner before being used for conditioning the polishing pad. 1 at the second timing after the conditioning of the polishing pad using the new conditioner, and a measurement unit for measuring the thickness of the polishing pad, and the measurement at the first timing. Based on the thickness and the thickness measured at the second timing, The calculation unit that calculates an average cutting rate during the cumulative conditioning time of the polishing pad by the conditioner within a period from the first timing to the second timing, and the average cutting rate is outside a predetermined range. And a means for generating an alarm that the conditioner should be replaced with a new conditioner or automatically replacing the conditioner with a new conditioner.
[0028]
In the polishing apparatus according to the ninth aspect, the polishing object is polished by relatively moving the polishing pad and the object to be polished while applying a load between the polishing pad and the object to be polished. A polishing unit that includes a conditioner for conditioning the polishing pad with the conditioner, a measurement unit that measures the thickness of the polishing pad at a first timing and a second timing thereafter, and Based on the thickness measured at the first timing and the thickness measured at the second timing, the condition of the polishing pad by the conditioner within the period from the first timing to the second timing is determined. Means for determining an average cutting rate during cumulative conditioning time, and based on the average cutting rate, the polishing pad 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 to be polished by relatively moving the polishing pad and the object to be polished while applying a load between the polishing pad and the object to be polished. The polishing apparatus includes a conditioner, a conditioning unit that performs conditioning each time the polishing pad is polished by the conditioner, and a predetermined number of the objects to be polished by the polishing pad, and a first timing and a subsequent first timing. After the second timing, based on the measuring unit that measures the thickness of the polishing pad at the timing of 2, the thickness measured at the first timing, and the thickness measured at the second timing When the number of the objects to be polished by the polishing pad is assumed to have been polished, the number of the objects to be polished is predetermined. It 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 a step of planarizing the surface of a semiconductor wafer using the polishing apparatus according to any 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]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a polishing pad life determination method, a conditioner life determination method, a conditioner pass / fail determination 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. To 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 how the wafer is processed by 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. For convenience of drawing, a polishing state monitoring device 50a described later is omitted in FIG.
[0036]
The polishing apparatus 1 according to the present embodiment is an example of a CMP apparatus that precisely polishes 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 is mainly composed of a cassette index part 100, a wafer cleaning part 200, and a polishing part 300, and each part is partitioned to constitute a clean chamber. An automatic opening / closing shutter may be provided between the chambers.
[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 cleaning machine temporary storage table of the cleaning unit 200 by removing unprocessed wafers from the cassette. And a first transfer robot 150 that stores processed wafers that have been transferred into the 211 and cleaned by the wafer cleaning unit 200 after polishing.
[0039]
The first transfer robot 150 is an articulated arm type robot having two articulated arms 153a and 153b. A base 151, a swivel base 152 that can be horizontally swung and raised and lowered on the base 151, and a swivel base 152 are provided. Two articulated arms 153a and 153b attached on the top, and an A arm 155a and a B arm 155b (B arm 155b is attached to the distal ends of the articulated arms 153a and 153b so as to be extendable with respect to each arm). It is arranged offset below the A arm 155a and is positioned so as to overlap in the vertical direction in FIGS. A holding portion for mounting and holding the wafer by suction is formed at the tip of the A arm 155a and the B arm 155b. In addition, the base 151 is provided with a linear moving device that can move horizontally along a linear guide 160 disposed on the floor surface.
[0040]
For this reason, the first transfer robot 150 moves along the linear guide 160 to the front of the target cassette, horizontally swings and lifts the swivel base 152, and moves the A arm 155a or B arm 155b to the target slot height. Then, the articulated arm 153a and the A arm 155a, or the articulated arm 153b and the B arm 155b are operated to suck the unprocessed wafer in the target slot with the holding portion at the tip of the A arm 155a or the B arm 155b. It can be held and taken out, or the processed wafer can be stored in the target slot.
[0041]
Note that these two pairs of arms 155a and 155b 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 applications. In the illustrated polishing apparatus, the unprocessed wafer is set out from the cassette by the lower B arm 155b, and the cleaned processed wafer is stored in the cassette by the upper A arm 155a. Yes.
[0042]
The wafer cleaning unit 200 has a four chamber configuration of a first cleaning chamber 210, a second cleaning chamber 220, a third cleaning chamber 230, and a drying chamber 240, and a polished wafer is transferred from the first cleaning chamber 210 to the second cleaning chamber. 220 → third cleaning chamber 230 → drying chamber 240 are sequentially sent to remove and wash slurry, polishing processing liquid, polishing wear powder, and the like which are adhered to the polishing processing unit 300. For example, double-sided cleaning with a rotating brush in the first cleaning chamber 210, surface pencil cleaning with ultrasonic vibration in the second cleaning chamber 220, spinner cleaning with pure water in the third cleaning chamber 230, and nitrogen atmosphere in the drying chamber 240 The drying process is performed. An unprocessed wafer before polishing is passed through the wafer cleaning unit 200 from the cassette index unit 100 via the cleaning machine temporary placement table 211 and carried into the wafer polishing unit 300 without passing through the above-described cleaning process.
