JP2023119102A - Coating method - Google Patents

Abstract

To remove air bubbles from a liquid resin before being spread after having been coated.SOLUTION: A coating method for coating a surface side of a wafer with a solid resin includes a holding step of holding a rear face side of the wafer positioned on a side opposite to the surface with a holding table, a coating step of coating a liquid resin to the surface side of the wafer or a plate-like object after the holding step, a heating step of heating the liquid resin after the coating step, and a pressing step of pressing at least one of the plate-like object and the wafer and bonding the plate-like object and the wafer through the liquid resin, after the heating step, and bursts air bubbles contained in the liquid resin by the heating step.SELECTED DRAWING: Figure 1

Description

The present invention relates to a coating method for coating the surface side of a wafer with a resin.

When grinding the back side of a wafer on which a plurality of devices are formed on the front side and a plurality of bumps are formed in contact with each device, it is necessary to take care that the unevenness on the front side due to the bumps or the like is transferred to the back side. In order to prevent this and reduce in-plane variations in thickness, it is known to form a resin layer having a thickness sufficient to absorb unevenness on the surface side (see, for example, Patent Document 1).

Specifically, after a liquid UV (ultraviolet) curable resin is supplied to the front surface of the wafer, the liquid resin is cured by UV irradiation. Thereby, the front side of the wafer is covered with a solid resin layer having a substantially flat outer surface.

However, when the surface side of the wafer is covered with the liquid resin, air bubbles are mixed in the liquid resin. When the liquid resin containing air bubbles is cured, bumps, devices, etc. located near the air bubbles may not be properly protected by the resin layer and may be damaged by the pressure, impact, etc. applied to the wafer during grinding. .

Air bubbles are mixed into the liquid resin. When the liquid resin is pushed out onto the front surface of the wafer, the liquid resin is separated into two regions, creating air bubbles. These air bubbles are taken into the liquid resin. A mechanism has been proposed (see, for example, Patent Document 2).

Therefore, in Patent Document 2, the surface side of the wafer is kept in contact with the liquid resin applied on the table in a dome shape, and the wafer is moved to the table while repeatedly moving the wafer toward and away from the table. A method has been proposed in which air bubbles are prevented from being taken into the liquid resin when the liquid resin is spread out by bringing it closer to the table.

JP 2017-50536 A JP 2018-67586 A

However, when the liquid resin is applied onto the table or wafer, the liquid resin may already contain air bubbles. SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and an object of the present invention is to remove air bubbles from a liquid resin after it is applied and before it is spread.

According to one aspect of the present invention, there is provided a coating method for covering the front side of a wafer with a solid resin, comprising: a holding step of holding a back side of the wafer located opposite to the front side with a holding table; After the holding step, a coating step of coating a liquid resin on the surface side of the wafer or a plate-like object; after the coating step, a heating step of heating the liquid resin; a pressing step of pressing at least one of the object and the wafer to bond the plate-like object and the wafer together via the liquid resin, and bursting bubbles contained in the liquid resin by the heating step. A method is provided.

Preferably, in the heating step, the liquid resin is heated by jetting hot air.

According to another aspect of the present invention, there is provided a coating method for covering the front side of a wafer with a solid resin, comprising a holding step of holding the back side of the wafer located on the side opposite to the front side with a holding table; After the holding step, a coating step of coating a liquid resin on the surface side of the wafer or the plate-shaped object; after the coating step, an ultrasonic wave applying step of applying ultrasonic waves to the liquid resin; a pressing step of pressing at least one of the plate-like object and the wafer to bond the plate-like object and the wafer together via the liquid resin after the applying step, wherein A coating method is provided for bursting air bubbles contained in a liquid resin.

Preferably, the liquid resin is a UV curable resin, the plate is a UV-transmissive transparent substrate, and the coating method comprises applying the plate to the UV curable resin after the pressing step. It further comprises a UV irradiation step of irradiating UV through the object.

Also, preferably, the liquid resin is a thermosetting resin, and the coating method further comprises a thermosetting step of heating and curing the thermosetting resin after the pressing step.

In the coating method according to one aspect of the present invention, even if air bubbles are mixed in when the liquid resin is applied, the air bubbles can be removed from the liquid resin by bursting the air bubbles.

