Liquid resin coating device

Abstract

The present invention provides a liquid resin coating apparatus capable of coating the upper surface of a wafer with a protective film of a desired thickness. [Solution] The liquid resin coating apparatus 2 includes a table means 4 equipped with a spinner table 14 that can hold and rotate a wafer 56, a liquid resin nozzle 6 that discharges liquid resin onto the upper surface 56a of the wafer 56 held on the spinner table 14, a liquid resin containment means 8 that contains the liquid resin, a communication means 10 that connects the liquid resin nozzle 6 and the liquid resin containment means 8, and a temperature adjustment means 12. The temperature adjustment means 12 adjusts the temperature to a low temperature at which the viscosity of the liquid resin supplied to the wafer 58 held on the spinner table 14 becomes higher than a predetermined value.

Description

Technical Field

[0001] The present invention relates to a liquid resin coating device for coating a liquid resin on the upper surface of a wafer.

Background Art

[0002] A wafer on which a plurality of devices such as ICs and LSIs are partitioned by a dicing line and formed on the surface is ground on the back surface by a grinding device to form a predetermined thickness, and then divided into individual device chips by a dicing device, a laser processing device, etc. Each of the divided device chips is used in electric devices such as mobile phones and personal computers.

[0003] Further, when ablation processing is performed on the dicing line by a laser processing device, debris scatters and adheres to the surface of the device, leading to a deterioration in quality. Therefore, the applicant has proposed a liquid resin coating device for previously coating a protective film of a water-soluble resin on the surface of a wafer (see, for example, Patent Document 1). This liquid resin coating device is generally composed of a spinner table that holds and rotates a wafer, a liquid resin nozzle that discharges liquid resin onto the upper surface of the wafer held by the spinner table, a liquid resin storage means that stores the liquid resin, and a communication means that communicates the liquid resin nozzle and the liquid resin storage means, and can coat a protective film on the upper surface of the wafer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since the viscosity of the liquid resin is formulated to be low so that the liquid resin can be smoothly delivered from the liquid resin containment means to the liquid resin nozzle, the protective film coated on the upper surface of the wafer becomes relatively thin. Consequently, there is a problem in that it is difficult to coat the upper surface of the wafer with a protective film of the desired thickness.

[0006] The object of the present invention is to provide a liquid resin coating apparatus that can coat the upper surface of a wafer with a protective film of a desired thickness. [Means for solving the problem]

[0007] According to the present invention, the following liquid resin coating apparatus is provided that solves the above problems. That is, A liquid resin coating apparatus for coating the upper surface of a wafer with liquid resin, The system includes a table means equipped with a spinner table that can hold and rotate a wafer, a liquid resin nozzle for dispensing liquid resin onto the upper surface of the wafer held on the spinner table, a liquid resin containment means containing the liquid resin, a communication means connecting the liquid resin nozzle and the liquid resin containment means, and a temperature control means. The provided liquid resin coating apparatus includes a temperature adjustment means that adjusts the temperature to a low temperature at which the viscosity of the liquid resin supplied to the wafer held on the spinner table becomes higher than a predetermined value.

[0008] Preferably, the table means comprises a chamber surrounding the spinner table, and the temperature control means adjusts the atmosphere inside the chamber to the low temperature.

[0009] Preferably, the temperature adjustment means adjusts the temperature of the liquid resin in the liquid resin containment means and the communication means to a high temperature at which the viscosity of the liquid resin falls below a predetermined value, and adjusts the temperature of the liquid resin discharged from the liquid resin nozzle to the low temperature.

[0010] The liquid resin is a water-soluble resin PVA, and the low temperature at which the viscosity of the liquid resin becomes higher than the predetermined value is preferably 7°C or lower, and the high temperature at which the viscosity of the liquid resin becomes lower than the predetermined value is preferably 25°C or higher.

[0011] On the upper surface of the wafer, multiple device regions may be formed, demarcated by lines indicating planned divisions.

