JP2021130157A - Processing method and processing device - Google Patents

Abstract

To shorten warm-up time of a substrate processing device.SOLUTION: A processing method for a substrate W includes: repeating rotation and stopping of a holding part 42 holding the substrate W and performing warm-up to raise a temperature of the holding part 42 to a desired temperature; and grinding the substrate W held by the holding part 42 while rotating the holding part 42 after the warm-up. A processing device for a substrate W includes a holding part 42 for holding the substrate W, a holding driving part 44 for rotating the holding part 42, and a control unit for controlling a processing process on the substrate W.SELECTED DRAWING: Figure 4

Description

The present disclosure relates to a processing method and a processing apparatus.

Patent Document 1 describes a holding means for holding a wafer, a processing water supply means for supplying processing water (grinding water) to the wafer held by the holding means, and grinding for grinding the wafer held by the holding means. Grinding devices with means are disclosed. In the grinding device, in order to maintain the same environment as during grinding (for example, the temperature of the holding means and the grinding means) during idling without grinding such as before grinding and when replacing the wafer, the grinding water flows out. I'm leaving it.

Japanese Unexamined Patent Publication No. 2003-326458

The technique according to the present disclosure shortens the warm-up time of the substrate processing apparatus.

One aspect of the present disclosure is a method of processing a substrate, in which the holding portion holding the substrate is repeatedly rotated and stopped to warm up the temperature of the holding portion to a desired temperature, and the warm-up is performed. After that, the substrate held by the holding portion is ground while rotating the holding portion.

According to the present disclosure, the warm-up time of the substrate processing apparatus can be shortened.

It is a graph which shows the shape change of the wafer after the processing process when the temperature of the processing apparatus is not stable. It is a graph which shows the shape change of the wafer after the processing process when the temperature of the processing apparatus is stable. It is a top view which shows the outline of the structure of the processing apparatus. It is a side view which shows an example of the structure of each grinding unit and a chuck.

In recent years, in a semiconductor device manufacturing process, a semiconductor wafer (hereinafter referred to as "wafer") in which devices such as a plurality of electronic circuits are formed on the front surface is ground on the back surface of the wafer to thin the wafer. Is being done.

Grinding of the back surface of the wafer is performed using, for example, the grinding apparatus disclosed in Patent Document 1. That is, while rotating the holding means while holding the front surface of the wafer by the holding means, the grinding wheel of the grinding means is brought into contact with the back surface of the wafer to grind the back surface of the wafer.

Here, as a result of diligent studies by the present inventors, when the warm-up (idling) of the processing apparatus (grinding apparatus) is not sufficient and the temperature of the apparatus is not stable, the shape of the wafer changes as the wafer is processed. I found out to do.

FIG. 1 shows a change in the shape of the wafer when the warm-up time of the processing device is not sufficient and the temperature of the device is not stable, and FIG. 2 shows a change in the shape of the wafer when the warm-up time of the processing device is sufficient and the temperature of the device is high. It shows the shape change of the wafer when it is stable. In FIGS. 1 and 2, the horizontal axis represents the number of wafers to be processed, the first vertical axis represents the TTV (Total Tickness Variation) of the wafers, and the second vertical axis represents the desired temperature of 0. When (zero) is set, the temperature with respect to the desired temperature (stable temperature) is shown. As for this temperature, a thermometer (thermocouple) was provided around the chuck holding the wafer to measure the temperature. Specifically, the temperature of the lower part (inside the device) on the lower surface side of the chuck was measured.

As shown in FIG. 1, when the warm-up time is short and the temperature of the apparatus is not sufficiently adjusted by the warm-up, that is, when the temperature of the apparatus rises during the processing of the wafer, the shape of the wafer changes as it is processed. .. In other words, if the temperature of the device is not stable, the wafer W cannot have the desired shape and TTV.

