Wafer processing method and processing apparatus

Abstract

To quickly dry a liquid resin supplied to the upper surface of a wafer, and efficiently form a protective film having necessary and sufficient thickness on the upper surface of the wafer in short time.SOLUTION: A wafer processing method includes a wafer holding step of holding the rear face of a wafer W by a holding table 51, a resin supply step of supplying a liquid resin onto the surface of the wafer W, a protective film formation step of drying the liquid resin f with light emitted from a xenon flash lamp (light source) 61, and forming a protective film F on the surface of the wafer W, wherein air (gas) heated by the xenon flash lamp 61 in the protective film formation step is supplied to a processing chamber S2 where the protective film formation step is performed, the air is discharged to the outside from the processing chamber S2, and thereby drying of the liquid resin f is promoted by the air.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for processing a wafer, which form a protective film on the upper surface of the wafer before laser processing the wafer.

Background Art

[0002] For example, in the manufacturing process of semiconductor devices, the surface of a semiconductor wafer (hereinafter simply referred to as "wafer") is partitioned into a number of rectangular regions by dividing lines to be formed (hereinafter referred to as "streets") arranged in a grid pattern, and devices such as ICs and LSIs are formed in each rectangular region. Then, laser processing is performed in which a laser beam is irradiated along the street on the surface of the wafer on which such a large number of devices are formed to form grooves on the surface, and the wafer is divided along the grooves to obtain individual semiconductor chips.

[0003] By the way, when a wafer is laser processed, fine dust called debris is generated in the portion of the wafer irradiated with the laser beam, and this dust scatters around and adheres to the surface of the device, causing a problem of deteriorating the quality of the device.

[0004] Therefore, Patent Document 1 proposes a method for processing a wafer in which a protective film is previously formed on the surface of the wafer, and then laser processing is performed, and the debris adhering to the protective film is washed and removed together with the protective film. In this processing method, after a water-soluble liquid resin constituting the protective film is supplied to the surface of the wafer, the wafer is rotated in the circumferential direction to dry the liquid resin, thereby forming a required protective film.

[0005] Incidentally, when a laser beam is shone onto the surface of a wafer on which a protective film has been formed, as described above, a plasma of the elements constituting the wafer is excited near the surface of the wafer. When the plasma is excited in this way, the protective film is exposed to the plasma, and if the protective film is thin, the wafer may be plasma-etched and damaged. For this reason, it is desirable to form the protective film to a thickness that can withstand the plasma.

[0006] However, the method of drying the liquid resin by rotating the wafer circumferentially, as proposed in Patent Document 1, has the problem of poor productivity because it takes a long time to form the protective film to the required thickness. Furthermore, with such a method, it is difficult to thoroughly dry the inside of the protective film. In particular, in wafers with bumps (metal electrodes) on the surface of the device, the protective film needs to be formed to a thickness sufficient to cover the top of the bumps, so the thickness of the protective film inevitably becomes thicker, and the time required to dry the liquid resin becomes even longer.

[0007] Therefore, Patent Document 2 proposes a method for forming a protective film by drying a liquid resin supplied to the surface of a wafer in a short time by irradiating it with light from a light source such as a xenon flash lamp. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2006-140311 [Patent Document 2] Japanese Patent Publication No. 2017-034008 [Overview of the project] [Problems that the invention aims to solve]

[0009] However, in the method proposed in Patent Document 2, if water vapor generated by the evaporation of water contained in the liquid resin accumulates in the processing chamber that houses the wafer held on the holding table and the liquid resin supply unit that supplies the liquid resin to the wafer, the water vapor pressure in the processing chamber increases, making it difficult for the water contained in the liquid resin to evaporate. Furthermore, because the water vapor in the processing chamber absorbs the light irradiated from the light source, the heating of the liquid resin by light is not performed effectively, resulting in slow drying of the liquid resin and requiring a relatively long time to form the protective film.