1 is a flow diagram of a coating method; FIG. FIG. 13 shows a holding step; FIG. 10 is a diagram showing a coating step; FIG. 10 illustrates a heating step; FIG. 4 is a schematic diagram showing a liquid resin and the like after a heating step; It is a figure which shows a pressing step. It is a figure which shows a UV irradiation step. FIG. 8A is a photograph of the liquid resin before the heating step taken from above, and FIG. 8B is a photograph of the liquid resin after the heating step taken from above. It is a figure which shows the holding|maintenance step which concerns on 2nd Embodiment. It is a figure which shows the application|coating step which concerns on 2nd Embodiment. FIG. 10 is a diagram showing a heating step according to the second embodiment; FIG. 10 is a schematic diagram showing liquid resin and the like after a heating step according to the second embodiment; It is a figure which shows the pressing step which concerns on 2nd Embodiment. It is a figure which shows the UV irradiation step which concerns on 2nd Embodiment. FIG. 10 is a flow diagram of a coating method according to a third embodiment; FIG. 11 illustrates a thermal curing step according to the third embodiment; FIG. 11 is a flow diagram of a coating method according to a fourth embodiment; It is a figure which shows the ultrasonic wave application step which concerns on 4th Embodiment. It is a figure which shows the ultrasonic wave application step which concerns on 5th Embodiment. FIG. 11 is a flowchart of a coating method according to a sixth embodiment;

An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. In this embodiment, in order to cover the surface 11a side of the wafer 11 (see FIG. 2) with a hardened solid resin layer (solid resin) 25 (see FIG. 7), each step is performed in the procedure shown in FIG. do.

FIG. 1 is a flowchart of the coating method according to the first embodiment, in which holding step S10, coating step S20, heating step S30, pressing step S40 and UV irradiation step S50 are executed in this order.

First, the processing device 2 used when covering the surface 11a side with the resin layer 25 will be described with reference to FIGS. 2 to 7. FIG. As shown in FIG. 2, the processing device 2 has a disc-shaped chuck table (holding table) 4 . The chuck table 4 has a metal frame having a larger diameter than the wafer 11 .

A disk-shaped recess (not shown) is formed on the upper surface of the frame, and a disk-shaped porous plate (not shown) made of porous ceramics is fixed to the recess. A plurality of grooves (not shown) are radially formed in the bottom of the recess.

Each groove of the frame is connected to a through hole (not shown) formed in the frame so as to penetrate the center of the frame in the radial direction. A suction source (not shown) such as an ejector is connected to this through hole. Negative pressure generated by the suction source is transmitted to the upper surface of the porous plate through the frame.

The upper surface of the frame and the upper surface of the porous plate are substantially flush with each other, and function as a holding surface 4a that holds the wafer 11 by suction. On the holding surface 4a, the rear surface 11b side of the wafer 11 located on the side opposite to the front surface 11a is held by suction.

The wafer 11 includes a disk-shaped single-crystal substrate 13 having a predetermined diameter (eg, 12 inches (ie, approximately 300 mm)). The single-crystal substrate 13 is made of silicon, for example, but may be made of other materials such as silicon carbide (SiC) and gallium nitride (GaN).

The front surface of single crystal substrate 13 corresponds to front surface 11 a of wafer 11 , and the back surface of single crystal substrate 13 corresponds to back surface 11 b of wafer 11 . A plurality of planned dividing lines (streets) are set in a grid pattern on the surface of the single crystal substrate 13 (not shown).

A device such as an IC (Integrated Circuit) is formed in each of the rectangular areas partitioned by a plurality of streets. Devices are, for example, digital ICs such as logic ICs and memory ICs, and analog ICs.

However, the type of device is not particularly limited. For example, the device may be a light-emitting element such as an LED (Light Emitting Diode), or a MEMS (Micro Electro Mechanical Systems).

One or more bumps 15 made of gold (Au), solder, or the like are electrically connected to each device. The unevenness is formed on the front surface 11a side of the wafer 11 by the bumps 15 and the devices.

A protective film 17 is provided on the side of the surface 11a in such a manner as to closely follow the irregularities on the side of the surface 11a. Protective film 17 is provided, for example, to prevent physical and/or chemical damage to bumps 15 and the device.

The protective film 17 is made of resin and has a thickness of 5 μm or more and 200 μm or less. However, the protective film 17 is not thick enough to absorb the irregularities on the surface 11a side. Therefore, even if the protective film 17 is provided on the surface 11a side, the unevenness cannot be completely eliminated.