On the other hand, as shown in FIG. 2, when the warm-up time is sufficiently long and the temperature of the apparatus is sufficiently adjusted by the warm-up, that is, when the temperature of the apparatus is stable during the processing of the wafer, the wafer processing process is performed. The shape of the wafer does not change even if the wafers are stacked. In other words, if the temperature of the device is stable, the wafer W can have the desired shape and TTV.

However, if it takes a long time to warm up, the downtime of the apparatus becomes long, and the throughput of the wafer processing process decreases. Therefore, it is desired to shorten the warm-up time. For example, in the conventional warm-up disclosed in Patent Document 1, although it is considered to maintain the same environment as during grinding, the warm-up time is desired. No measures have been taken to reduce time. Therefore, there is room for improvement in warming up conventional processing equipment.

The technique according to the present disclosure shortens the warm-up time of the substrate processing apparatus. Hereinafter, the processing apparatus and processing method according to the present embodiment will be described with reference to the drawings. In the present specification and the drawings, elements having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.

As shown in FIG. 3, in the processing apparatus 1 of the present embodiment, the wafer W as a substrate is thinned. The wafer W is a semiconductor wafer such as a silicon wafer or a compound semiconductor wafer. A device is formed on the surface of the wafer W (hereinafter, referred to as “surface Wa”). Then, a process such as grinding is performed on the back surface of the wafer W (hereinafter, referred to as “back surface Wb”) to thin the wafer.

The processing device 1 has a configuration in which the loading / unloading station 2 and the processing station 3 are integrally connected. At the loading / unloading station 2, for example, a cassette C capable of accommodating a plurality of wafers W is loaded / unloaded from the outside. The processing station 3 includes various processing devices that perform desired processing on the wafer W.

The loading / unloading station 2 is provided with a cassette mounting table 10. In the illustrated example, a plurality of, for example, four cassettes C can be freely mounted in a row on the cassette mounting table 10 in the X-axis direction. The number of cassettes C mounted on the cassette mounting table 10 is not limited to this embodiment and can be arbitrarily determined.

The loading / unloading station 2 is provided with a wafer transfer region 20 adjacent to the cassette mounting table 10 on the Y-axis positive direction side of the cassette mounting table 10. The wafer transfer region 20 is provided with a wafer transfer device 22 configured to be movable on a transfer path 21 extending in the X-axis direction.

The wafer transfer device 22 has a transfer fork 23 that holds and conveys the wafer W before and after the grinding process. The tip of the transport fork 23 is branched into two, and the wafer W is sucked and held. Further, the transport fork 23 is configured to be movable in the horizontal direction, the vertical direction, the horizontal axis, and the vertical axis. The configuration of the wafer transfer device 22 is not limited to this embodiment, and any configuration can be adopted. The wafer transfer device 22 is configured to transfer the wafer W to the cassette C of the cassette mounting table 10, the alignment unit 50, and the first cleaning unit 60.

At the processing station 3, processing processing such as grinding and cleaning is performed on the wafer W. The processing station 3 includes a transfer unit 30 for transporting the wafer W, a grinding unit 40 for grinding the wafer W, an alignment unit 50 for adjusting the horizontal orientation of the wafer W before the grinding process, and the wafer W after the grinding process. It has a first cleaning unit 60 for spin-cleaning the back surface Wb of the wafer W, and a second cleaning unit 70 for cleaning the front surface Wa of the wafer W after grinding.

The transport unit 30 is an articulated robot provided with a plurality of, for example, three arms 31. Each of the three arms 31 is configured to be rotatable. A transport pad 32 that attracts and holds the wafer W is attached to the arm 31 at the tip. Further, the base end arm 31 is attached to an elevating mechanism 33 that elevates and elevates the arm 31 in the vertical direction. The configuration of the transport unit 30 is not limited to this embodiment, and any configuration can be adopted. The transfer unit 30 is configured to be able to transfer the wafer W to the delivery position A0, the alignment unit 50, the first cleaning unit 60, and the second cleaning unit 70 of the grinding unit 40, which will be described later.

