KR20230029819A - Substrate processing system, substrate processing method and storage medium - Google Patents

Abstract

A substrate processing system for processing a substrate, comprising a grinding unit for grinding a processing surface of the substrate, a thickness measurement unit for measuring the thickness of the substrate, and a control unit for controlling an operation of the thickness measurement unit, the thickness measurement unit comprising: A contact measuring mechanism for measuring the thickness of the substrate in contact with the processing surface of the substrate, and a non-contact measuring mechanism for measuring the thickness of the substrate without contact with the substrate, wherein the control unit is configured to: In the substrate grinding treatment by the contact measuring mechanism, control of the thickness measurement operation of the substrate by the contact measuring mechanism and control of the measurable determination operation by the non-contact measuring mechanism are performed in parallel, and the measurable In the control of the determination operation, a difference value between one thickness measurement value obtained by the non-contact measurement mechanism and another thickness measurement value obtained immediately before the one thickness measurement value is successively calculated over time, When the calculated difference value continuously falls within a predetermined threshold value, it is determined that the thickness measurement of the substrate is possible, and control is performed to start the operation of measuring the thickness of the substrate by the non-contact measurement mechanism.

Description

Substrate processing system and substrate processing method

The present disclosure relates to a substrate processing system and a substrate processing method.

In Patent Document 1, as a method for measuring the thickness of a wafer, a pair of contactors of a two-point type process gauge are applied to each of the surface of the wafer and the surface of the chuck in a state where the wafer is vacuum-sucked with a chuck during or after grinding. On the other hand, it is disclosed to measure the difference in the measured height as the thickness of the wafer.

Further, in Patent Document 2, in a processing device, one surface of a substrate is held by a holding means, a laser beam is irradiated toward the other surface of the substrate in a direction substantially orthogonal to the other surface, and one of the laser beams is Disclosed is a method of receiving an interference wave of reflected light from a surface and reflected light from another surface, and deriving the thickness of a substrate based on the waveform of the interference wave.

Japanese Patent Laid-Open No. 2001-9716 Japanese Patent Laid-Open No. 2009-50944

In the technique according to the present disclosure, in measuring the thickness of a substrate during grinding, switching from thickness measurement using a contact thickness measurement mechanism to thickness measurement using a non-contact thickness measurement mechanism is appropriately performed.

One aspect of the present disclosure is a substrate processing system for processing a substrate, comprising: a grinding unit for grinding a processing surface of the substrate; a thickness measurement unit for measuring the thickness of the substrate; and a control unit for controlling the operation of the thickness measurement unit. The thickness measuring unit includes a contact measuring mechanism for measuring the thickness of the substrate in contact with the processing surface of the substrate, and a non-contact measuring mechanism for measuring the thickness of the substrate without contact with the substrate, wherein the In the grinding process of the substrate by the grinding unit, the control unit performs control of the thickness measurement operation of the substrate by the contact measuring mechanism and control of measurable determination operation by the non-contact measuring mechanism. In parallel, in the control of the measurable determination operation, the difference value between one thickness measurement value obtained by the non-contact measurement mechanism and another thickness measurement value obtained immediately before the one thickness measurement value is neglected. Control to determine that the thickness of the substrate can be measured when the calculated difference values continuously fall within a predetermined threshold value, and start the thickness measurement operation of the substrate by the non-contact measuring mechanism. do

According to the present disclosure, in measuring the thickness of a substrate during grinding, it is possible to appropriately switch from thickness measurement using a contact thickness measurement mechanism to thickness measurement using a non-contact thickness measurement mechanism.

1 is a side view schematically illustrating the configuration of a substrate to be processed.
Fig. 2 is a plan view schematically illustrating the configuration of a processing device.
3 is a side view showing an example of the configuration of each grinding unit and chuck.
Fig. 4 is a side view schematically illustrating the configuration of a contact-type measuring mechanism.
Fig. 5 is a side view schematically illustrating the configuration of a non-contact measurement mechanism.
Fig. 6 is an explanatory diagram showing a state of thickness measurement by a contact-type measuring mechanism.
7 : is explanatory drawing which shows the state of switching of a thickness measuring part.
8 : is explanatory drawing which shows the state of switching of a thickness measuring part.
Fig. 9 is an explanatory diagram showing a state of thickness measurement by a non-contact measuring mechanism.
10 is an explanatory diagram showing an example of another substrate processing method.

In recent years, in the manufacturing process of semiconductor devices, with respect to a semiconductor substrate (hereinafter simply referred to as a 'wafer') on which devices such as a plurality of electronic circuits are formed on the surface, grinding the back surface of the wafer to thin the wafer is performed. there is. The grinding of the back side of the wafer is performed, for example, by bringing the grinding wheel of the grinding unit into contact with the back side of the wafer while rotating the substrate holding unit in a state where the front surface of the wafer is held by the substrate holding unit.