[0043]
The polishing unit 300 is provided so as to surround the index table 340 from the outer periphery in correspondence with the positioning stop position of the index table 340 and the index table 340 which is divided into four parts and rotated and fed every 90 degrees by the operation of a stepping motor or the like. The first polishing stage 310, the second polishing stage 320, the third polishing stage 330, and the index table 340 are loaded with a raw wafer and a processed stage 350 to carry out the processed wafer. The polishing stage is sometimes 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 attracting and holding the wafer from the back surface are disposed on the upper surface of the table, and each chuck V1 to V4 is placed on the index table 340 in a horizontal plane ( 1 in a plane parallel to the paper surface in FIG. 1 and is freely mounted at high speed and stopped and held by driving means such as an electric motor or an air motor provided in the index table 340. . The diameters of the chucks V1 to V4 are formed to be slightly smaller than the wafer diameter, and are configured to be able to grip the outer peripheral edge of the wafer held by the chucks V1 to V4.
[0045]
Each of the three polishing stages of the first polishing stage 310, the second polishing stage 320, and the third polishing stage 330 has a polishing arm 311 that can swing in the horizontal direction and move up and down in the vertical direction with respect to the index table 340. , 321, 331 are provided.
[0046]
As shown in FIG. 3, a polishing head 311a is attached to the tip of the polishing arm 311 so as to hang down from the polishing arm 311 and rotate at high speed in a horizontal plane. Has a polishing pad 311c as a polishing body for flat polishing. In the present embodiment, the polishing pad 311c is attached to the attachment plate 311b, and the attachment plate 311b is held by vacuum suction on the polishing head 311a. Every one is automatically exchanged. As such a polishing head 311a and a pad exchange device 318, for example, those disclosed in Japanese Patent Application Laid-Open No. 2001-148361 can be employed. Although not shown in the drawings, a polishing head that is suspended from the polishing arms 321 and 331 and is rotatable at high speed in a horizontal plane is attached to the tip of each polishing arm 321 and 331, and a wafer and And a polishing pad as a polishing body for flatly polishing the wafer by relative rotation.
[0047]
As shown in FIGS. 1 and 2, each polishing stage 310, 320, 330 has a pad thickness measuring device 319, 329, 339 for measuring the thickness of the polishing pad, and pad conditioning for conditioning the surface of the polishing pad. Devices 317, 327, and 337 and pad changing devices 318, 328, and 338 for automatically changing the polishing pad are attached.
[0048]
In the present embodiment, as shown in FIG. 3, a commercially available contact stylus 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 and reaches its height. Accordingly, the thickness distribution in the radial direction of the polishing pad 311c can be measured by sliding the stylus 319a in the radial direction of the polishing pad 311c. In the present embodiment, since the average value (maximum value or minimum value) of the radial thickness distribution is adopted as the thickness of the polishing pad 311c, the radial thickness distribution of the polishing pad 311c is determined. For example, the thickness of only one point on the polishing surface of the polishing pad 311c may be measured. As the pad thickness measuring 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]
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 in which ring-shaped diamond abrasive grains and the like are distributed, and a conditioner 317b. A conditioner holding member 317c that rotates, and a rotation mechanism 317d that rotates 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 and the conditioning surface 317a of the conditioner 317b into contact with each other, applying a load, and rotating them. The pad conditioning devices 327 and 337 are configured in the same manner 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 the operator. However, as in the case of the polishing pad, the conditioner that automatically replaces the conditioner. An exchange device may be provided.
[0050]
The relative positions of the polishing arm and chuck, the pad thickness measuring device, the pad conditioning device, and the pad exchanging device in each of the polishing stages 310, 320, and 330 are defined so as to be positioned on the rocking circumference of the polishing head at the tip of the polishing arm. Has been. Therefore, for example, when polishing is performed 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 relatively rotated and the polishing arm 311 is lowered. As a result, the polishing pad is pressed onto the wafer to perform polishing. Needless to say, an abrasive (slurry) is interposed between the polishing pad and the wafer during polishing. In the final stage of the polishing process, the abrasive on the object to be polished is washed away by a water supply device (not shown), and then drained by rotating the chuck, for example.
[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 rocked every predetermined number of times of polishing (that is, every number of wafers). The pad conditioning device 317 is moved to make adjustments (conditioning) for correcting clogging or unevenness of the polishing pad 311c, and the polishing arm 311 is further swung at a timing described later to make the polishing pad 311c the pad exchange device 318. The polishing pad 311c is automatically replaced by this apparatus.
[0052]
The polishing arm 311 is provided with an arm position detector (not shown) that detects the swing angle position of the arm, and detects the polishing processing position, pad thickness measurement position, conditioning position, and pad replacement position of the polishing arm 311. is doing.