The protective film 17 has, for example, a laminate structure of an adhesive layer and a substrate layer, and the adhesive layer side is attached to the surface 11a side. The adhesive layer is made of, for example, acrylic resin or epoxy resin, and the base material layer is made of, for example, polyolefin or polyvinyl chloride.

However, the protective film 17 may have only the substrate layer without the adhesive layer. In this case, the base material layer is attached in close contact with the surface 11a side. The protective film 17 is attached in close contact with the surface 11a by vacuum bonding, thermocompression bonding, pressing, or the like.

The chuck table 4 is configured to be movable along a horizontal direction orthogonal to the Z-axis direction (for example, vertical direction, vertical direction) by an X-axis and Y-axis direction moving mechanism (not shown). When the chuck table 4 is in the loading/unloading area A1, the wafer 11 is loaded into or unloaded from the holding surface 4a.

When the chuck table 4 is in the coating degassing area A2 (see FIG. 3) different from the loading/unloading area A1, the coating heating unit 6 is arranged directly above the holding surface 4a. The application/heating unit 6 has a dispenser (that is, a fixed quantity liquid ejection device) 8 for applying the liquid resin 21 .

The dispenser 8 is, for example, an air pulse system. Dispenser 8 includes syringe 10 containing liquid resin 21 . A controller 12 is connected to the syringe 10 to control the timing of ejection, the amount of ejection, and the like. A needle or nozzle is provided at the lower end of the syringe 10 .

An annular nozzle 14 is arranged on the outer periphery of the lower end of the syringe 10 . The opening 14 a of the annular nozzle 14 is arranged to face downward and is a slit formed over 360 degrees in the circumferential direction of the annular nozzle 14 . However, the annular nozzle 14 may have a plurality of openings 14 a arranged at approximately equal intervals over 360 degrees in the circumferential direction of the annular nozzle 14 .

A hot air supply mechanism 16 including a heater, a motor, a fan, etc. is connected to the annular nozzle 14 . When the hot air supply mechanism 16 is operated, hot air 14b is jetted downward from the opening 14a (see FIG. 4).

The annular nozzle 14 is provided with a position adjusting mechanism (not shown) for adjusting the position in the Z-axis direction. The height position of the annular nozzle 14 is adjusted.

The annular nozzle 14 and the hot air supply mechanism 16 constitute a heating unit 18 that heats the liquid resin 21 with hot air 14b. The heating unit 18 heats the liquid resin 21 to a temperature at which the liquid resin 21 does not harden.

By the way, when the chuck table 4 is in the bonding area A3 different from the loading/unloading area A1 and the coating/degassing area A2 (see FIG. 6), there is no pressure above the chuck table 4 located in the bonding area A3. A unit 20 is arranged.

The pressing unit 20 has an arm 22 movable along the Z-axis direction. For example, a ball screw type Z-axis direction movement mechanism (not shown) is attached to the arm 22, and the Z-axis direction position of the arm 22 is adjusted by the Z-axis direction movement mechanism. A disk-shaped suction part 24 is fixed to the lower end of the arm 22 .

The suction unit 24 has substantially the same structure as the chuck table 4 and includes a frame and a porous plate. Negative pressure can be transmitted to the porous plate from a suction source (not shown), and the bottom surface 24a of the suction portion 24 functions as a holding surface for holding the disk-shaped carrier substrate (plate-like object) 23 by suction.

The diameter of the carrier substrate 23 is, for example, approximately equal to the diameter of the wafer 11 , but may be larger than the diameter of the wafer 11 . Also, the carrier substrate 23 has a predetermined thickness of, for example, 500 μm or more and 1000 μm or less.

The carrier substrate 23 is a transparent substrate having transparency to light in the UV band and visible light band. As the carrier substrate 23, a glass substrate such as non-alkali glass or quartz glass, a transparent resin substrate such as acrylic resin, a single crystal sapphire substrate, or the like is used.

The carrier substrate 23 held by suction on the bottom surface 24a is transferred to the wafer 11 held by suction on the holding surface 4a. After that, the chuck table 4 moves horizontally and is placed in the UV irradiation area A4 (see FIG. 7).

A lamp unit 26 is provided above the chuck table 4 arranged in the UV irradiation area A4. The lamp unit 26 includes a plurality of UV lamps 26a capable of emitting UV. Each UV lamp 26a is a mercury discharge lamp, a metal halide lamp, or the like.