[0010] The present invention has been made in view of the above problems, and its object is to provide a wafer processing method and processing apparatus that can quickly dry a liquid resin supplied to the upper surface of a wafer and efficiently form a protective film of sufficient thickness on the upper surface of the wafer in a short time. [Means for solving the problem]

[0012] The wafer processing apparatus according to the present invention comprises a processing chamber housing a holding table for holding wafers and a resin supply unit for supplying liquid resin to wafers held on the holding table; a light source for irradiating the liquid resin supplied to the wafer from the resin supply unit with light to dry the liquid resin and form a protective film on the surface of the wafer; a light source housing for housing the light source; a gas supply source for supplying gas into the light source housing; a supply path that connects the light source housing and the processing chamber and supplies heated gas that has passed through the light source housing to the processing chamber; and an exhaust port for discharging heated gas from the processing chamber to the outside, wherein the drying of the liquid resin is accelerated by the heated gas supplied to the processing chamber through the supply path. [Effects of the Invention]

[0013] According to the present invention, in the protective film formation step, the light source is cooled in the light source housing, and the heated gas, whose temperature has risen, flows into the processing chamber through the supply passage. The water vapor generated by the drying of the supplied liquid resin formed on the wafer surface is discharged outside the processing chamber along with the heated gas. As a result, the vapor pressure inside the processing chamber decreases, promoting the drying of the liquid resin (evaporation of moisture), and suppressing the absorption of light irradiated from the light source into water vapor. Therefore, the light from the light source is efficiently irradiated onto the liquid resin, heating the liquid resin, which also promotes the drying of the liquid resin. As a result, the liquid resin dries and solidifies quickly, and a protective film of sufficient thickness is efficiently formed on the upper surface of the wafer in a short time, thereby increasing productivity.

[0014] Furthermore, by effectively utilizing the heat from the heated gas and using this heat to heat the processing chamber, the drying of the liquid resin can be accelerated, allowing for the formation of a protective film of sufficient thickness on the upper surface of the wafer in an even shorter and more efficient manner.

[0015] Furthermore, the light source housed in the light source housing is effectively cooled by the gas introduced into the light source housing from the gas supply source, suppressing its temperature rise. As a result, the light source maintains high luminous efficiency and ensures high durability. [Brief explanation of the drawing]

[0016] [Figure 1] This is a perspective view of a laser processing apparatus, which is a wafer processing apparatus according to the present invention. [Figure 2] This is a perspective view of the wafer. [Figure 3] This is an enlarged cross-sectional view along line AA in Figure 2. [Figure 4] This flowchart shows the procedure for the wafer processing method according to the present invention. [Figure 5] This is a longitudinal cross-sectional view of a cleaning unit showing the holding table heating step in the wafer processing method according to the present invention. [Figure 6] This is a longitudinal cross-sectional view of a cleaning unit showing the wafer holding step in the wafer processing method according to the present invention. [Figure 7] It is a longitudinal sectional view of a cleaning unit showing the resin supply step in the method for processing a wafer according to the present invention. [Figure 8] It is a longitudinal sectional view of a cleaning unit showing the protective film forming step in the method for processing a wafer according to the present invention. [Figure 9] It is a longitudinal sectional view of the main part of a wafer on which a protective film is formed in the protective film forming step. [Figure 10] It is a partial longitudinal sectional view showing the state of the processed part of the wafer in the laser beam irradiation step in the method for processing a wafer according to the present invention. [Figure 11] It is a longitudinal sectional view of a cleaning unit showing the cleaning step in the method for processing a wafer according to the present invention. [Figure 12] It is a longitudinal sectional view showing another form of the cleaning unit of the laser processing apparatus. [[ID= XIX]]

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described based on the accompanying drawings.

[0018] [Configuration of Laser Processing Apparatus] First, the basic configuration of a laser processing apparatus as one form of the wafer processing apparatus according to the present invention will be described based on FIG. 1. In the following description, the directions of the arrows shown in FIG. 1 are defined as the X-axis direction (left - right direction), Y-axis direction (front - back direction), and Z-axis direction (up - down direction), respectively.