[0053]
Further, as shown in FIG. 1, a polishing state monitor device 50a for optically monitoring the polishing state of the wafer being polished is attached to each polishing stage, and a decrease in film thickness during the polishing process is detected in real time. It is possible. As the polishing state monitoring device 50a, for example, a device disclosed in Japanese Patent Laid-Open No. 2000-40680 can be used. In the present embodiment, the polishing state monitoring device 50a has an arm 61 that extends approximately parallel to the polishing arm of each polishing stage and is swingable in the horizontal direction. The arm 61 incorporates an optical fiber or the like. From the tip of the arm 61, the probe light is locally irradiated onto the wafer being held by the chuck and being polished, and the reflected light from the wafer is received and predetermined. It is led to the place. The arm 61 is configured to swing in synchronization with the polishing arm during the polishing process in order to avoid mechanical interference with the polishing arm. In the present embodiment, the polishing status monitoring device 50a monitors the polishing status 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 in 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 first transfer robot 150 described above, and has two multi-joints that are swingably mounted on a turntable 362 that can be horizontally swung and raised and lowered. 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 in a telescopic manner. The A arm 365a and the B arm 365b are arranged so as to be offset in the vertical direction, and a holding portion for mounting and holding the wafer by suction is formed at the distal ends of the arms 365a and 365b.
[0056]
The third transfer robot 370 includes a swing arm 371 that is swingable in the horizontal direction with respect to the index table 340 and that is vertically movable in the vertical direction, and a horizontal end of the swing arm 371 with respect to the swing arm 371. The rotary arm 372 is pivotally attached, and is composed of an A clamp 375a and a B clamp 375b that are suspended from both ends of the rotary arm 372 and grip the outer peripheral end of the wafer. The A clamp 375a and the B clamp 375b are disposed at the end of the rotation arm at the same distance from the rotation center of the rotation arm 372. Further, the state shown in FIG. 1 shows the standby posture of the third transfer robot 370. Below the A clamp 375a and the B clamp 375b in the drawing, an A temporary placement table 381 on which an unprocessed wafer is placed. And a B temporary placement table 382 on which a polished wafer is placed.
[0057]
Therefore, the A clamp 375a or the B clamp 375b can be moved onto the chuck V1 of the index table 340 by swinging the swing arm 371 of the third transfer robot 370 and further swinging the swing arm 372. In this position, the swing arm 371 can be lowered and the wafer on the chuck can be clamped and received by the A clamp 375a or B clamp 375b, or a new wafer can be placed and held on the chuck.
[0058]
Since the polishing liquid containing slurry is attached to the polished wafer, the arm and clamp for loading the wafer before polishing and the arm and clamp for unloading the polished wafer are provided. Of the A and B arms 365a and 365b offset up and down, the upper A arm 365a is an unloaded wafer loading arm, the lower B arm 365b is an unloading arm, and an A clamp. 375a is defined as a loading clamp, and B clamp 375b is defined as a loading 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 by focusing on the flow of the wafer, omitting the operations related to pad thickness measurement, pad replacement, conditioning, and conditioner replacement. 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 before being polished by the polishing apparatus 1 (referred to as an unprocessed wafer in this specification) is divided into three stages: a first polishing process P1, a second polishing process P2, and a third polishing process P3. A description will be given by taking as an example a case where polishing is performed flat by polishing by CMP. In the following example, the first polishing process P1, the second polishing process P2, and the third polishing process P3 are performed at the first polishing stage 310, the second polishing stage 320, and the third polishing stage 330, respectively. It has become.
[0061]
In the second polishing process P2 and the third polishing process P3, the polishing process is temporarily ended by detecting the polishing end point by the polishing state monitoring device 50a. On the other hand, in this example, the primary polishing process P1 is a pre-stage polishing process of the secondary polishing process P2, and it is not necessary to detect the end point. Therefore, the primary polishing process P1 is performed by time management. The process is terminated at a predetermined polishing time tp1.
[0062]
In FIG. 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 be processed wafers Wp, cleaned by the wafer cleaning unit 200, and then cleaned by the cassette index unit 100. The wafer flow until it is stored in the cassette C4 is shown with 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 including a personal computer (not shown). Performs these operation controls 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 later, and an input device for an operator to give various commands. The alarm unit may generate either a visual alarm or an audible alarm, or may generate both.
[0063]
First, when the polishing apparatus 1 is activated and polishing processing is started, the first transfer robot 150 moves to the position of the cassette C1, and the swivel base 152 is horizontally swung and lifted to move the wafer for the B arm 155b. By moving to the slot height, the articulated arm 153b and the B arm 155b are extended, the unprocessed wafer Wd in the slot is sucked and held by the holding portion at the tip of the B arm 155b, and both the arms are contracted and pulled out. Then, the swivel base 152 is swung 180 degrees toward the wafer cleaning unit 200, and the unprocessed wafer Wd is placed on the cleaning machine temporary placement table 211 provided in the cleaning unit 200.