The grinding unit 40 is provided with a rotary table 41. On the rotary table 41, four chucks 42 are provided as holding portions for sucking and holding the wafer W. The four chucks 42 can be moved to the delivery position A0 and the processing positions A1 to A3 by rotating the rotary table 41.

At the delivery position A0, the wafer W is delivered by the transfer unit 30. A rough grinding unit 80 is arranged at the processing position A1 to roughly grind the wafer W. A medium grinding unit 90 is arranged at the processing position A2 to perform medium grinding of the wafer W. A finish grinding unit 100 is arranged at the processing position A3 to finish grind the wafer W.

For example, a porous chuck is used as the chuck 42 to adsorb and hold the surface Wa of the wafer W. The surface of the chuck 42, that is, the holding surface of the wafer W, has a convex shape in which the central portion protrudes from the end portion in a side view. Since the protrusion at the center is very small, the convex shape of the chuck 42 is omitted in the drawing.

As shown in FIG. 4, the chuck 42 is held by the chuck base 43. The chuck base 43 is provided with a rotation mechanism 44 for rotating the chuck 42 and the chuck base 43, and an inclination adjusting mechanism 45 for adjusting the inclination of the chuck 42 and the chuck base 43 from the horizontal direction.

The rotation mechanism 44 includes a rotation shaft 110 for rotating the chuck 42, a drive unit 120 for imparting a rotation drive when rotating the chuck 42, and a drive transmission unit 130 for transmitting the rotation drive by the drive unit 120 to the rotation shaft 110. have. The rotating shaft 110 is fixedly provided at the center of the lower surface of the chuck base 43. Further, the rotating shaft 110 is rotatably supported by the support base 111. The chuck 42 rotates around the rotation shaft 110.

The drive unit 120 is provided independently of the rotating shaft 110. The drive unit 120 has a drive shaft 121 and a motor 122 that rotates the drive shaft 121. The drive unit 120 corresponds to the holding drive unit in the present disclosure.

The drive transmission unit 130 has a driven pulley 131 provided on the rotating shaft 110, a drive pulley 132 provided on the drive shaft 121, and a belt 133 wound around the driven pulley 131 and the drive pulley 132. .. The rotary drive by the drive unit 120 is transmitted to the rotary shaft 110 via the drive pulley 132, the belt 133, and the driven pulley 131.

The configuration of the rotation mechanism 44 is not limited to this, and can be arbitrarily selected as long as the chuck 42 can be rotated.

The tilt adjusting mechanism 45 has one fixed shaft 140 provided on the lower surface of the chuck base 43, and a plurality of, for example, two elevating shafts 141 and 141. Each elevating shaft 141 is flexibly configured by a motor 142 to elevate and elevate the chuck base 43. The tilt adjusting mechanism 45 raises and lowers the other end of the chuck base 43 in the vertical direction with the elevating shaft 141 from one end (position corresponding to the fixed shaft 140) of the outer peripheral portion of the chuck base 43, whereby the chuck 42 and the chuck base are raised and lowered. 43 can be tilted. As a result, the relative inclination of the various grinding units at the processing positions A1 to A3 and the chuck 42, that is, the inclination of the back surface Wb of the wafer W with respect to the grinding wheel provided by the various grinding units can be adjusted.

The configuration of the inclination adjusting mechanism 45 is not limited to this, and can be arbitrarily selected as long as the relative angle (parallelism) of the wafer W with respect to the grinding wheel can be adjusted.

The rough grinding unit 80 includes a rough grinding wheel 81 having a rough grinding wheel on an annular lower surface, a mount 82 for supporting the rough grinding wheel 81, a spindle 83 for rotating the rough grinding wheel 81 via the mount 82, and, for example. It has a drive unit 84 containing a motor (not shown). Further, the rough grinding unit 80 is configured to be movable in the vertical direction and the horizontal direction along the support column 85 shown in FIG. Then, in the rough grinding unit 80, the wafer W held by the chuck 42 and a part of the arc of the annular rough grinding wheel are brought into contact with each other, and the chuck 42 and the rough grinding wheel 81 are rotated to obtain the wafer. Roughly grind the back surface Wb of W.