[0019] The laser processing apparatus 1 shown in Figure 1 is a device for laser processing a thin, disc-shaped wafer W shown in Figure 2, and is a device that forms a protective resin film F (see Figure 9) on the surface of the wafer W before laser processing. The laser processing apparatus 1 mainly comprises a chuck table 10 for holding the wafer W, a laser beam irradiation unit 20 for laser processing the wafer W held on the chuck table 10, a first transport means 30 and a second transport means 40 for transporting the wafer W, and a cleaning unit 50 that forms a protective film F on the surface of the wafer W before laser processing and cleans the wafer W after laser processing to remove the protective film F from the surface of the wafer W.

[0020] In addition, the laser processing apparatus 1 shown in Figure 1 includes a cassette 70 placed on a cassette elevator (not shown), a temporary storage section 80 located near the cassette 70, and a loading / unloading means 90 for loading and unloading wafers W into and out of the cassette 70. The temporary storage section 80 is equipped with a pair of rails 81 arranged parallel to each other along the Y-axis.

[0021] Here, the workpiece, wafer W, is composed of a single-crystal silicon matrix, and as shown in Figure 2, multiple streets L are formed in a grid pattern on its surface. Devices D are formed in multiple rectangular regions demarcated by the multiple streets L of wafer W. Furthermore, as shown in Figures 2 and 3, multiple bumps (metal electrodes) BP are provided protruding from the surface of each device D. The bumps BP are composed of noble metals such as gold (Au) and platinum (Pt), or alloys such as tin (Sn)-copper (Cu).

[0022] Next, the configurations of the main components constituting the laser processing apparatus 1—the chuck table 10, the laser beam irradiation unit 20, the first transport means 30 and the second transport means 40, and the cleaning unit 50—will be described in order below.

[0023] (Chuck table) As shown in Figure 1, the chuck table 10 is a disc-shaped member, and its upper surface constitutes a holding surface 10a that supports the wafer W. This chuck table 10 is movable along its longitudinal direction (X-axis direction) between the processing position P1 and the transfer position P2 by an X-axis moving means (not shown), and is also supported so as to be rotatable around a vertical axis. The chuck table 10 is rotated at a predetermined speed around a vertical central axis by a drive mechanism (not shown).

[0024] (Laser beam irradiation unit) As shown in Figure 1, a support base 3 is erected on the left end (-X axis direction end) of the base 2 of the laser processing apparatus 1, and a laser beam irradiation unit 20 is supported on this support base 3. This laser beam irradiation unit 20 is positioned above the chuck table 10 that moves to the processing position P1 at the processing position P1, and includes an oscillator 21 that emits a laser beam, and a laser head 22 that focuses the laser beam emitted by the oscillator 21 using a light condenser (not shown) and emits it.

[0025] Here, the oscillator 21 emits a laser beam with a wavelength absorbed by the wafer W, and the frequency of the emitted laser beam can be arbitrarily adjusted according to the type of wafer W and the processing method. The oscillator 21 can be a YAG laser oscillator or a YVO oscillator, among others. Furthermore, a light concentrator (not shown) built into the laser head 22 includes a total reflection mirror that changes the direction of propagation of the laser beam emitted by the oscillator, and a focusing lens that concentrates the laser beam.

[0026] Furthermore, as shown in Figure 1, the imaging unit 23 is supported at the bottom of the support base 3.

[0027] The laser beam irradiation unit 20 configured as described above can be indexed in the Y-axis direction (front-to-back direction) by a Y-axis moving means (indexing means) not shown, and can be raised and lowered in the Z-axis direction (cutting direction of the groove 100 (see Figure 10)) by a Z-axis moving means (lifting means) not shown. The Y-axis moving means and the Z-axis moving means (lifting means) are configured by well-known ball screw mechanisms or the like.

[0028] By the way, in the laser processing apparatus 1 according to this embodiment, as shown in Figure 1, an operation box 4 is attached to the -Y axis end (front end) of the base 2, and an input means 5 such as a keyboard for inputting various data is provided on this operation box 4, and a monitor device 6 that displays images captured by the imaging unit 23 and laser processing conditions of the wafer W is installed on the support base 3.