[0064]
When the unprocessed wafer Wd is placed on the temporary placement table 211, the second transfer robot 360 of the loading stage 350 facing the wafer cleaning chamber 200 operates the swivel table 362 to clean the tip of the A arm 365a. It turns so that it may go to the machine temporary mounting base 211, the articulated arm 363a and the A arm 365a are extended, and the unprocessed wafer Wd on the cleaning machine temporary mounting base 211 is sucked and held by the holding part at the tip of the A arm. When the unprocessed wafer Wd is held, the articulated arm 363a and the A arm 365a are contracted and the swivel base 362 is rotated and reversed, and the articulated arm 363a and the A arm 365a are expanded and operated again. The wafer Wd is placed on the A temporary placement table 381.
[0065]
When the unprocessed wafer Wd is placed on the A temporary placement table 381, the third transfer robot 370 is lowered to hold the unprocessed wafer Wd by the A clamp 375a, and is moved up to a predetermined height after holding. And wait until the positioning of the index table 340 is completed (standby posture). When the positioning 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 moves up after releasing the clamp, swings and swings the swing arm 371 and the swing arm 372, and holds the next unprocessed wafer Wd with the A clamp 375a. Wait until the next index operation at the standby position.
[0066]
Thereafter, the polishing process in the polishing unit 300 is started. The flow until the unprocessed wafer Wd carried into the carry-in stage 350 is carried out from the transfer stage 350 through the first polishing stage 310, the second polishing stage 320, and the third polishing stage 330 is as follows.
[0067]
In the following description, the progress until a single unprocessed wafer Wd is processed at each stage and stored as a processed wafer will be described in time series. New wafers are successively carried in, new processed wafers are carried out each time the index table 340 is rotated, and operations relating to different wafers are simultaneously performed in parallel at each stage.
[0068]
When the unprocessed wafer Wd is sucked and held on the chuck V1 and the third transfer robot 370 is retracted from above the index table 340, the index table 340 is moved 90 degrees clockwise (clockwise) in FIGS. The unprocessed wafer Wd is positioned on the first polishing stage 310 (V4 position in FIGS. 1 and 2). At the same time, the polishing arm 311 is swung to move the polishing head onto the unprocessed wafer Wd.
[0069]
When the index table 340 stops positioning, for example, the polishing head and the chuck V1 are rotated at a high speed in the opposite directions, for example, and the polishing arm 311 is lowered to press the polishing pad at the lower end of the polishing head onto the wafer. Do. During the polishing process, the polishing pad is reciprocated between the rotation center of the wafer and the outer peripheral end while supplying the slurry from the axis of the polishing head, and the polishing arm 311 is swung in a minute range to move the wafer. Uniform flat polishing. In the transfer stage 350, a new unprocessed wafer is transferred onto the chuck V2 by the third transfer robot 370 during the first polishing process.
[0070]
The first polishing process P1 at the first polishing stage 310 is time-controlled as described above, and when the predetermined polishing process time tp1 elapses, the polishing arm 311 is raised to perform the polishing process at 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 at the stage other than the first polishing stage 310 has been completed). Wait for
[0071]
If the index table 340 can be operated, the index table 340 is rotated 90 degrees clockwise again, and the wafer having undergone the first polishing process P1 is moved to the second polishing stage 320 (V3 in FIGS. 1 and 2). Position). At the same time, the polishing arm 321 is swung to move the polishing head onto the wafer. Then, the polishing arm 321 is lowered, and the polishing process (secondary polishing process P2) at the second polishing stage 320 is performed by the same operation as the first polishing process P1.
[0072]
The secondary polishing process P2 at 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 set in advance, the polishing arm 321 is raised to The polishing process is stopped, and cleaning and draining are performed to wash away the abrasive (slurry) on the object to be polished.
[0073]
Next, the 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 has been completed). Wait for it to become.
[0074]
If the index table 340 can be operated, the index table 340 is rotated 90 degrees clockwise again, and the wafer after the second polishing process P2 is positioned on the third polishing stage 330 (V2 position in the drawing). To do. Then, the polishing arm 331 is lowered to perform the polishing process (third polishing process 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 also a so-called end point detection process, like 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 set in advance, the control unit raises the polishing arm 331 to perform the third operation. The polishing process 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 at a stage other than the third polishing stage 330 has been completed). Wait for it to become.
[0077]
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 third polishing process P3 is transferred to the transfer stage 350 (V1 position in FIGS. 1 and 2). Position to. When the index table 340 stops positioning, the third transfer robot 370 swings and swings the swing arm 371 and the swing arm 372 and unloads the processed wafer Wp after the polishing process is completed. The processed wafer Wd is loaded onto the chuck V1 and attracted and held by the chuck V1, and the above operation is repeated.