This wafer grinding process is performed while measuring the thickness of the wafer in order to properly process the wafer as a product to a target thickness. In Patent Document 1 described above, the thickness of the wafer during grinding is measured by contacting one of the contacts of a two-way process gauge with the chuck surface and the other contact with the upper surface of the wafer (rear surface, which is the grinding surface), to measure the height of the wafer. A thickness measuring means of is disclosed.

However, in the case of using a contact-type thickness measuring device as disclosed in Patent Document 1, there is a possibility that the back surface of the wafer may be damaged by the contactor contacting the wafer. In addition, when using a contact-type thickness measurement means, the thickness of the wafer cannot be measured considering the thickness of a protective tape for protecting devices formed on the surface of the wafer, that is, the thickness of the wafer itself cannot be measured appropriately. . For this reason, conventionally, as disclosed in Patent Literature 2, it is proposed to use a non-contact type thickness measurement means capable of measuring the thickness of the wafer itself using an interference wave of a laser beam without bringing a contactor into contact with the wafer.

However, such a non-contact type thickness measurement means has limitations on the thickness of the wafer that can be measured (detection range: eg 5 to 300 μm), and when the wafer thickness deviate from this detection range, the contact type It is necessary to use the thickness measurement means of In the case of using both the contact and non-contact thickness measuring means in this way, the thickness measuring means is switched from the contact type to the non-contact type during the wafer grinding process. There was a risk that it could not be measured with Specifically, in a step where the thickness of the wafer cannot be accurately measured stably by a non-contact type thickness measuring means, for example, in a step where the back surface of the wafer, which is the incident surface of the laser beam, is rough, the thickness measuring means is changed from a contact type to a non-contact type. In the case of switching, there was a possibility that the thickness of the wafer could not be accurately measured.

The technology according to the present disclosure was made in view of the above circumstances, and in measuring the thickness of a substrate during grinding, switching from thickness measurement using a contact thickness measurement mechanism to thickness measurement using a non-contact thickness measurement mechanism Do it properly. Hereinafter, a processing device as a wafer processing system and a wafer processing method according to the present embodiment will be described with reference to the drawings. In this specification and drawings, elements having substantially the same functional configuration are given the same reference numerals to omit redundant description.

In the processing apparatus 1 according to the present embodiment, thinning of the wafer W as a substrate is performed. The wafer W is, for example, a semiconductor wafer such as a silicon wafer or a compound semiconductor wafer, and as shown in FIG. 1, a device D is formed on the surface Wa, and for protecting the device D A protective tape (T) is attached. Then, in the processing apparatus 1, processing such as grinding is performed on the back surface Wb of the wafer W, and thereby the wafer W is thinned.

As shown in FIG. 2 , the processing device 1 has a structure in which a carry-in/out station 2 and a processing station 3 are integrally connected. In the carry-in/out station 2, cassettes C capable of accommodating a plurality of wafers W are carried in/out with the outside, for example. The processing station 3 includes various processing devices that perform desired processing on the wafer W.

A cassette placing table 10 is provided in the carry-in/out station 2 . Further, on the side of the cassette placing table 10 in the positive Y-axis direction, a wafer transfer area 20 is provided adjacent to the cassette placing table 10 . In the wafer transport area 20 , a wafer transport device 22 configured to be movable on a transport path 21 extending in the X-axis direction is provided.

The wafer transport device 22 has a transport fork 23 that holds and transports the wafer W. The conveying fork 23 is configured to be movable in a horizontal direction, a vertical direction, around a horizontal axis, and around a vertical axis. The wafer transfer device 22 is configured to be able to transfer the wafer W to the cassette C of the cassette placing table 10, the alignment unit 50, and the first cleaning unit 60. .

In the processing station 3, processing processing such as grinding and cleaning is performed on the wafer W. The processing station 3 includes a conveyance unit 30 that transports the wafer W, a grinding unit 40 that grinds the wafer W, and adjusts the horizontal direction of the wafer W before the grinding process. an alignment unit 50 that cleans the back surface Wb of the wafer W after the grinding process; and a second cleaning unit 60 that cleans the front surface Wa of the wafer W after the grinding process. It has a government (70).

The transfer unit 30 is an articulated robot equipped with a plurality of arms 31, for example, three. As for the three arms 31, each is comprised so that turning is possible. A transfer pad 32 for sucking and holding the wafer W is attached to the distal end arm 31 . In addition, the base arm 31 is attached to a lifting mechanism 33 that lifts the arm 31 in the vertical direction. Then, the transfer unit 30 transfers the wafer W to the transfer position A0 of the grinding unit 40, the alignment unit 50, the first cleaning unit 60, and the second cleaning unit 70. It is configured to be transportable.