[0029] (First transport means and second transport means) As shown in Figure 1, a first transport means 30 is provided near the temporary storage section 80 to hold the workpiece W temporarily placed on the rail 81 of the temporary storage section 80 and transport it to the chuck table 10. This first transport means 30 is configured to hold the wafer W at the tip of a first transport arm 31 that is bent in an L-shape in plan view and rotates horizontally around a vertical axis 31a.

[0030] Furthermore, as shown in Figure 1, a second transport means 40 is provided on the side surface 3a of the support base 3 for holding the laser-processed workpiece W and transporting it to the cleaning unit 50. This second transport means 40 includes a second transport arm 41 that is movable in the Y-axis direction (front-to-back direction) along a guide hole 3b formed horizontally along the Y-axis direction (front-to-back direction) on the side surface 3a of the support base 3. Here, the second transport arm 41 is bent in a V-shape when viewed from above, and the workpiece W is held by a transport pad 42 attached to its tip.

[0031] (Washing unit) The cleaning unit 50 performs the function of forming a water-soluble resin protective film F (see Figure 9) on the upper surface of the wafer W before laser processing, and cleaning the wafer W after laser processing with cleaning water to remove the protective film F from the upper surface of the wafer W. As shown in Figure 1, the cleaning unit 50 is located approximately in the center of the base 2, and as shown in Figure 5, it includes a holding table 51 for holding the wafer W before and after laser processing, a resin supply nozzle 52, a cleaning water nozzle 53, and a light source housing 60. Here, the resin supply nozzle 52 is connected to a resin supply source (not shown), and these resin supply nozzles 52 and the resin supply source constitute a resin supply unit. Similarly, the cleaning water nozzle 53 is connected to a cleaning water supply source (not shown), and these cleaning water nozzles 53 and the cleaning water supply source constitute a cleaning water supply unit.

[0032] As shown in Figure 5, the holding table 51, resin supply nozzle 52, and cleaning water nozzle 53 are housed in a drum-shaped water receiving case 54 that opens at the top. Here, the holding table 51 is horizontally mounted on the upper end of a rotating shaft 56 that extends vertically upward from an electric motor 55, which is a rotational drive source located below the water receiving case 54. In addition, the holding surface 51a on the upper surface of the holding table 51 is selectively connected to a suction source (not shown), such as a vacuum pump.

[0033] Furthermore, a circular exhaust port 54a is provided at the top of the side wall of the water receiving case 54, and one end of the piping 67 is connected to this exhaust port 54a. In addition, a cylindrical portion 54A is integrally erected in the center of the bottom wall of the water receiving case 54, through which the rotating shaft 56 passes, and an inverted dish-shaped sealing member 57 attached to the rotating shaft 56 is placed over the outer circumference of this cylindrical portion 54A from above. These cylindrical portion 54A and sealing member 57 perform a sealing function that prevents the cleaning water from leaking out of the water receiving case 54 through a labyrinth effect.

[0034] Furthermore, the resin supply nozzle 52 comprises a vertical shaft portion 52a that rotates around a vertical axis center by an electric motor 58, and an arm portion 52b that extends horizontally from the upper end of the shaft portion 52a, with the tip portion 52c of the arm portion 52b being bent vertically downward and opening downward. Similarly, the washing water nozzle 53 comprises a vertical shaft portion 53a that rotates around a vertical central axis by an electric motor 59, and an arm portion 53b that extends horizontally from the upper end of the shaft portion 53a, with the tip portion 53c of the arm portion 53b being bent vertically downward and opening downward.

[0035] Incidentally, the cleaning unit 50 is provided with a light source housing 60 located above the water receiving case 54 and selectively attached to the upper surface of the water receiving case 54. This light source housing 60 is formed in the shape of a hollow disc having the same outer diameter as the water receiving case 54, and as shown in Figure 5, the light source housing chamber S1 inside it houses a plurality (eight in the illustrated example) of round rod-shaped xenon flash lamps 61 that are long in the direction perpendicular to the plane of the paper in Figure 5 as light sources. Each xenon flash lamp 61 is, for example, a light source that emits pulsed light with a wavelength of 200 nm to 1000 nm, and is equipped with an oscillator (not shown) that emits this pulsed light. In this embodiment, the xenon flash lamps 61 used emit pulsed light with an emission frequency of 3 Hz to 100 Hz, and the energy per pulse of the pulsed light is 10 J to 1000 J. Note that the number of xenon flash lamps 61 is arbitrary as long as they can irradiate the entire holding table 10. In addition to the xenon flash lamp 61, halogen lamps (peak wavelength: 900nm~1600nm) and quartz lamps (peak wavelength: 1500nm~5600nm) can also be used as light sources.