As shown in FIGS. 3 and 4, the medium grinding unit 90 has the same configuration as the rough grinding unit 80. That is, the medium grinding unit 90 has a medium grinding wheel 91 including an annular medium grinding wheel, a mount 92, a spindle 93, a drive unit 94, and a support column 95. The particle size of the abrasive grains of the medium grinding wheel is smaller than the particle size of the abrasive grains of the coarse grinding wheel.

As shown in FIGS. 3 and 4, the finish grinding unit 100 has the same configuration as the rough grinding unit 80 and the medium grinding unit 90. That is, the finish grinding unit 100 has a finish grinding wheel 101 including an annular finish grinding wheel, a mount 102, a spindle 103, a drive unit 104, and a support column 105. The particle size of the abrasive grains of the finishing grinding wheel is smaller than the particle size of the abrasive grains of the medium grinding wheel.

In the present embodiment, the grinding wheels 81, 91, 101, the mounts 82, 92, 102, and the spindles 83, 93, 103 constitute the grinding portion in the present disclosure. Further, the drive units 84, 94, and 104 correspond to the grinding drive units in the present disclosure.

As shown in FIG. 3, the above processing apparatus 1 is provided with a control unit 150. The control unit 150 is, for example, a computer equipped with a CPU, a memory, or the like, and has a program storage unit (not shown). The program storage unit stores a program that controls the processing of the wafer W in the processing apparatus 1. The program may be recorded on a computer-readable storage medium H and may be installed on the control unit 150 from the storage medium H.

Next, a processing method performed using the processing apparatus 1 configured as described above will be described.

First, the cassette C containing a plurality of wafers W is placed on the cassette mounting table 10 of the loading / unloading station 2. Next, the wafer W is taken out from the cassette C by the transfer fork 23 of the wafer transfer device 22, and is transferred to the alignment unit 50 of the processing station 3. In the alignment unit 50, the horizontal orientation of the wafer W is adjusted by adjusting the position of the notch portion (not shown) formed in the wafer W.

The wafer W whose horizontal orientation is adjusted is then conveyed from the alignment unit 50 by the transfer unit 30 and delivered to the chuck 42 at the delivery position A0. Subsequently, the rotary table 41 is rotated to sequentially move the chuck 42 to the machining positions A1 to A3.

At the processing position A1, the rough grinding unit 80 roughly grinds the back surface Wb of the wafer W. At the processing position A2, the back surface Wb of the wafer W is medium-ground by the medium-grinding unit 90. Further, at the processing position A3, the finish grinding unit 100 finish grinds the back surface Wb of the wafer W.

Next, the rotary table 41 is rotated to move the chuck 42 to the delivery position A0. Subsequently, the wafer W is conveyed from the delivery position A0 to the second cleaning unit 70 by the transfer unit 30, and the surface Wa of the wafer W is cleaned and dried while being held by the transfer pad 32.

Next, the wafer W is transported from the second cleaning unit 70 to the first cleaning unit 60 by the transport unit 30, and the back surface Wb of the wafer W is cleaned using a cleaning liquid nozzle (not shown).

After that, the wafer W that has been subjected to all the processing is transferred to the cassette C of the cassette mounting table 10 by the transfer fork 23 of the wafer transfer device 22. In this way, a series of processing processes in the processing apparatus 1 are completed.

Next, a method of warming up the processing apparatus 1 will be described. Warm-up is performed before restarting wafer processing, for example, after the power of the device is turned on, or when the wafer W is not processed for a long time (when there is a factor that the temperature inside the device deviates from the optimum temperature at the time of processing). This is a process of raising the temperature of the processing apparatus 1 to a desired temperature.

In the following description, a case where the chuck 42 in the processing apparatus 1 is warmed up will be described. That is, in the present embodiment, the temperature of the chuck 42 is raised to a desired temperature during warm-up.