[0078]
When the processed wafer Wp is placed on the B temporary placement 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 operate the B arm. The processed wafer Wp on the B temporary placement table 382 is sucked and held by the holding unit at the tip, the swivel table 362 is swung, the articulated arm 363b and the B arm 365b are stretched, and the cleaning unit 200 enters the cleaning machine. A processed wafer Wp is placed on 216.
[0079]
In the cleaning unit 200, double-sided cleaning with a rotating brush in the first cleaning chamber 210, surface pencil cleaning with ultrasonic vibration in the second cleaning chamber 220, spinner cleaning with pure water in the third cleaning chamber 230, and in the drying chamber 240 A drying process is performed in a nitrogen atmosphere. The finished product wafer thus cleaned is taken out from 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 wafers Wd set in the cassette C1 of the cassette index unit 100 are sequentially polished by the polishing unit 300 to be processed wafers Wp, cleaned by the wafer cleaning unit 200, and cassette C4 of the cassette index unit 100. The flow of the wafer until it is housed in has been described.
[0081]
In the polishing apparatus 1 according to the present embodiment, the control unit automatically and continuously controls a plurality of wafers (for example, a plurality of wafers accommodated in the cassette C1) from an operator via an input device (not shown). When receiving a command to start polishing (herein referred to as “series polishing”), basically, for each of these wafers, operations on different wafers are performed simultaneously in each stage. Processing according to the wafer flow described above is performed.
[0082]
Next, focusing on the operations related to pad thickness measurement, pad replacement, conditioning, and conditioner replacement, which are characteristic operations of the present embodiment, focusing on one polishing stage 310, flowcharts shown in FIGS. The operation of the polishing apparatus 1 will be described with reference to FIG. Please also refer to FIGS.
[0083]
In the following description, in order to facilitate understanding, it is assumed that only the first polishing stage 310 exists as the polishing stage. The actual operation considering 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 of polishing has been obtained from the input device (step S1), and waits until it is obtained if the start command is not obtained. This command specifies how many wafers are to be polished continuously. Here, it is assumed that N wafers are designated to be polished continuously.
[0085]
When a command for starting a series of polishings is obtained, the control unit swings the polishing arm 311 to move the polishing head 311a above the pad thickness measuring device 319 and causes the pad thickness measuring device 319 to measure the thickness of the polishing pad 311c. (Step S2). As described above, the thickness value may be any one of an average value, a maximum value, a minimum value, and a certain point value of the thickness distribution in the radial direction, but an average value is preferable.
[0086]
Next, the controller determines the life of the polishing pad 311c by determining whether or not 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. It is determined whether or not all are exhausted (step S3).
[0087]
If it is determined in step S2 that the value is equal to or greater than the minimum management value d1 (that is, the life of the polishing pad 311c has not been exhausted), the process proceeds to step S11 described later. On the other hand, if it is determined in step S2 that it is thinner 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 to the upper side of the pad exchanging device 318, and uses this device 318 to exchange the polishing pad 311c with a new polishing pad. Thereafter, the control unit causes the pad thickness measuring device 319 to measure the thickness of the polishing pad 311c, similarly to 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 to make relative movements. The polishing pad 311c is rotated and subjected to break-in conditioning (step S6). Break-in conditioning is normally performed on a new polishing pad. For example, the conditioning time is set to a fixed time longer than that in normal conditioning (conditioning performed in steps S12 and S14), and the conditioner 317b. 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). After that, 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, whereby the polishing pad 311c in step S6 is obtained. An average cutting rate is calculated (step S8).
[0091]
Thereafter, the control unit determines whether or not the life of the conditioner 317b is exhausted by determining whether or not the average cutting rate calculated in step S8 is equal to or greater than the minimum management value R1 that determines the life of the conditioner 317b. Determine (step S9).
[0092]
If it is determined in step S9 that the value is equal to or greater than the minimum management value R1 (that is, the life of the conditioner 317b is not exhausted), each 1 of the polishing pad 311c performed in the next series of polishing (steps S12 and S14 described later). A conditioning time (one time) at which the amount of cutting of the polishing pad 311c by a single conditioning is a predetermined value is obtained from the average cutting rate calculated in step S8, and this conditioning time is conditioned during the next series of polishings. The conditioning time is reset in the internal memory of the control unit (step S10). Then, it returns to step S1.
[0093]
In step S11, the control unit predicts the thickness of the polishing pad 311c after polishing the number of wafers (N sheets) specified in step S1. In 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 of two wafers. Therefore, it is possible to calculate how many times the conditioning has 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 latest average cutting rate (obtained at steps S8, S18, S28). The predicted value of the thickness of the polishing pad 311c after polishing the N wafers in step S1 can be obtained by multiplying by the latest one of the average cutting rates.