Next, a coating method for coating the surface 11a side with the resin layer 25 using the processing apparatus 2 will be described in more detail. FIG. 2 is a diagram showing the holding step S10. In the holding step S10, the back surface 11b side of the wafer 11 is suction-held by the holding surface 4a of the chuck table 4 arranged in the loading/unloading area A1.

After the holding step S10, the chuck table 4 is moved to the coating and degassing area A2. At this time, the position of the chuck table 4 is adjusted so that the center of the surface 11a of the wafer 11 is positioned substantially directly below the syringe 10 (see FIG. 3).

Then, the controller 12 is operated to discharge a predetermined amount of liquid resin 21 from the syringe 10 . For example, when the thickness of the wafer 11 is reduced to 165 μm by grinding, 15 ml of liquid resin 21 is applied to the front surface 11 a side of the wafer 11 .

FIG. 3 is a diagram showing the application step S20 of applying the liquid resin 21 to the central portion of the wafer 11 on the front surface 11a side. The liquid resin 21 of the first embodiment is a UV curable resin that is cured by reacting with UV.

UV curable resins include, for example, ResiFlat (both registered trademarks) manufactured and sold by Disco Co., Ltd., and Templock and TEMPLOC (both registered trademarks) manufactured and sold by Denka Co., Ltd. may be used.

The applied liquid resin 21 is deposited in a dome shape in the central portion on the side of the surface 11a. The applied liquid resin 21 contains gas such as atmospheric gas such as air as air bubbles 21a due to suckback in the dispenser 8 or the like.

Therefore, in this embodiment, after the application step S20, the heating unit 18 is operated to heat the liquid resin 21, thereby bursting the air bubbles 21a and removing the air bubbles 21a from the liquid resin 21 (heating step S30).

FIG. 4 is a diagram showing the heating step S30. In the heating step S30, the liquid resin 21 is heated at a temperature of 80° C. or higher and 200° C. or lower, more preferably 90° C. or higher and 150° C. or lower, still more preferably 100° C. or higher and 120° C. or lower.

The lower limit of the temperature for heating the liquid resin 21 is determined based on, for example, the rating of the heater in the hot air supply mechanism 16, the degree of expansion of the bubbles 21a, and the like. Also, the upper limit of the temperature when heating the liquid resin 21 is determined, for example, in consideration of suppression of damage to devices formed on the wafer 11 .

In this embodiment, the distance from the annular nozzle 14 to the liquid resin 21 is adjusted to about 50 mm, and hot air 14b of about 100° C. is jetted to the liquid resin 21 at a wind speed of 1.5 m/s for about 5 seconds. Thereby, the liquid resin 21 is heated to approximately 100.degree. Note that the wind speed of the hot air 14b is not limited to 1.5 m/s, and may be a predetermined value of 1.0 m/s or more and 2.0 m/s or less.

The heated bubble 21a expands and eventually reaches the gas-liquid interface between the liquid resin 21 and the ambient gas, and finally bursts and disappears. In particular, in this embodiment, the hot air 14b is uniformly jetted downward from the ring-shaped opening 14a. The warm air 14b can apply impact, vibration, and the like to the liquid resin 21 .

On the other hand, the supply of heat to the liquid resin 21 via electromagnetic waves (that is, thermal radiation, thermal radiation), or the heat conduction from the heater arranged on the chuck table 4 through the wafer 11, the warm air 14b It is difficult to apply such impact, vibration, etc. to the liquid resin 21 .

By using the hot air 14b, in addition to heat, impact, vibration, etc. can be applied to the liquid resin 21, and the bubbles 21a can be moved to the gas-liquid interface more efficiently than heat radiation and heat conduction, and burst. be able to. FIG. 5 is a schematic diagram showing the liquid resin 21 and the like after the heating step S30.

After the heating step S30, as shown in FIG. 6, the chuck table 4 is moved to the bonding area A3 so that the center of the front surface 11a of the wafer 11 and the center of the one surface 23a of the carrier substrate 23 are substantially aligned. Then, the arm 22 is moved downward while the one surface 23a of the carrier substrate 23 whose other surface 23b is sucked and held by the suction unit 24 faces downward.

In this embodiment, the carrier substrate 23 is pressed against the wafer 11 by stopping the chuck table 4 in the Z-axis direction and lowering the suction unit 24 (pressing step S40). FIG. 6 is a diagram showing the pressing step S40.