Here, as shown in FIG. 1, when the chuck 42 is not sufficiently warmed up and the temperature of the chuck 42 is not stable, the shape of the wafer W changes as the wafer W is processed. On the other hand, when the chuck 42 is sufficiently warmed up and the temperature of the chuck 42 is stable, the shape of the wafer does not change even if the processing of the wafer W is repeated. Therefore, in order to obtain the desired shape and TTV of the wafer W after the processing, it is necessary to raise the chuck 42 to a desired temperature, that is, a temperature required for the processing, by warming up.

However, if it takes a long time to warm up, the downtime of the apparatus becomes long, and the throughput of the processing of the wafer W decreases. Therefore, it is desired to shorten the warm-up time. Therefore, as a result of diligent studies by the present inventors, it has been found that the temperature of the chuck 42 can be raised in a short time to a desired temperature by repeatedly rotating and stopping the chuck 42 in the warm-up. In the following description, the state in which the chuck 42 is rotated is referred to as "rotation on", and the state in which the rotation of the rotating chuck 42 is stopped (the state in which the rotation speed is zero) is referred to as "rotation off".

The present inventors have compared the temperature change of the chuck 42 when the rotation of the chuck 42 is repeatedly turned on and off with the temperature change of the chuck 42 when the chuck 42 is continuously rotated.

Then, a thermometer (thermocouple) was provided around the chuck 42 to measure the temperature. When the rotation of the chuck 42 was turned on and off, the rotation speed was repeatedly performed between 0 rpm and 293 rpm. That is, the chuck 42 is accelerated and rotated from 0 rpm to 293 rpm in the state where the rotation is on, and the chuck 42 is decelerated and rotated from 293 rpm to 0 rpm in the state where the rotation is off. When the chuck 42 was continuously rotated, the rotation speed was kept constant at 293 rpm.

When the rotation of the chuck 42 was repeatedly turned on and off, the temperature rise rate was higher than that when the chuck 42 was continuously rotated. As an example, when the chuck 42 was continuously rotated, it took 100 minutes to reach the desired temperature, whereas when the rotation of the chuck 42 was repeatedly turned on and off, it took 60 minutes. Therefore, by repeating the rotation on / off of the chuck 42, the temperature of the chuck 42 can be raised to a desired temperature more quickly, the temperature can be stabilized, and the warm-up time can be shortened.

More specifically, the motor 122 of the rotation mechanism 44 that rotates the chuck 42 is likely to be loaded and generate heat during acceleration and deceleration. In particular, at the initial stage of rotation in which the chuck 42 is accelerated and rotated from the stopped state (the state where the rotation speed is zero), and at the end of the rotation where the chuck 42 is decelerated and rotated from the rotated state and stopped (the rotation speed is set to zero), the motor 122 emits a large amount of heat. Then, by repeating the rotation on / off of the chuck 42, a large amount of energy is repeatedly applied from the motor 122 to the chuck 42, so that the temperature of the chuck 42 tends to rise.

According to the above embodiment, when the chuck 42 is warmed up, the rotation of the chuck 42 is repeatedly turned on and off, so that the temperature rise rate of the chuck 42 can be increased and the time to reach the desired temperature is shortened. be able to. Then, since the processing (grinding process) is performed on the wafer W in a state where the chuck 42 is surely stabilized at a desired temperature, the wafer W after the processing process can have a desired shape and TTV.

When the chuck 42 rises to a desired temperature, for example, the maximum temperature reached in the apparatus during warm-up, the wafer W can be processed at any time. If there is time to process the wafer W after the chuck 42 has risen to a desired temperature, for example, the rotation speed of the chuck 42 may be kept constant so as to maintain the temperature of the chuck 42.

The interval at which the chuck 42 is rotated on / off is not particularly limited, but it is preferable to shorten the interval as much as possible and repeat the rotation on / off many times. By repeating the rotation on / off as many times as possible within the range where the motor 122 does not step out, the temperature of the chuck 42 can be raised in a shorter time. Moreover, the controllability of the temperature of the chuck 42 is also improved.