[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 will not be exhausted 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 thinner than the minimum management value d1, the life of the polishing pad 311c will expire if N wafers are polished, and the process proceeds to step S13. . In step S13, the control unit obtains the maximum value M of the number of the polishing pads 311c that is predicted to be polished when a certain number of wafers have been polished, so that the thickness is not thinner than the minimum management value d1. As for the maximum value M, the predicted value of the polishing pad 311c is calculated for each number of sheets and compared with the minimum management value d1 as in the case of N wafers in step S11 under the condition of M <N. And you can ask for it. Then, the control unit resets the number of wafers to be polished in the actual series polishing from the N sheets designated in step S1 to M sheets (step S13), and proceeds to step S14.
[0096]
In step S <b> 12, the control unit causes each unit to perform the operation described in the above-described wafer flow, thereby polishing N wafers in series (that is, automatically and continuously polishing N wafers). When this series of polishing is completed, the process proceeds to step S15. In this example, when this series of polishing is completed, N unprocessed wafers Wd set in the cassette C1 are respectively stored as N processed wafers Wp in the cassette C4.
[0097]
In step S14, the control unit polishes the M wafers in series by causing each unit to perform the operation described in the flow of the wafers according to the setting of M sheets in step S13 (that is, the M wafers are processed). When this series of polishing is completed, the process proceeds to step S15. In this example, when this series of polishing is completed, M unprocessed wafers Wd set in the cassette C1 are respectively stored as M processed wafers Wp in the cassette C4.
[0098]
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, etc. Of course, one may be used). Each time three or more wafers are polished, 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 polishes the polishing head 311a. The head 311a and the conditioner holding member 317c are rotated and relatively rotated to condition the polishing pad 311c. The conditioning in steps S12 and S14 is performed according to the currently set conditioning time (conditioning time set latest 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, as in 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 defines 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 less than the minimum management value d1, the process proceeds to step S4. If it is equal to or greater than the minimum management value d1, the process proceeds to step S17.
[0100]
In step S17, the control unit calculates the difference between the pad thickness measured in step S15 and the pad thickness measured in step S3 from step 12 or step S14 (which step has been reached to reach step S17). The average cutting rate of the polishing pad 311c in the series of polishing is calculated by dividing by the conditioning accumulated time of the conditioning performed in (1).
[0101]
Next, the control unit determines whether or not the life of the conditioner 317b is exhausted by determining whether or not the average cutting rate calculated in step S17 is equal to or greater than the 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 greater than the minimum management value R1 (that is, the life of the conditioner 317b has not been exhausted), each one of the polishing pads 311c performed in the next series of polishing (steps S12 and S14) A conditioning time such that the amount of cutting of the polishing pad 311c by conditioning becomes a predetermined value is obtained from the average cutting rate calculated in step S8, and this conditioning time (one time) is obtained at the time of conditioning during the next series of polishings. The conditioning time is reset in the internal memory of the control unit (step S19). Then, it returns to step S1.
[0103]
When it is determined in steps S9 and S18 that the value is equal to or less than the minimum management value R1 (that is, the conditioner 317b has reached the end of its life), the control unit notifies the alarm unit 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, similar to step S2. (Step S22). Note that the control unit may know the replacement of the conditioner 317b by a signal from an exchange detection sensor (not shown) of the conditioner 317b. You may make it know by predetermined operation etc.
[0104]
Next, as in step S3, the control unit determines whether or not the pad thickness measured in step S22 is equal to or greater than a predetermined minimum management value d1 that defines the life of the polishing pad 311c. Then, it is determined whether or not the life of the polishing pad 311c has expired (step S23). If it is less than the minimum management value d1, the process proceeds to step S24, and if it is not less than the minimum management value d1, the process proceeds to step S26.
[0105]
In step S24, the control unit causes the pad exchange device 318 to replace the polishing pad 311c with a new polishing pad, as in step S4. Next, the control unit measures the thickness of the polishing pad 311c (step S25), and then proceeds to step S26.
[0106]
In step S26, the control unit causes the conditioning device 317 to break-in the polishing pad 311c 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 the process is completely the same when the process proceeds from YES to step S26 in step S23. This is not an essential break-in conditioning (initial conditioning of the polishing pad 311c), but a preliminary operation for determining the quality of the new conditioner 317b.
[0107]
Next, the control unit measures the thickness of the polishing pad 311c (step S27). Next, the control unit determines the difference between the pad thickness measured in step S25 or step S22 (this depends on whether or not it has reached step S25 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, thereby calculating the average cutting rate of the polishing pad 311c in step S26 (step S28).
[0108]
Thereafter, the control unit determines whether or not the conditioner 317b is acceptable by determining whether or not the average cutting rate in step S28 is within the range of the minimum management value R1 or more and the predetermined maximum management value R2 or less. Determination is made (step S29). If it is not within the range (if 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 the amount of cutting of the polishing pad 311c by the conditioning of the polishing pad 311c performed once 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 step (3), and the conditioning time (one time) is reset in the internal memory of the control unit as the conditioning time at the time of the next series of polishing. Then, it 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 that for the first polishing stage 310 is also performed for each of the polishing stages 320 and 330. The operation is performed in conjunction with judgment and processing. For example, after the determination in step S3 is made individually for the thickness of the polishing pad of each polishing head, the thickness of the polishing pad for all polishing heads is the minimum management value (may differ for each polishing head). Only in the above case, the process proceeds to step S11, and in other cases, the series of polishing is not performed. The number of wafers that are actually polished in series is determined according to the determination results of steps S11 and S13 regarding the polishing head of each polishing stage.