[0036] Here, the bottom wall 60a (see Figure 5) of the light source housing 60 is made of glass such as CaF2 (calcium fluoride) which has high light transmittance, and a circular communication hole 62 that functions as a supply passage is formed in this bottom wall 60a. In addition, an air inlet 63 is formed in the side wall 60b of the light source housing 60, and an air supply source 64 such as an air compressor is connected to this air inlet 63 by piping 65. An electromagnetically operated valve V is provided in the piping 65.

[0037] As shown in Figure 1, the light source housing 60 configured as described above is attached to the tip of a support arm 66 that is movable in the Y-axis direction (front-to-back direction) along a guide hole 3b formed horizontally along the Y-axis direction (front-to-back direction) on the side surface 3a of the support base 3. Therefore, by moving the support arm 66 and the light source housing 60 in the Y-axis direction with a drive source (not shown), the light source housing 60 is selectively attached to the upper surface of the water receiving case 54 as described later.

[0038] [Operation of laser processing equipment] Next, a laser processing method for wafers according to the present invention, which is performed using the laser processing apparatus 1 configured as described above, will be described below.

[0039] In this embodiment, as shown in Figure 4, laser processing of the wafer W is performed through the following steps: 1) holding table heating step, 2) wafer holding step, 3) resin supply step, 4) protective film formation step, 5) laser beam irradiation step, and 6) cleaning step. Each step will be described below.

[0040] 1) Holding table heating step: The holding table heating step is performed prior to the next step, the wafer holding step, and involves preheating the holding table 51 of the cleaning unit 50. In this holding table heating step, as shown in Figure 5, the light source housing 60 is moved in the -Y axis direction and brought into contact with the upper surface of the water receiving case 54. As a result, the upper opening of the water receiving case 54 is covered by the bottom wall 60a of the light source housing 60, thus defining a processing chamber S2 inside the water receiving case 54. The processing chamber S2 houses the holding table 51, resin supply nozzle 52, cleaning water supply nozzle 53, and the like.

[0041] In the above state, power is supplied from an unshown power supply to the multiple xenon flash lamps 61 housed in the light source housing chamber S1 of the light source housing unit 60 to light up these xenon flash lamps 61. As a result, pulsed light emitted from the multiple xenon flash lamps 61 passes through the transparent bottom wall 60a of the light source housing unit 60 and irradiates the upper surface of the holding table 61 in the processing chamber S2, so that the upper surface of the holding table 61 is heated (preheated) to a predetermined temperature (for example, about 70°C).

[0042] 2) Wafer holding step: As described above, in the holding table heating step, once the holding table 51 of the cleaning unit 50 is heated (preheated) to a predetermined temperature, the next wafer holding step is performed. In this wafer holding step, one wafer W is taken out of the cassette 70 by the loading / unloading means 90 shown in Figure 1 and placed on a pair of rails 81 of the temporary storage section 80.

[0043] On the other hand, in the cleaning unit 50, the light source housing 60 moves and retracts from the water receiving case 54, so that the top surface of the water receiving case 54 opens, as shown in Figure 6. From this state, the first transport means 30 shown in Figure 1 holds the wafer W that is placed on the pair of rails 81 of the temporary storage unit 80 and transports it to the cleaning unit 50, where the wafer W is placed on the holding table 51. Then, the holding surface 51a of the holding table 51 is vacuumed by a suction source (not shown), so the wafer W placed on the holding table 51 is held in place by suction to the holding surface 51a of the holding table 51.