In the pressing step S40, the liquid resin 21 is pressed and spread over the entire surface 11a side. The pushing amount of the carrier substrate 23 in the Z-axis direction is adjusted so that the liquid resin 21 has a predetermined thickness 21b. In this manner, the wafer 11 and carrier substrate 23 are bonded together with the protective film 17 and the liquid resin 21 interposed therebetween.

If the chuck table 4 is provided with an elevating mechanism (not shown), the wafer 11 may be pressed against the carrier substrate 23 by raising the chuck table 4 with the suction unit 24 stationary. .

Alternatively, the wafer 11 and the carrier substrate 23 may be pressed against each other by lowering the suction unit 24 and raising the chuck table 4 . That is, at least one of the carrier substrate 23 and the wafer 11 may be pressed.

After the pressing step S40, as shown in FIG. 7, the chuck table 4 is moved to the UV irradiation area A4 so that the carrier substrate 23 and the like face the lamp unit . Then, the liquid resin 21 is irradiated with UV through the carrier substrate 23 (UV irradiation step S50).

FIG. 7 is a diagram showing the UV irradiation step S50. In the UV irradiation step S50, for example, the liquid resin 21 is irradiated with UV at an illuminance of 50 mW/cm ² for 12 seconds. As a result, the liquid resin 21 is cured to form a solid resin layer 25 .

In this embodiment, even if air bubbles 21a are mixed in when the liquid resin 21 is applied, the air bubbles 21a can be removed by bursting the air bubbles 21a in the heating step S30. Therefore, compared to the case where the heating step S30 is not performed, it is possible to reduce the possibility of damaging the bumps 15, devices, etc. during the grinding of the back surface 11b side.

Next, with reference to FIGS. 8(A) and 8(B), an experimental example of removing air bubbles 21a by jetting hot air 14b to liquid resin 21 will be described. 8A is a photograph of the liquid resin 21 taken from above before the heating step S30, and FIG. 8B is a photograph of the liquid resin 21 taken from above after the heating step S30.

In this experimental example, the dispenser 8 was used to apply 15 ml of the liquid resin 21 onto the protective film 17 provided on the front surface 11a side of the wafer 11 . The liquid resin 21 after application contained a large number of air bubbles 21a as shown in FIG. 8(A).

The annular nozzle 14 was arranged at a distance of about 50 mm to the liquid resin 21 containing the air bubbles 21a, and hot air 14b of about 100° C. was jetted for about 5 seconds. As a result, as shown in FIG. 8B, the bubbles 21a could be removed.

(Second Embodiment) Next, a second embodiment will be described with reference to FIGS. 9 to 14. FIG. Also in the second embodiment, each step is performed according to the flow chart shown in FIG. However, the second embodiment differs from the first embodiment in that the wafer 11 and the carrier substrate 23 are arranged upside down.

In the second embodiment, first, as shown in FIG. 9, the back surface 11b side of the wafer 11 is sucked and held by the bottom surface (holding surface) 24a of the suction unit (holding table) 24 arranged in the bonding area A3. (Holding step S10). FIG. 9 is a diagram showing the holding step S10 according to the second embodiment.

After the holding step S10, as shown in FIG. 10, the other surface 23b side of the carrier substrate 23 is held by the transparent table 28 arranged in the coating and degassing area A2. In the second embodiment, instead of the chuck table 4, a transparent table 28 is provided.

Like the chuck table 4, the transparent table 28 is configured to be horizontally movable by an X-axis and Y-axis movement mechanism (not shown). A plurality of projections (not shown) are provided on the upper surface 28a of the transparent table 28 to prevent the carrier substrate 23 from being displaced.

The position of the carrier substrate 23 within the upper surface 28a is fixed by the plurality of projections coming into contact with the outer peripheral edge of the carrier substrate 23 . In place of the plurality of protrusions, suction and holding by negative pressure, a clamp that clamps the outer peripheral portion of the carrier substrate 23, or the like may be employed.

The transparent table 28, like the carrier substrate 23, includes a transparent substrate that is transmissive to light in the UV band and visible light band. A liquid resin 21 is applied to one surface 23a of the carrier substrate 23 fixed to the upper surface 28a (application step S20).