[0111]
According to the present embodiment, the thickness of the polishing pad 311c is measured in steps S2, S15, and S22. If the measured thickness is smaller than the predetermined value d1 in steps S3, S16, and S23, the polishing pad 311c is measured. 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 appropriately replaced. Therefore, it is possible to polish the wafer 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 quite early, and the replacement cost of the polishing pad can be reduced. To reduce.
[0112]
Further, according to the present embodiment, when the average cutting rate of the polishing pad 311c is calculated in steps S17 and S8, and the average cutting rate is lower than the predetermined value R1 in steps S18 and S9, the life of the conditioner 317b is increased. It is determined that the condition is exhausted, and the conditioner 317b is replaced with a new conditioner. Therefore, according to this Embodiment, the lifetime of a conditioner can be determined correctly and a conditioner can be replaced | exchanged appropriately. Therefore, it is possible to polish the wafer accurately by properly conditioning the polishing pad, and it is possible to prevent a situation where it is determined that the conditioner has reached the end of its life quite early and the conditioner replacement frequency is 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 the pad thickness is measured in steps S22 and S27 before and after that. Based on the result, the average cutting rate of the polishing pad is calculated in step S28. If the average cutting rate is outside 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 a conditioner having an appropriate cutting ability, so that the polishing pad can exhibit desired polishing characteristics, and consequently The wafer can be polished with high accuracy.
[0114]
Furthermore, according to the present embodiment, the average cutting rate of the polishing pad calculated in steps S18, S9, and S29 is adjusted to the conditioning conditions (conditions for this embodiment) during the next series of polishing operations in steps S19, S9, and S29. In this form, it is the conditioning time, but it is not necessarily limited to this.), So even if the conditioning surface of the conditioner is gradually worn out, its influence is greatly reduced, The condition of the polishing surface of the polishing pad after conditioning is almost constant with respect to each wafer. As a result, a large number of wafers can be polished stably and accurately.
[0115]
Moreover, according to this Embodiment, step S11, S13 is performed and the situation where the lifetime of a polishing pad runs out in the middle in a series of grinding | polishing is prevented. Therefore, also from this point, a large number of wafers can be polished stably and accurately.
[0116]
In the above-described embodiment, the pad exchange devices 318, 328, and 338 are provided. However, in the present invention, these are not necessarily required. If there is no pad changer 318, 328, 338, for example, an alarm may be issued to the operator that the polishing pad should be changed in step S4. Moreover, in the said embodiment, although the conditioner was changed manually, you may provide the conditioner exchange apparatus which replaces | exchanges a conditioner automatically. In this case, instead of generating an alarm in step S20, the conditioner may be replaced by the conditioner replacement device.
[0117]
In the present invention, in addition to precise polishing control in the Cu-CMP process, for example, in addition to wafer processing such as an interlayer insulating film processing process or STI process, a quartz substrate, a glass substrate, a ceramic substrate, etc. The same processing can be applied to the machining process.
[0118]
Furthermore, the polishing apparatus 1 according to the present embodiment is an example of a polishing apparatus that uses a four-divided index table 340 and performs polishing with three stages of polishing stages 310, 320, and 330. However, the present invention is not limited to this, and for example, a configuration in which polishing is performed with a two-stage polishing stage, or a configuration in which four or more stages of polishing stages are provided.
[0119]
[Second Embodiment]
[0120]
Next, an embodiment of a semiconductor device manufacturing method according to the present invention will be described. FIG. 6 is a flowchart showing a semiconductor device manufacturing process. The semiconductor device manufacturing process is started, and 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 one of steps S201 to S204.
[0121]
Step S201 is an oxidation process for 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 process for forming an electrode film on the silicon wafer by a process such as vapor deposition. Step S204 is an ion implantation process for implanting ions into the silicon wafer.
[0122]
After the CVD process (S202) or the electrode formation process (S203), the process proceeds to step S209 to determine whether or not to perform the CMP process. If not, the process proceeds to step S206; otherwise, the process proceeds to step S205. Step S205 is a CMP process. In this process, the polishing apparatus according to the present invention is used to planarize the interlayer insulating film, form a damascene by polishing the metal film on the surface of the semiconductor device, and the like. .
[0123]
After the CMP process (S205) or the oxidation process (S201), the process proceeds to step S206. Step S206 is a photolithography process. 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 apparatus, and the exposed silicon wafer is developed. Further, the next step S207 is an etching process in which portions other than the developed resist image are etched away, and then the resist is peeled off to remove the unnecessary resist after etching.