[0044] 3) Resin supply step: In the wafer holding step described above, once the wafer W is held by suction on the holding surface 51a of the holding table 51, the next resin supply step is performed. In this resin supply step, the light source housing 60 provided in the cleaning unit 50 moves and is again attached to the upper part of the water receiving case 54 as shown in Figure 7, defining a processing chamber S2 within the water receiving case 54. From this state, the electric motor 58 is started, and the arm portion 52b of the resin supply nozzle 52 housed in the processing chamber S2 rotates around the shaft portion 52a, and the tip portion 52c of the arm portion 52b, which was waiting in the retracted position, moves above the center of the wafer W.

[0045] From the above state, a water-soluble liquid resin f is supplied from a resin supply source (not shown) to the resin supply nozzle 52, and a predetermined amount of liquid resin f is dripped from the tip 52c of the resin supply nozzle 52 toward the center of the wafer W. At this time, the electric motor 55 is started and the rotating shaft 56 and the holding table 51 attached to the upper end of the rotating shaft 56 are rotated together with the wafer W at a predetermined speed.

[0046] Therefore, when a predetermined amount of liquid resin f is dropped from the resin supply nozzle 52 onto the center of the rotating wafer W, the liquid resin f spreads uniformly in a film-like manner radially outward across the upper surface of the wafer W due to the centrifugal force accompanying the rotation of the wafer W. In this case, as described above, in the holding table heating step, the holding table 51 is heated (preheated) to a predetermined temperature (for example, 70°C), so the wafer W held on the holding surface 51a of the holding table 51 and the liquid resin f dropped and spreading on its upper surface are also heated. When the liquid resin f is heated in this way, its viscosity decreases and its fluidity is increased. As a result, the liquid resin f spreads quickly across the upper surface of the wafer W, forming a layer of liquid resin f of uniform thickness over the entire upper surface of the wafer W. For example, polyvinyl alcohol (PVA) is preferably used as the water-soluble liquid resin f.

[0047] 4) Protective film formation step: As described above, in the resin supply step, when an uncured liquid resin f of uniform thickness spreads in a film-like manner on the upper surface of the wafer W, in the next protective film formation step, as shown in Figure 8, pulsed light emitted from a plurality of xenon flash lamps 61 housed in the light source housing 60 passes through the transparent bottom wall 60a of the light source housing 60 and irradiates the film-like liquid resin f on the upper surface of the wafer W, causing the liquid resin f to dry (solidify). As a result, as shown in Figure 9, a protective film F of a desired thickness h (for example, 20 μm) is formed on the upper surface of the wafer W.

[0048] In this protective film formation step, the valve V shown in Figure 8 is opened, and air from the air supply source 64 flows through the piping 65 and into the light source housing chamber S1 through the air inlet 63 that opens into the light source housing section 60. As this air flows through the light source housing chamber S1 in the direction indicated by the arrows in Figure 8, it cools the heat-generating xenon flash lamps 61 and becomes heated air at a high temperature (for example, about 50°C). This heated air then flows into the processing chamber S2 through the communication hole 62. At this time, the holding table 51 and the wafer W held on its upper surface are rotated at a predetermined speed.

[0049] The heated air flowing into the processing chamber S2 flows through the processing chamber S2 inside the water receiving case 54 towards the exhaust port 54a in the direction of the arrow in Figure 8. In the process, the processing chamber S2 is heated to promote the drying of the liquid resin f, and the water vapor generated by the drying of the liquid resin f (evaporation of moisture) is discharged from the exhaust port 54a through the piping 67 into the atmosphere outside the processing chamber S2. As a result, the vapor pressure inside the processing chamber S2 decreases, further promoting the drying of the liquid resin f (evaporation of moisture), and the absorption of pulsed light irradiated from the xenon flash lamp 61 by the water vapor is suppressed. Therefore, the pulsed light is efficiently irradiated onto the liquid resin f, heating it, which also promotes the drying of the liquid resin f.

[0050] As described above, in the protective film formation step, the heated air, which has been heated by cooling the xenon flash lamp 61 in the light source housing chamber S1, flows into the processing chamber S2 through the communication hole 62, and the water vapor generated by the drying of the liquid resin f formed on the surface of the wafer W is discharged outside the processing chamber S2. As a result, the liquid resin f dries and solidifies quickly, and a protective film F is quickly formed on the upper surface of the wafer W in a short amount of time.