FIG. 10 is a diagram showing the coating step S20 according to the second embodiment. The application amount of the liquid resin 21 is the same as in the first embodiment. After the application step S20, the liquid resin 21 is heated by jetting hot air 14b from the annular nozzle 14 (heating step S30), as in the first embodiment.

FIG. 11 is a diagram showing the heating step S30 according to the second embodiment. As described above, in the heating step S30, the bubbles 21a can be removed by bursting. FIG. 12 is a schematic diagram showing the liquid resin 21 and the like after the heating step S30 according to the second embodiment.

After the heating step S30, the transparent table 28 is moved to the bonding area A3. Then, the wafer 11 is pressed against the carrier substrate 23 by lowering the suction part 24 (pressing step S40). FIG. 13 is a diagram showing the pressing step S40 according to the second embodiment.

If the transparent table 28 is provided with an elevating mechanism (not shown), the carrier substrate 23 may be pressed against the wafer 11 by raising the transparent table 28 with the suction unit 24 stationary. .

Alternatively, the wafer 11 and the carrier substrate 23 may be pressed against each other by lowering the suction unit 24 and raising the transparent table 28 . That is, at least one of the wafer 11 and the carrier substrate 23 may be pressed.

After the pressing step S40, the transparent table 28 is moved to the UV irradiation area A4, and the liquid resin 21 is irradiated with UV from the lamp unit 26 through the transparent table 28 and the carrier substrate 23 in the same manner as in the first embodiment. (UV irradiation step S50).

The liquid resin 21 is cured into a solid resin layer 25 by the UV irradiation step S50. FIG. 14 is a diagram showing the UV irradiation step S50 according to the second embodiment. Also in the second embodiment, the bubbles 21a can be removed by bursting the bubbles 21a in the heating step S30.

(Third Embodiment) Next, a third embodiment will be described with reference to FIGS. 15 and 16. FIG. FIG. 15 is a flow diagram of a coating method according to the third embodiment. The third embodiment differs from the first and second embodiments in that a thermosetting resin is used as the liquid resin 21 instead of the UV curable resin.

Therefore, the third embodiment will be described with reference to FIGS. 2 to 6 of the first embodiment. After performing the holding step S10 (see FIG. 2), a liquid resin (thermosetting resin) 21 is applied to the front surface 11a side of the wafer 11 in the coating step S20 (see FIG. 3).

In the subsequent heating step S30 (see FIG. 4), the liquid resin (thermosetting resin) 21 is heated at a predetermined temperature at which the liquid resin (thermosetting resin) 21 does not harden. The thermosetting resin contains, for example, an epoxy resin and a curing agent, and is cured at a predetermined temperature of 150° C. or higher (eg, 200° C.).

Therefore, in the heating step S30 of the second embodiment, the temperature is set to 80° C. or more and less than 150° C., more preferably 90° C. or more and 130° C. or less, and still more preferably 100° C. or more and 110° C. or less so that the liquid resin 21 is not cured by heat. The liquid resin 21 is heated at a temperature of .

The lower limit of the temperature when heating the liquid resin 21 is determined in the same manner as in the first embodiment. Also, the upper limit of the temperature when heating the liquid resin 21 is determined in consideration of preventing the thermosetting resin from hardening, in addition to suppressing damage to the device.

Also in the heating step S30 of the third embodiment, for example, after adjusting the distance from the annular nozzle 14 to the liquid resin 21 to about 50 mm, hot air 14b of about 100° C. is jetted to the liquid resin 21 for about 5 seconds. , the liquid resin 21 is heated to about 100.degree. As a result, the bubble 21a bursts and is removed (see FIGS. 4 and 5).

In the subsequent pressing step S40 (see FIG. 6), the carrier substrate 23 is pressed against the wafer 11 by keeping the chuck table 4 still in the Z-axis direction and lowering the suction unit 24 . At least one of the carrier substrate 23 and the wafer 11 may be pressed.

By the way, in the third embodiment, the liquid resin 21 is cured not by UV but by heat, so the carrier substrate 23 may have substantially no transmittance to light such as UV. For example, the carrier substrate 23 is made of a material having a coefficient of linear thermal expansion substantially equal to that of the wafer 11 .

Specifically, when the wafer 11 has a single crystal silicon substrate, a substrate made of alumina (Al ₂ O ₃ ), aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ), silicon carbide (SiC) or the like is used. A carrier substrate 23 is used.