[0124]
Next, in step S208, it is determined whether all necessary processes are completed. If not completed, 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 processes 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 process, the processing accuracy of the CMP process is improved without using a polishing pad or a conditioner that has reached the end of its life, Running cost can be reduced. Thereby, it is possible to manufacture a semiconductor device with less manufacturing variation compared to the conventional semiconductor device manufacturing method at a low cost. In addition, the semiconductor device manufactured by the semiconductor device manufacturing method according to the present invention is a semiconductor device that has a high yield and is inexpensive. Note that the polishing apparatus according to the present invention may be used in a CMP process of a semiconductor device manufacturing process other than the semiconductor device manufacturing process.
[0126]
As mentioned above, although each embodiment of this invention and its modification were demonstrated, this 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 that can accurately determine the life of a polishing pad or a conditioner.
[0128]
Furthermore, according to this invention, the quality determination method of the conditioner which can determine the quality of a new conditioner appropriately can be provided.
[0129]
Furthermore, according to the present invention, it is possible to provide a polishing pad conditioning method capable of polishing each object to be polished in the same manner.
[0130]
Moreover, according to this invention, the grinding | polishing apparatus which can reduce a running cost can be provided.
[0131]
Furthermore, this invention can provide the grinding | polishing apparatus which can grind | polish similarly about each to-be-polished object.
[0132]
Furthermore, the present invention can provide a semiconductor device manufacturing method capable of manufacturing a semiconductor device at a low cost and a low cost semiconductor device as compared with a conventional semiconductor device manufacturing method.
[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.
2 is a schematic top view showing how a wafer is processed by the polishing apparatus shown in FIG. 1; 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.
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 equipment
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 changing device
319,329,339 Pad thickness measuring device
340 Index table
350 Transfer stage

Claims (7)

A life determination 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 using the conditioner for a cumulative conditioning time;
Measure the thickness of the polishing pad before and after conditioning for the cumulative conditioning time,
Based on the thickness of the polishing pad measured before and after conditioning of the cumulative conditioning time, an average cutting rate during the cumulative conditioning time of the polishing pad is determined,
When the average cutting rate is lower than a predetermined value, it is determined that the conditioner has reached the end of its life. A conditioner comprising a life determination stage for determining the life of a conditioner used for conditioning a polishing pad used for polishing an object to be polished, and a pass / fail determination stage for determining pass / fail of a new conditioner used for conditioning The determination method of
The life determination step is performed by a conditioner life determination method according to claim 1,
The pass / fail determination step includes a step of conditioning the polishing pad using the new conditioner, a step of measuring the thickness of the polishing pad before and after conditioning of the cumulative conditioning time, and the cumulative conditioning. based on the thickness of the polishing pad that is measured before and after the time of conditioning, the the steps asking you to average cutting rate in the cumulative conditioning time of the polishing pad, when the average cutting rate is out of the predetermined range, and a step of the new conditioner is determined to be defective,
Conditioners determine the constant wherein the. Step of determining said is defective, wherein, when the average cutting rate is greater than the predetermined range, determine a constant process according conditioner to claim 2, characterized in that the new conditioner is determined to be defective . In a polishing apparatus for polishing the object to be polished by relatively moving the polishing pad and the object to be polished 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;
A measurement unit for measuring the thickness of the polishing pad at a first timing and a second timing thereafter;
The polishing pad by the conditioner within 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 calculation unit for calculating an average cutting rate during the cumulative conditioning time of
A means for generating an alarm that the conditioner should be replaced with a new conditioner when the average cutting rate is lower than a predetermined value, or for automatically replacing the conditioner with a new conditioner;
A polishing apparatus comprising: The measurement unit includes a third timing before a new conditioner is mounted on the conditioning unit and the new conditioner is used for conditioning the polishing pad, and then the polishing pad using the new conditioner. At the fourth timing after conditioning, the thickness of the polishing pad is measured ,
The arithmetic unit, the third on the basis of the thickness measured by said fourth timing and the thickness measured by the timing, in the period from the third time to the fourth time, the new Calculate the average cutting rate during the cumulative conditioning time of the polishing pad by the conditioner ,
Said means, when the average cutting rate in the period from the third time to the fourth time is out of the predetermined range, an alarm to the effect that exchange in the newer conditioner new conditioner automatically replacing the further new conditioner or generates or the new conditioner,
The polishing apparatus according to claim 4 . Said means, when the average cutting rate is greater than the predetermined range in the period from the third time to the fourth time, a warning to the effect that exchange the new conditioner newer conditioner the polishing apparatus according to claim 5, wherein the exchanging the generated or automatically newer conditioner the new conditioner. Using the polishing apparatus according to any one of claims 4 to 6, the semiconductor device manufacturing method characterized by comprising the step of flattening the surface of the semiconductor wafer.

Images