A rotary table 41 is provided in the grinding unit 40 . On the rotation table 41, four chucks 42 are provided to adsorb and hold the wafer W. For example, a porous chuck is used for the chuck 42 , and the surface Wa (protective tape T) of the wafer W is adsorbed and held. When viewed from the side, 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 addition, although the protrusion of this central part is minute, in the illustration below, the protrusion of the central part of the chuck 42 may be shown large for clarification of explanation.

As shown in FIG. 3 , the chuck 42 is held by the chuck base 43 . In the chuck base 43, an inclination adjusting mechanism 44 for adjusting the relative inclination of each grinding part (coarse grinding part 80, intermediate grinding part 90 and finish grinding part 100) and the chuck 42 is provided. It is provided. The inclination adjustment mechanism 44 may incline the chuck 42 and the chuck base 43, thereby adjusting the relative inclination between various grinding parts at the processing positions A1 to A3 and the upper surface of the chuck 42. there is. In addition, the configuration of the inclination adjustment mechanism 44 is not particularly limited, and can be arbitrarily selected as long as the angle (parallelism) of the chuck 42 relative to the grindstone can be adjusted.

The four chucks 42 can be moved to the delivery position A0 and the processing positions A1 to A3 when the rotary table 41 rotates. Further, each of the four chucks 42 is configured to be rotatable around a vertical axis by a rotation mechanism (not shown).

At the transfer position A0, transfer of the wafer W by the transfer unit 30 is performed. A rough grinding unit 80 is disposed at the processing position A1 to rough grind the wafer W. An intermediate grinding unit 90 is disposed at the processing position A2 to perform intermediate grinding of the wafer W. A finish grinding unit 100 is disposed at the processing position A3 to finish grind the wafer W.

The coarse grinding unit 80 includes a coarse grinding wheel 81 having an annular rough grinding stone on its lower surface, a mount 82 supporting the coarse grinding wheel 81, and the mount 82. It has a spindle 83 which rotates the coarse grinding wheel 81 through the intervening, and a driving part 84 incorporating, for example, a motor (not shown). Moreover, along the support|pillar 85 shown in FIG. 2, the rough grinding part 80 is comprised so that a movement in a vertical direction is possible.

The intermediate grinding section 90 has the same configuration as the coarse grinding section 80 . That is, the intermediate grinding unit 90 has an intermediate grinding wheel 91 provided with an annular intermediate grinding wheel, a mount 92, a spindle 93, a drive unit 94, and a post 95. The grain size of the abrasive grain of the intermediate grinding wheel is smaller than that of the coarse grinding wheel.

The finish grinding unit 100 has the same configuration as the rough grinding unit 80 and the intermediate grinding unit 90 . That is, the finish grinding unit 100 includes a finish grinding wheel 101 having an annular finish grinding wheel, a mount 102, a spindle 103, a drive unit 104, and a support post 105. The grain size of the abrasive grain of the finishing grinding wheel is smaller than that of the intermediate grinding stone.

In addition, thickness measurement units for measuring the thickness of the wafer W during the grinding process are provided at the delivery position A0 and the processing positions A1 to A3 of the grinding unit 40 . Specifically, as shown in FIG. 2, a contact-type thickness measuring mechanism (hereinafter referred to as 'contact-type measuring mechanism 110') is provided at the processing positions A1 and A2, and the transfer position A0 and the processing A non-contact type thickness measuring device (hereinafter, referred to as 'non-contact measuring device 120') is provided at the positions A2 and A3, respectively.

As shown in FIG. 4 , the contact type measuring mechanism 110 includes a height gauge 111 on the chuck side, a height gauge 112 on the wafer side, and a calculator 113 . The height gauge 111 includes a probe 114, and when the tip of the probe 114 contacts the surface of the chuck 42, that is, the holding surface of the wafer W, the height position of the holding surface is measured. The height gauge 112 includes a probe 115, and the front end of the probe 115 contacts the back surface Wb, which is the processing surface of the wafer W, to measure the height position of the back surface Wb. The calculator 113 calculates the total thickness of the wafer W by subtracting the measured value of the height gauge 111 from the measured value of the height gauge 112 . The total thickness of the wafer W is the thickness of the main body of the wafer W plus the thickness of the device D and the thickness of the protective tape T. In addition, the thickness measurement range of the wafer W by the contact measuring mechanism 110 is, for example, 0 to 2000 μm.

In addition, in this way, the contact measuring mechanism 110 makes the height gauges 111 and 112 contact the surface of the chuck 42 and the back surface Wb of the wafer W, thereby calculating the overall thickness of the wafer W do. However, the thickness data calculated by the contact measuring mechanism 110 is not limited to this total thickness. For example, when the thicknesses of the protective tape T and the device D are known, from the measured total thickness The body thickness of the wafer W may be calculated by further subtracting the thicknesses of the protective tape T and the device D.