By making the coefficients of linear thermal expansion of the wafer 11 and the carrier substrate 23 substantially equal, the amount of warpage that occurs in the laminate including the carrier substrate 23, the wafer 11, etc. due to the heat applied when curing the liquid resin 21 can be reduced.

After the pressing step S40, the liquid resin 21 (that is, thermosetting resin) is heated and cured (thermosetting step S55). In the heat curing step S55, the liquid resin 21 is cured by heating at a predetermined temperature of 150° C. or higher.

FIG. 16 is a diagram showing the thermal curing step S55 according to the third embodiment. In the thermosetting step S55, first, the chuck table 4 is moved to the thermosetting area A5 different from the carrying-in/carrying-out area A1, the coating/degassing area A2, and the bonding area A3.

A disk-shaped heater unit 30 is arranged above the chuck table 4 arranged in the thermosetting area A5. Like the pressing unit 20, the heater unit 30 is provided with a ball screw type Z-axis movement mechanism (not shown).

The heater unit 30 includes a plurality of ring-shaped resistance heating elements 32 arranged concentrically. Each resistance heating element 32 is covered with an insulator 34 and constitutes a disk-shaped heating portion.

The heater unit 30 includes a disk-shaped frame 36 made of metal. A disk-shaped concave portion is formed in the bottom portion of the frame 36, and the heat generating portion described above is fixed to this concave portion. Note that the heater unit 30 may have a temperature measurement mechanism, a cooling mechanism, and the like.

By heating the heat generating portion to, for example, 200° C. while the lower surface of the heater unit 30 is in contact with the carrier substrate 23, the heat 32a is transferred to the liquid resin 21 through the carrier substrate 23, and the liquid resin 21 is also heated to 200° C. be hardened.

In this embodiment, the heat 32 a is transferred to the liquid resin 21 through the carrier substrate 23 . etc. can be reduced.

By the way, also in the third embodiment, the liquid resin 21 (that is, the thermosetting resin) may be applied to the one surface 23a of the carrier substrate 23 as in the second embodiment. However, in this case, since UV is not used, the chuck table 4 is used instead of the transparent table 28 to hold the carrier substrate 23 by suction on the holding surface 4a.

(Fourth Embodiment) Next, a fourth embodiment will be described with reference to FIGS. 17 and 18. FIG. FIG. 17 is a flow diagram of a coating method according to the fourth embodiment. The fourth embodiment differs from the above-described embodiments in that ultrasonic waves are applied to the liquid resin 21 instead of the hot air 14b after the application step S20.

Since the holding step S10 and the applying step S20 are the same as those in the first embodiment, the description thereof is omitted. In the ultrasonic wave applying step S35, as shown in FIG. 18, the ultrasonic wave applying unit 40 is used. The ultrasonic wave application unit 40 is arranged, for example, at a position that does not interfere with the dispenser 8 in the application degassing area A2.

The ultrasonic wave applying unit 40 is configured to be movable along the Z-axis direction by a ball screw type Z-axis direction moving mechanism (not shown). The ultrasonic applying unit 40 has an ultrasonic transducer (not shown) that converts electric power into ultrasonic vibrations. The ultrasonic transducer contains, for example, lead zirconate titanate.

A horn 42 that functions as a resonator is attached to the ultrasonic transducer. A nozzle 46 is provided near the horn 42 . A nozzle 46 supplies a liquid 44 such as pure water that functions as an acoustic matching layer between the liquid resin 21 and the horn 42 .

FIG. 18 is a diagram showing the ultrasonic wave applying step S35 according to the fourth embodiment. In the ultrasonic wave application step S35, the liquid resin 21 is covered with the liquid 44 by supplying the liquid 44 onto the liquid resin 21 at a predetermined flow rate.

Then, an ultrasonic wave having a predetermined frequency of 20 kHz or more is applied to the liquid resin 21 from the horn 42 via the liquid 44 . As a result, the air bubbles 21a vibrate and the adjacent air bubbles 21a are connected to each other to increase the volume.

The bubble 21a whose volume has increased eventually reaches the interface between the liquid resin 21 and the liquid 44 and bursts. Then, the gas in the bubble 21a is removed by the flow of the liquid 44. FIG.

Since the pressing step S40 and the UV irradiation step S50 subsequent to the ultrasonic wave application step S35 are the same as those in the first embodiment, description thereof will be omitted. Note that the ultrasonic wave applying step S35 may be applied to the second embodiment (see FIG. 19).