Further, the maximum rotation speed of the chuck 42 at the time of warming up is not particularly limited. For example, the rotation speed of the chuck 42 is repeatedly turned on and off between 0 rpm and 300 rpm.

In the above embodiment, the chuck 42 is repeatedly rotated on and off during warm-up to raise the chuck 42 to a desired temperature, but the temperature adjustment target is not limited to the chuck 42. For example, the spindles 83, 93, 103 may be repeatedly turned on and off to raise the spindles 83, 93, 103 to a desired temperature.

As a result of diligent studies by the present inventors, it was found that the spindles 83, 93, and 103 have the same tendency as the temperature change of the chuck 42. That is, when the spindles 83, 93, 103 or the grinding wheels 81, 91, 101 are repeatedly rotated on and off, the temperature rise rate is higher than when the spindles 83, 93, 103 or the grinding wheels 81, 91, 101 are continuously rotated. Therefore, the warm-up time can be shortened.

The interval at which the spindles 83, 93, and 103 are rotated on / off is not particularly limited, but it is preferable to shorten the interval as much as possible and repeat the rotation on / off many times.

Further, the maximum rotation speeds of the spindles 83, 93, and 103 during warm-up are not particularly limited. For example, the rotation speed of the spindles 83, 93, and 103 may be repeatedly turned on and off between 0 rpm and 4000 rpm.

In the above embodiment, the case where the wafer W is ground and thinned in the processing apparatus 1 has been described as an example, but the present invention is not limited to this. For example, in a polymerized wafer in which a first wafer and a second wafer are joined, the present embodiment can be applied even when the first wafer is ground and thinned.

The embodiments disclosed this time should be considered to be exemplary in all respects and not restrictive. The above embodiments may be omitted, replaced or modified in various forms without departing from the scope of the appended claims and their gist.

1 Processing equipment 42 Chuck 120 Drive unit 150 Control unit W wafer

Claims (8)

It is a method of processing a substrate.
By repeating the rotation and stop of the holding part that holds the substrate, warming up is performed to raise the temperature of the holding part to a desired temperature, and
A processing method comprising, after the warm-up, grinding the substrate held by the holding portion while rotating the holding portion. The processing method according to claim 1, wherein when the warm-up is performed, the grinding portion that grinds the substrate held by the holding portion is repeatedly rotated and stopped to raise the temperature of the grinding portion to a desired temperature. The grinding unit includes a grinding wheel that abuts on a substrate to grind, and a spindle that rotates the grinding wheel.
The processing method according to claim 2, wherein at least the spindle is raised to a desired temperature when the warm-up is performed. The processing method according to claim 3, wherein when the warm-up is performed, the spindle is repeatedly rotated and stopped to raise the temperature of the spindle to a desired temperature. It is a substrate processing device
A holding part that holds the board and
A holding drive unit that rotates the holding unit and
It is equipped with a control unit that controls the processing of the substrate.
The control unit
By repeating the rotation and stop of the holding portion, warm-up is performed to raise the temperature of the holding portion to a desired temperature, and
A processing device that controls the operation of the holding portion and the holding driving portion so as to grind the substrate held by the holding portion while rotating the holding portion after the warm-up. A grinding part that grinds the substrate held by the holding part, and
A grinding drive unit for rotating the grinding unit is provided.
The control unit controls the operation of the grinding unit and the grinding drive unit so as to repeatedly rotate and stop the grinding unit to raise the temperature of the grinding unit to a desired temperature when the warm-up is performed. , The processing apparatus according to claim 5. The grinding unit includes a grinding wheel that abuts on a substrate to grind, and a spindle that rotates the grinding wheel.
The processing apparatus according to claim 6, wherein the control unit controls the operation of the grinding unit and the grinding drive unit so as to raise at least the spindle to a desired temperature when the warm-up is performed. The processing apparatus according to claim 7, wherein the control unit repeatedly rotates and stops the spindle to raise the temperature of the spindle to a desired temperature when the warm-up is performed.

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