The non-contact measurement mechanism 120 has a sensor 121 and a calculator 122 as shown in FIG. 5 . As the sensor 121, a sensor that measures the thickness of the main body of the wafer W without contacting the wafer W is used, for example, a white confocal type optical sensor is used. The sensor 121 radiates light having a predetermined wavelength band to the wafer W, and receives the reflected light reflected from the front surface Wa of the wafer W and the reflected light reflected from the back surface Wb of the wafer W. The calculator 122 calculates the body thickness of the wafer W as pulse data based on both the reflected lights received by the sensor 121 . In addition, the thickness measurement range of the wafer W by the non-contact measuring mechanism 120 is, for example, 5 to 300 μm.

In addition, the configurations of the contact measurement mechanism 110 and the non-contact measurement mechanism 120 are not limited to the present embodiment, and may take any configuration. For example, in the present embodiment, a white confocal type optical sensor is used for the sensor 121 of the non-contact measurement mechanism 120, but the configuration of the non-contact measurement mechanism 120 is not limited to this, and the Any measuring instrument can be used as long as the body thickness is measured in a non-contact manner. In addition, a plurality of sensors 121 may be provided. Also, the light emitted from the sensor 121 is not particularly limited, and may be pulsed light or continuous light as long as it can be received by the sensor 121 as reflected light.

In this embodiment, both the contact type measuring mechanism 110 and the non-contact measuring mechanism 120 are provided as a thickness measurement part at processing position A2 as mentioned above. Then, at the processing position A2, as will be described later, the thickness measuring unit is switched according to the thickness of the wafer W under grinding and the state of the processing surface (back surface Wb), that is, from the contact measuring mechanism 110. A switch to the non-contact measurement mechanism 120 is performed. Details of the switching operation of the thickness measurement unit will be described later.

The above processing device 1 is provided with a control unit 130 . The control unit 130 is, for example, a computer equipped with a CPU, memory, and the like, and has a program storage unit (not shown). A program for controlling processing of the wafer W in the processing device 1 is stored in the program storage unit. Moreover, the program which controls the switching operation|movement of the thickness measuring part in the process position A2 mentioned above is further stored in the program storage part. In addition, the program may have been recorded in a computer-readable storage medium H, and may have been installed in the control unit 130 from the storage medium H.

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

First, the cassette C, in which a plurality of wafers W are stored, is placed on the cassette placing table 10 of the carry-in/out station 2 . Next, the wafer W is taken out of the cassette C by the transfer fork 23 of the wafer transfer device 22 and transferred to the alignment unit 50 of the processing station 3 . In the alignment unit 50, the horizontal direction of the wafer W is adjusted by adjusting the position of a notch portion (not shown) formed on the wafer W.

The wafer W whose horizontal direction has been adjusted is then transported from the alignment unit 50 by the transfer unit 30 and transferred to the chuck 42 at the transfer position A0. Subsequently, the rotary table 41 is rotated to sequentially move the chuck 42 to the processing positions A1 to A3, and various grinding processes (rough grinding, intermediate grinding, and finish grinding) are performed on the back surface of the wafer W. Conduct. In addition, various types of grinding processing in the grinding unit 40, as described above, in order to grind the wafer W to a desired thickness, the thickness measuring unit (the contact measuring mechanism 110 and the non-contact measuring mechanism 120) It is performed while measuring the thickness of the wafer W using

Various grinding processes in the grinding unit 40 and a method for measuring the thickness of the wafer W will be described in detail.

At the processing position A1, as shown in FIG. 6, the probe 114 of the height gauge 111 of the contact type measuring mechanism 110 is placed on the surface of the chuck 42 and the probe 115 of the height gauge 112 is placed. The back surface Wb of the wafer W is rough-ground using the rough grinding unit 80 in a state where the back surface Wb of the wafer W is brought into contact with each other. As described above, when measuring the thickness of the wafer W, the back surface Wb of the wafer W is not damaged, and the wafer excluding the thickness of the device D and the protective tape T ( W) It is preferable to use a non-contact measuring instrument 120 capable of measuring its own thickness. However, the non-contact measurement mechanism 120 has a narrower range for measuring the thickness of the wafer W compared to the contact measurement mechanism 110, and cannot measure the thickness of the wafer W immediately after being carried into the grinding unit 40. . Therefore, in the rough grinding treatment at the processing position A1, the thickness of the wafer W is up to a thickness that can be measured (for example, 5 to 300 μm) by the non-contact measuring mechanism 120, for example. reduces

When the wafer W is rough-ground to a desired thickness, the rotation table 41 is rotated to move the chuck 42 (wafer W) to the processing position A2.