(Fifth Embodiment) FIG. 19 is a diagram showing an ultrasonic wave application step S35 according to a fifth embodiment. In the fifth embodiment as well, ultrasonic waves are applied from the horn 42 to the liquid resin 21 via the liquid 44 to burst and remove the air bubbles 21 a contained in the liquid resin 21 .

(Sixth Embodiment) The ultrasonic wave application step S35 may be applied to the third embodiment (see FIGS. 15 and 16) using the liquid resin 21 (thermosetting resin) (see FIG. 20). FIG. 20 is a flow diagram of a coating method according to the sixth embodiment.

Also in the sixth embodiment, even if bubbles 21a are mixed in when the liquid resin 21 is applied, the bubbles 21a can be removed by bursting the bubbles 21a in the ultrasonic wave applying step S35. Similarly, when the liquid resin 21 (that is, thermosetting resin) is applied to the one surface 23a of the carrier substrate 23, the ultrasonic wave applying step S35 may be applied.

In addition, the structures, methods, and the like according to the above-described embodiments can be modified as appropriate without departing from the scope of the present invention. In the pressing step S40, the surface 11a side is maintained in contact with the liquid resin 21, and the carrier substrate 23 and the wafer 11 are moved relatively close to each other, and the liquid resin 21 is made to have a predetermined thickness while repeating a plurality of times. They may be brought closer together until they reach height 21b.

2: Processing device, 4: Chuck table (holding table), 4a: Holding surface 6: Application heating unit, 8: Dispenser, 10: Syringe, 12: Controller 11: Wafer, 11a: Front surface, 11b: Back surface 13: Single crystal Substrate 15: Bump 17: Protective film 14: Annular nozzle 14a: Opening 14b: Hot air 16: Hot air supply mechanism 18: Heating unit 20: Pressing unit 22: Arm 24: Suction unit (holding table) , 24a: bottom surface (holding surface)
21: Liquid resin, 21a: Bubbles, 21b: Thickness 23: Carrier substrate (plate-like object), 23a: One side, 23b: Other side 25: Resin layer (solid resin)
26: lamp unit, 26a: UV lamp 28: transparent table, 28a: upper surface 30: heater unit, 32: resistance heating element, 32a: heat, 34: insulator, 36: frame 40: ultrasonic wave application unit, 42: Horn, 44: liquid, 46: nozzle A1: loading/unloading area, A2: coating deaeration area, A3: bonding area, A4: UV irradiation area A5: thermosetting area S10: holding step, S20: coating step S30: heating Step S35: Ultrasonic wave application step S40: Pressing step S50: UV irradiation step S55: Thermal curing step

Claims (5)

A coating method for covering the surface side of a wafer with a solid resin,
a holding step of holding a back side of the wafer located on the side opposite to the front side with a holding table;
After the holding step, a coating step of coating a liquid resin on the surface side of the wafer or on the plate;
After the coating step, a heating step of heating the liquid resin;
a pressing step of, after the heating step, pressing at least one of the plate-like object and the wafer to bond the plate-like object and the wafer together via the liquid resin;
with
A coating method, wherein the heating step bursts air bubbles contained in the liquid resin. 2. The coating method according to claim 1, wherein in the heating step, the liquid resin is heated by jetting hot air. A coating method for covering the surface side of a wafer with a solid resin,
a holding step of holding a back side of the wafer located on the side opposite to the front side with a holding table;
After the holding step, a coating step of coating a liquid resin on the surface side of the wafer or on the plate;
After the application step, an ultrasonic wave applying step of applying ultrasonic waves to the liquid resin;
a pressing step of pressing at least one of the plate-like object and the wafer to bond the plate-like object and the wafer together via the liquid resin after the ultrasonic wave applying step;
with
A coating method, wherein bubbles contained in the liquid resin are burst by the ultrasonic wave applying step. The liquid resin is a UV curable resin,
The plate-shaped object is a transparent substrate having transparency to UV,
4. The coating method according to any one of claims 1 to 3, further comprising a UV irradiation step of irradiating the UV curable resin with UV through the plate after the pressing step. The liquid resin is a thermosetting resin,
4. The coating method according to any one of claims 1 to 3, further comprising a thermosetting step of heating and curing the thermosetting resin after the pressing step.

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