[0051] Furthermore, the xenon flash lamp 61 housed in the light source housing chamber S1 of the light source housing unit 60 is effectively cooled by the air flowing into the light source housing chamber S1 from the air supply source 64, thereby suppressing the rise in temperature. As a result, the xenon flash lamp 61 maintains high luminous efficiency and ensures high durability.

[0052] 5) Laser beam irradiation step: In the protective film formation step, as described above, once the protective film F is formed on the upper surface of the wafer W, the light source housing 60 retracts from the water receiving case 54, as shown in Figure 6. As a result, the upper surface of the water receiving case 54 opens, and the wafer W with the protective film F formed on its upper surface is held by the second transport means 40 shown in Figure 1 and transported to the chuck table 10 waiting at the transfer position P2.

[0053] As described above, the wafer W, which has been transported to the chuck table 10, is held in place by suction on the holding surface 10a of the chuck table 10 by a suction source (not shown) (see Figure 6).

[0054] On the other hand, at the processing position P1 shown in Figure 1, once an image is obtained by imaging the surface of the wafer W with the imaging unit 23, the street L to be processed is detected by pattern matching processing based on that image. Once the street L of the wafer W is detected in this way, the position of the laser beam irradiation unit 20 in the Y-axis direction (indexing direction) is determined, and the position of the laser beam irradiation unit 20 in the Y-axis direction is aligned with the position of the street L to be processed on the wafer W by an index feeding means (not shown).

[0055] Then, from the above state, the laser beam irradiation unit 20 is moved to a predetermined height position by a Z-axis moving means (lifting mechanism) not shown, and the chuck table 10 and the wafer W held therein are moved in the -X direction by an X-axis moving means not shown.

[0056] Then, at the processing position P1, the laser beam emitted from the laser head 22 of the laser beam irradiation unit 20 is irradiated along the street L of the wafer W held on the chuck table 10, and grooves 100 shown in Figure 10 are formed on the wafer W along the street L by ablation processing. At this time, since a protective film F is formed on the surface of the wafer W, debris generated during laser processing does not adhere to the surface of the wafer W. Furthermore, as shown in Figure 10, the protective film F is formed to a sufficient thickness to cover up to the top of the bump BP protruding from the wafer W, so even if the wafer W is plasma-etched by exposure of the protective film F to the plasma excited during laser processing, the wafer W is not damaged.

[0057] Then, once the above laser processing of the wafer W has been performed along all streets L in one direction, the chuck table 10 and the wafer W held therein are rotated by 90° by a rotating mechanism (not shown), and laser processing is similarly performed along the other street L perpendicular to the street L in which the grooves 100 have been formed. Once the grooves 100 have been formed along all streets L of the wafer W, the next cleaning step is performed as shown in Figure 11.

[0058] 6) Washing step: In the cleaning step, the wafer W, which has been laser-processed in the laser irradiation step, is transported from the chuck table 10 to the holding table 51 of the cleaning unit 50 by the second transport means 40 shown in Figure 1. The wafer W is then held on the holding table 51 by a suction source (not shown). From this state, the electric motor 55 is activated, and the holding table 51 and the wafer W held therein are rotated at a predetermined speed around a vertical central axis. The electric motor 59 is also activated, and the tip 53c of the arm portion 53b of the cleaning water nozzle 53, which had been retracted to a standby position, rotates around the shaft portion 53a and moves above the center of the wafer W, and cleaning water is sprayed from the tip 53c toward the wafer W. Pure water is preferably used as the cleaning water.

[0059] As described above, when cleaning water is sprayed from the cleaning water nozzle 53 toward the wafer W, the water-soluble protective film F formed on the surface of the wafer W is dissolved by the cleaning water and removed from the surface of the wafer W along with the debris. Finally, by dividing the wafer W along the grid-like grooves 100 formed on its surface, multiple semiconductor chips, each with a device D formed on it, are obtained.

[0060] As is clear from the above explanation, the wafer W processing method according to the present invention, which is carried out using the laser processing apparatus 1 which is a wafer W processing apparatus according to the present invention, has the effect of quickly drying the liquid resin f supplied to the upper surface of the wafer W and efficiently forming a protective film F of sufficient thickness on the upper surface of the wafer W in a short time.