At the processing position A2, first, while measuring the thickness of the wafer W using the contact measuring mechanism 110, the back surface Wb of the wafer W is intermediately ground using the intermediate grinding unit 90, , and then, in the middle of this intermediate grinding, the thickness measuring unit is switched from the contact measuring mechanism 110 to the non-contact measuring mechanism 120. As described above, it is preferable to use the non-contact measuring mechanism 120 to measure the thickness of the wafer W, but when the non-contact measuring mechanism 120 is used in a state where the roughness of the back surface Wb immediately after rough grinding is large, There is a possibility that the reflected light from the back surface Wb is non-uniform, and stable measurement results cannot be obtained.

Therefore, in the present embodiment, at the processing position A2, the thickness measurement of the wafer W by the contact measuring mechanism 110 and the thickness measurement by the non-contact measuring mechanism 120 are possible at the beginning of the intermediate grinding process The determination of (hereinafter, referred to as 'measurable determination' of the non-contact measuring instrument 120) is performed in parallel. Then, if it is determined that the roughness of the back surface Wb after rough grinding is improved (pre-grinding process) by the progress of the intermediate grinding process, and the thickness measurement by the non-contact measuring mechanism 120 can be appropriately performed, the non-contact measuring mechanism ( 120) starts measuring the thickness, and then, the thickness measurement using the contact type measuring instrument 110 ends.

Specifically, in the processing position A2 of the processing device 1 according to the present embodiment, as shown in FIG. While measuring the thickness by the measuring mechanism 110, the back surface Wb of the wafer W is subjected to intermediate grinding (process P1 in FIG. 8 ). 8(a) shows an example of the result of measuring the thickness of the wafer W in each of the contact measuring mechanism 110 and the non-contact measuring mechanism 120 at the processing position A2. Fig. 8(b) shows details of an example of the measurement results of the non-contact measurement mechanism 120 in Fig. 8(a).

When the thickness of the wafer W is reduced to a desired thickness for improving the roughness of the back surface Wb, then, as shown in FIG. While continuing the thickness measurement by 110), the measurable determination of the non-contact measuring mechanism 120 is started (process (P2) of FIG. 8). The measurable determination of the non-contact measurement mechanism 120 is the main body of the wafer W, which is calculated based on the light emitted from the sensor 121 and the reflected light from the front surface Wa and the back surface Wb of the wafer W. This is done using pulse data of the thickness. Specifically, for example, as shown in FIG. 8 , one body thickness data d(n) calculated in the calculator 122 and another body thickness data d(n-1) calculated immediately before When the difference value of ) enters within a predetermined threshold value consecutively a plurality of times, it is determined that accurate thickness measurement by the non-contact measuring mechanism 120 has become possible. In other words, when the variation over time of the continuously calculated body thickness data becomes smaller, it is determined that the body thickness measured by the non-contact measurement mechanism 120 is reliable data as the measurement result, and the non-contact measurement mechanism 120 determines It is judged that accurate thickness measurement became possible.

In the present embodiment, after the roughness of the back surface Wb is improved by intermediate grinding in this way, measurable determination of the non-contact measuring mechanism 120 is performed. When the measurable determination is started in a state in which the illuminance of the back surface Wb is high, as described above, the reflected light of the non-contact measuring mechanism 120 (thickness data to be measured) is uneven, and a stable measurable determination cannot be made. That is, for example, non-uniformity occurs in the measured thickness data, the measured thickness data accidentally falls within the threshold, and accurate thickness measurement is possible at a time when accurate thickness measurement by the non-contact measuring mechanism 120 cannot be performed. There is a risk of misjudgment. In this respect, by improving the illuminance of the back surface Wb in this way and making measurable determination after the unevenness of the measured thickness data is reduced, the risk of occurrence of misjudgment in this measurable determination can be reduced.

In addition, by determining whether or not the measured thickness data falls within the threshold, as described above, when it is continuously entered a plurality of times, the risk of occurrence of erroneous judgment in such measurable determination can be more appropriately reduced. .

In addition, as the data used as the threshold used for the determination, for example, the grinding amount of the wafer W per measurement cycle by the non-contact measuring mechanism 120 by the descending speed of the grinding wheel of the intermediate grinding unit 90, etc. available. In this case, the threshold value used is, for example, the grinding amount of the wafer W per measurement cycle +/- 1 µm.

However, the data used as the threshold is not limited to this "amount of grinding per measurement cycle", and any data can be used as the threshold, and the data value used as the threshold can, of course, be any value. For example, the measurable determination may be made by comparing the measured value of the thickness by the non-contact measuring instrument 120 with the measured value of the thickness by the contact-type measuring instrument 110. In other words, the measurement result of the thickness of the wafer W by the contact measuring mechanism 110 may be used as the threshold value.

Also, the number of consecutive times that the difference value falls within the threshold value for determining that measurement by the non-contact measuring instrument 120 has become possible is not particularly limited, and can be determined as an arbitrary number of times of two or more. However, from the viewpoint of reducing the risk of occurrence of erroneous judgment in measurable determination as described above, it is preferable that the number of continuations is larger.

If it is determined that the measurement by the non-contact measurement mechanism 120 has become possible, the measurable determination processing is ended, and use of the thickness data calculated by the non-contact measurement mechanism 120 as the thickness of the wafer W is started. Then, when the thickness measurement by the non-contact measuring mechanism 120 is started, thereafter, as shown in FIG. The thickness measurement of ) is stopped (process (P3) in FIG. 8), whereby the thickness measurement unit at the processing position A2 is switched from the contact type measuring mechanism 110 to the non-contact measuring mechanism 120.

In addition, when it is determined that measurement by the non-contact measuring mechanism 120 is impossible in the measurable determination, that is, when the unevenness over time of the continuously calculated body thickness data does not become small, the thickness measuring unit is not switched, Intermediate grinding of the wafer W continues. When the thickness measurement unit cannot be switched in this way, an error may be issued immediately after the intermediate grinding process of the wafer W is finished, or the grinding process may be continued using the contact measuring mechanism 110 .

When the thickness measuring part is switched from the contact measuring mechanism 110 to the non-contact measuring mechanism 120, the intermediate grinding process in the process position A2 is further continued after that. Then, when the wafer W is intermediately ground to a target thickness, it is detected as an end point, and the grinding transfer and grinding of the intermediate grinding unit 90 are terminated. After that, the rotary table 41 is rotated to move the chuck 42 (wafer W) to the processing position A3.

At the processing position A3, as shown in FIG. 9, while measuring the body thickness of the wafer W by the non-contact measuring mechanism 120, the back surface Wb of the wafer W is measured using the finish grinding unit 100. finish grinding. At the processing position A3, the thickness of the wafer W is sufficiently reduced in the rough grinding section 80 and the intermediate grinding section 90, and the roughness of the back surface Wb is improved, so appropriate non-contact measurement Thickness measurement by the instrument 120 can be performed.

When the finish grinding process of the wafer W is completed, next, the rotary table 41 is rotated to move the chuck 42 to the delivery position A0. At the delivery position A0, while rotating the wafer W, the non-contact measuring mechanism 120 measures the body thickness of a plurality of points including the vicinity of the central portion and the vicinity of the periphery of the wafer W, thereby measuring the wafer ( W) of flatness (TTV: Total Thickness Variation) is calculated.

Subsequently, the wafer W is transported from the delivery position A0 by the transport unit 30 to the second cleaning unit 70, and the surface Wa of the wafer W is moved while being held by the transport pad 32. this is cleaned

Next, the wafer W is transported from the second cleaning unit 70 to the first cleaning unit 60 by the transfer unit 30, and a cleaning liquid nozzle (not shown) is used to clean the wafer W. The front surface Wa and the back surface Wb are cleaned.

Thereafter, the wafer W having all the processes performed is transported to the cassette C of the cassette placing table 10 by the transport fork 23 of the wafer transport device 22 . In this way, a series of wafer processing in the processing device 1 ends.

As described above, according to the wafer processing according to the present embodiment, after it is determined that accurate thickness measurement by the non-contact measuring mechanism 120 is possible in the measurable determination, the wafer W of calculated data by the non-contact measuring mechanism 120 The use of the thickness of is started, and then the thickness measuring unit is switched from the contact type measuring mechanism 110 to the non-contact measuring mechanism 120. For this reason, it is possible to stably continue measuring the thickness of the wafer W when the thickness measuring unit is switched.

In addition, at this time, in the measurable decision, when the difference value of the main body thickness data continuously acquired by the non-contact measuring device 120 falls within the threshold value consecutively a plurality of times, the non-contact measuring device 120 accurately measures the thickness. determine that this is possible. In this way, whether or not accurate thickness measurement by the non-contact measuring mechanism 120 is possible is determined after the difference value of the body thickness data has entered the threshold multiple times in succession, resulting in misjudgment of measurable determination due to non-uniformity of the measurement data. The risk of justice occurring can be reduced. That is, operation switching from the contact measuring device 110 to the non-contact measuring device 120 can be appropriately performed after the body thickness measured by the non-contact measuring device 120 is determined to be reliable data as a measurement result. there is.

In the present embodiment, the measurable determination is started after the roughness of the back surface Wb is improved by intermediate grinding of the wafer W. In this way, the risk of misjudgment in determining whether the non-contact measurement mechanism 120 can be measured can be reduced, that is, the operation can be switched from the contact type measurement mechanism 110 to the non-contact measurement mechanism 120 more appropriately. .

Moreover, according to this embodiment, the switching operation of the above thickness measurement part can be performed automatically based on the measured pulse data without intervening the operation by an operator. Thereby, generation|occurrence|production of the malfunction accompanying an operator's operation can be suppressed, and also the throughput accompanying the grinding process in the processing apparatus 1 can be improved suitably.