[0061] Incidentally, in the above embodiment, a communication hole 62 is formed in the bottom wall 60a of the light source housing section 60, and a configuration is adopted in which the light source housing chamber S1 and the processing chamber S2 are connected by the communication hole 62 in the protective film formation step. However, as shown in Figure 12, a configuration may also be adopted in which the light source housing chamber S1 and the processing chamber S2 are connected by a duct 67 that constitutes a supply path, and the heated air from the light source housing chamber S1 is discharged outside the light source housing chamber S1 by the duct 67 before being introduced into the processing chamber S2.

[0062] In the embodiments described above, a laser processing apparatus 1 that forms grooves 100 on the surface of a wafer W by irradiation with a laser beam was described as an example of a wafer W processing apparatus. However, the present invention is similarly applicable to wafer W processing apparatuses that perform any other processing on the wafer W using a laser beam.

[0063] Furthermore, in the above embodiments, the holding table heating step was performed before the wafer holding step. However, this holding table heating step is not necessarily essential to the present invention and may be performed only if necessary.

[0064] Furthermore, in the embodiments described above, a wafer W to be processed was described as having a device D with protruding bumps BP, but the present invention can also be applied to wafers in which devices without bumps are formed.

[0065] Furthermore, the present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the technical idea described in the claims, specification, and drawings. [Explanation of Symbols]

[0066] 1: Laser processing equipment (wafer processing device), 2: Base, 3: Support stand, 3a: Side of the support base, 3b: Guide hole in the support base, 4: Operation box, 5: Input means, 6: Monitoring device, 10: Chuck table, 10a: Holding surface, 20: Laser beam irradiation unit, 21: Oscillator, 22: Laser head, 23: imaging unit, 30: first transport means, 31: first transport arm, 31a: axis, 40: Second transport means, 41: Second transport arm, 42: Transport pad, 50: Washing unit, 51: Holding table, 51a: Holding surface, 52: Resin supply nozzle, 52a: Shaft, 52b: Arm, 52c: Tip, 53: Line water purification nozzle, 53a: Shaft, 53b: Arm, 53c: Tip, 54: Water receiving case 54A: Cylindrical part of the water receiving case, 54a: Exhaust port, 55: Electric motor, 56: Rotating shaft, 57: sealing member, 58, 59: electric motor, 60: light source housing, 60a: bottom wall, 60b: Side wall, 61: Xenon flash lamp (light source), 62: Communication hole (supply path), 63: Air inlet, 64: Air supply source (gas supply source), 65: Piping, 66: Support arm, 67: Piping, 68: Duct (supply path), 70: Cassette, 80: Temporary storage area, 81: Rail, 90: Loading / unloading means, 100: Groove, BP: Bump, D: Device, F: Protective film, f: Liquid resin, h: Thickness of protective film, L: Street, P1: Processing location, P2: Transfer location, S1: Light source housing room, S2: Processing room, V: valve, W: wafer

Claims

1. A processing chamber housing a holding table for holding wafers and a resin supply unit for supplying liquid resin to wafers held on the holding table, A light source that irradiates light onto a liquid resin supplied to a wafer from a resin supply unit to dry the liquid resin and form a protective film on the surface of the wafer, A light source housing section that houses the light source, A gas supply unit that supplies gas into the light source housing, A supply path connects the light source housing and the processing chamber, and supplies heated gas that has passed through the light source housing to the processing chamber. An exhaust port for discharging heated gas from the processing chamber to the outside, Equipped with, A wafer processing apparatus characterized by accelerating the drying of the liquid resin by using heated gas supplied to the processing chamber through the supply channel.

2. The wafer has multiple device regions on its surface, demarcated by lines designated for division. A laser beam irradiation unit that irradiates the wafer with a laser beam along the planned division line through the protective film, A cleaning unit for cleaning wafers that have been irradiated with a laser beam by the laser beam irradiation unit, The wafer processing apparatus according to claim 1, further comprising the above.

Images