Further, in the above embodiment, after improving the roughness of the back surface Wb of the wafer W, the measurement of the thickness of the wafer W for determining the measurability of the non-contact measuring mechanism 120 is started, but this wafer ( The thickness measurement of W) may be started simultaneously with the intermediate grinding treatment. In addition, the measurable determination may be started simultaneously with the intermediate grinding process. Even in such a case, the thickness measurement of the wafer W by the non-contact measurement mechanism 120 is started after the difference value of the main body thickness data obtained by the non-contact measurement mechanism 120 is within the threshold value for a plurality of consecutive times. It is possible to switch the thickness measurement part in an easy way.

Further, in the above embodiment, the thickness of the wafer W is reduced to the thickness measurement range (for example, 5 to 300 μm) of the non-contact measuring mechanism 120 by the rough grinding part 80 at the processing position A1. After that, the wafer W was moved to the processing position A2. However, the thickness of the wafer W introduced into the processing position A2 is not limited thereto, and is larger than the thickness measurement range of the non-contact measurement mechanism 120 (for example, greater than 300 μm), and the wafer W may be thrown into the processing position A2. In this case, after reducing the thickness of the wafer W to the thickness measuring range of the non-contact measuring device 120 by the intermediate grinding unit 90 at the processing position A2 (pre-grinding process), the non-contact measuring device 120 Initiates a measurable determination of

In the above embodiment, the case where the grinding unit 40 has a 3-axis configuration (rough grinding unit 80, intermediate grinding unit 90, and finish grinding unit 100) has been described as an example, but the grinding process As long as it requires a switching operation of the thickness measuring unit, the configuration of the grinding unit 40 is not limited thereto. For example, the grinding unit may have a two-axis configuration in which only the rough grinding unit 80 (or intermediate grinding unit 90) and the finish grinding unit 100 are provided, or may have a single-axis configuration in which only one grinding unit is provided.

Further, in the above embodiment, the case where the back surface Wb of the wafer W is subjected to a grinding process in the grinding unit 40 of the processing device 1 to thin it has been described as an example, but the wafer W The thinning method is not limited thereto. Specifically, as shown in FIG. 10(a), the modified layer M is formed by irradiating laser light (eg, YAG laser) into the inside of the wafer W, and as shown in FIG. 10(b) Likewise, even when the wafer W is separated and thinned using the modified layer M as a starting point, the technique according to the present disclosure can be applied. In this way, when the separation of the wafer W is performed with the modified layer M as the starting point, the separation surface of the wafer W has high roughness due to the influence of the remaining modified layer M (damage layer), and the non-contact measurement mechanism There is a possibility that the thickness measurement by (120) cannot be performed accurately. Therefore, as shown in (c) of FIG. 10 , in the grinding process for removing the damage layer, first, while measuring the thickness by the contact measuring mechanism 110, it is determined that the non-contact measuring mechanism 120 can measure the measurement. and after improving the roughness of the separation surface (after removing the damage layer), switching to the non-contact measuring mechanism 120 is performed.

In the above embodiment, light is irradiated from the sensor 121 of the non-contact measurement mechanism 120, and based on pulse data calculated based on reflected light from the wafer W of the light, measurable determination is made. However, data used for measurable determination is not limited to pulse data, and measurable determination may be made based on continuous data calculated by reflected light of continuous light, for example. In this case, the measurable determination is made so that the calculated body thickness data continues to fall within the threshold at a desired time, instead of using for determining whether or not the difference value of the body thickness data has entered the threshold a plurality of times consecutively as in the above embodiment. It can be used to determine whether or not it has been entered.

In the above embodiment, as shown in FIG. 1 , the case where the wafer W as the substrate is a short wafer having the device D and the protective tape T on the surface Wa is described as an example, but the wafer The configuration of (W) is also not limited to the above embodiment. Specifically, the technique according to the present disclosure can be applied even when the first wafer is thinned in a polymerized wafer in which a first wafer having devices formed thereon and a second wafer are bonded to each other.

It should be thought that the embodiment disclosed this time is not limited to an example at all points. The embodiments described above may be omitted, substituted, or changed in various forms without departing from the scope of the appended claims and their main points.

1: processing device
40: grinding part
110: contact measuring instrument
120: non-contact measuring mechanism
130: control unit
W: Wafer
Wb: back side

Claims (14)

A substrate processing system for processing a substrate,
a grinding unit for grinding the processing surface of the substrate;
A thickness measurement unit for measuring the thickness of the substrate;
Has a control unit for controlling the operation of the thickness measuring unit,
The thickness measuring unit,
a contact measuring mechanism for contacting the processing surface of the substrate to measure the thickness of the substrate;
A non-contact measuring mechanism for measuring the thickness of the substrate in a non-contact manner with the substrate,
The control unit,
In the grinding process of the substrate by the grinding unit, performing control of the thickness measuring operation of the substrate by the contact measuring mechanism and controlling of the measurable determination operation by the non-contact measuring mechanism are performed in parallel, ,
In the control of the measurable determination operation,
calculating a difference value between one thickness measurement value obtained by the non-contact measurement mechanism and another thickness measurement value obtained immediately before the one thickness measurement value successively over time;
When the calculated difference values continuously fall within a predetermined threshold value, it is determined that the thickness measurement of the substrate is possible, and control is performed to start a thickness measurement operation of the substrate by the non-contact measurement mechanism. According to claim 1,
The control unit performs control to stop the thickness measurement operation by the contact measurement mechanism by separating the contact measurement mechanism from the processing surface after the start of the thickness measurement operation by the non-contact measurement mechanism, the substrate processing system . According to claim 1 or 2,
The control unit performs control using a result of measuring the thickness of the substrate by the contact-type measuring mechanism as the threshold value. According to any one of claims 1 to 3,
The control unit,
The substrate processing system of claim 1 , wherein an operation of the grinding unit is controlled so that the grinding unit performs a pre-grinding process of the machined surface prior to a measurable determination operation by the non-contact measuring mechanism. According to claim 4,
The control unit controls an operation of the thickness measurement unit to perform a thickness measurement operation of the substrate by the contact measurement mechanism in the pre-grinding process. According to claim 4 or 5,
In the pre-grinding process, the processing surface of the substrate having a thickness within a detection range by the non-contact measuring mechanism is ground to a predetermined thickness, and the roughness of the processing surface is improved. According to claim 4 or 5,
In the pre-grinding process, the processed surface of the substrate having a thickness outside the detection range by the non-contact measuring mechanism is ground until the thickness of the substrate reaches within the detection range. As a substrate processing method for processing a substrate,
grinding the processing surface of the substrate;
In parallel with the grinding of the processing surface, measuring the thickness of the substrate using a contact measuring instrument;
judging whether or not the thickness of the substrate can be measured by a non-contact measurement mechanism in parallel with the grinding of the machined surface and the thickness measurement by the contact measurement mechanism;
Initiating thickness measurement of the substrate by the non-contact measurement mechanism based on a measurable determination result of the non-contact measurement mechanism,
In the measurable determination of the non-contact measurement mechanism,
calculating a difference value between one thickness measurement value obtained by the non-contact measurement mechanism and another thickness measurement value obtained immediately before the one thickness measurement value successively over time;
The substrate processing method of determining that the thickness of the substrate can be measured when the calculated difference values continuously fall within a predetermined threshold value. According to claim 8,
and stopping the thickness measurement of the substrate by the contact-type measurement mechanism after starting the measurement of the thickness of the substrate by the non-contact measurement mechanism. According to claim 8 or 9,
A substrate processing method using a result of measuring the thickness of the substrate by the contact-type measuring mechanism as the threshold value. According to any one of claims 8 to 10,
Performing a pre-grinding process on the machined surface prior to the measurable determination of the non-contact measuring mechanism,
In the pre-grinding treatment of the processing surface, the thickness of the substrate is measured by the contact measuring mechanism. According to claim 11,
In the pre-grinding process, the processed surface of the substrate having a thickness within a detection range by the non-contact measuring mechanism is ground to a predetermined thickness to improve the roughness of the processed surface. According to claim 11,
In the pre-grinding process, the processed surface of the substrate having a thickness outside the detection range by the non-contact measuring mechanism is ground until the thickness of the substrate reaches within the detection range. A readable computer storage medium storing a program operating on a computer of a control unit for controlling a substrate processing system so that a substrate processing method for processing a substrate is executed by the substrate processing system,
The substrate processing system,
a grinding unit for grinding the processing surface of the substrate;
A thickness measurement unit for measuring the thickness of the substrate;
Has a control unit for controlling the operation of the thickness measuring unit,
The thickness measuring unit,
a contact measuring mechanism for contacting the processing surface of the substrate to measure the thickness of the substrate;
A non-contact measuring mechanism for measuring the thickness of the substrate in a non-contact manner with the substrate,
The substrate processing method,
grinding the processing surface of the substrate;
In parallel with the grinding of the processing surface, measuring the thickness of the substrate using a contact measuring instrument;
judging whether or not the thickness of the substrate can be measured by a non-contact measurement mechanism in parallel with the grinding of the machined surface and the thickness measurement by the contact measurement mechanism;
Initiating thickness measurement of the substrate by the non-contact measuring mechanism based on a measurable determination result of the non-contact measuring mechanism,
In the measurable determination of the non-contact measurement mechanism,
calculating a difference value between one thickness measurement value obtained by the non-contact measurement mechanism and another thickness measurement value obtained immediately before the one thickness measurement value successively over time;
and determining that the thickness of the substrate can be measured when the calculated difference values continuously fall within a predetermined threshold value.

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