[0012] The temperature adjustment means is convenient for adjusting the thickness of the protective film covering the wafer by adjusting the low temperature. [Effects of the Invention]

[0013] The liquid resin coating apparatus of the present invention is A liquid resin coating apparatus for coating the upper surface of a wafer with a liquid resin, The system includes a table means equipped with a spinner table that can hold and rotate a wafer, a liquid resin nozzle for dispensing liquid resin onto the upper surface of the wafer held on the spinner table, a liquid resin containment means containing the liquid resin, a communication means connecting the liquid resin nozzle and the liquid resin containment means, and a temperature control means. The temperature adjustment means adjusts the temperature to a low temperature at which the viscosity of the liquid resin supplied to the wafer held on the spinner table becomes higher than a predetermined value, thereby enabling the coating of a protective film of the desired thickness on the upper surface of the wafer. [Brief explanation of the drawing]

[0014] [Figure 1] A perspective view of the liquid resin coating apparatus according to the present invention. [Figure 2] A schematic cross-sectional view of the liquid resin coating apparatus shown in Figure 1. [Figure 3] Schematic diagram of a liquid resin nozzle shown in Figure 1. [Figure 4] A perspective view showing the wafer's upper surface coated with liquid resin. [Figure 5] A schematic cross-sectional view showing the wafer's upper surface coated with liquid resin. [Figure 6] A graph showing the relationship between the viscosity of a liquid resin and its temperature.

Embodiment for Carrying out the Invention

[0015] Hereinafter, a preferred embodiment of the liquid resin coating apparatus according to the present invention will be described with reference to the drawings.

[0016] (Liquid resin coating apparatus 2) As shown in FIG. 1, the liquid resin coating apparatus 2 of the present embodiment includes table means 4 having a spinner table capable of holding and rotating a wafer, a liquid resin nozzle 6 for discharging liquid resin onto the upper surface of the wafer held by the spinner table, liquid resin storage means 8 for storing the liquid resin, communication means 10 for communicating the liquid resin nozzle 6 and the liquid resin storage means 8, and temperature adjustment means 12.

[0017] (Table means 4 of the liquid resin coating apparatus 2) The table means 4 includes a spinner table 14 capable of holding and rotating a wafer, a motor 16 for rotating the spinner table 14, lifting means 18 for lifting and lowering the spinner table 14, and a chamber 20 surrounding the spinner table 14.

[0018] (Spinner table 14 of the table means 4) The spinner table 14 has a disk-shaped adsorption chuck 22 formed of a porous member such as porous ceramics, a frame body 24 covering the side surface and the lower surface of the adsorption chuck 22, and a cylindrical cover member 26 disposed below the frame body 24. The adsorption chuck 22 is connected to a suction means (not shown). In the spinner table 14, a suction force is generated on the upper surface of the adsorption chuck 22 by the suction means, and the wafer placed on the upper surface of the adsorption chuck 22 is suction-held.

[0019] (Motor 16 of the table means 4) The output shaft 16a of the motor 16 extends in the vertical direction and is connected to the lower surface of the central portion of the frame body 24 of the spinner table 14. The motor 16 rotates the spinner table 14 about the vertical axis.

[0020] (Lifting mechanism 18 of table mechanism 4) The lifting mechanism 18 may consist of a plurality of actuators, such as air cylinders, connected to the outer circumferential surface of the motor 16. The lifting mechanism 18 raises and lowers the spinner table 14 between a raised position where wafers are attached and detached (positions shown in Figures 1 and 2) and a lowered position where liquid resin is applied to the wafers (positions shown in Figures 4 and 5).

[0021] (Chamber 20 of Table Means 4) As shown in Figure 1, the chamber 20 has an annular bottom plate 28, an inner circumferential wall 30 extending upward from the inner circumferential edge of the bottom plate 28, an outer circumferential wall 32 extending upward from the outer circumferential edge of the bottom plate 28, and a plurality of legs 34 extending downward from the lower surface of the bottom plate 28. The bottom plate 28 has a central opening 35 through which the output shaft 16a of the motor 16 passes, and an outlet 36 for discharging liquid resin and cleaning water from the chamber 20. A discharge hose 38 is connected to the outlet 36. The diameter of the inner circumferential wall 30 is smaller than the diameter of the cover member 26 of the spinner table 14. As shown in Figure 5, when the spinner table 14 is positioned in the lowered position, the inner circumferential wall 30 loosely fits inside the cover member 26, preventing liquid resin and cleaning water from leaking out of the chamber 20 through the central opening 35. Furthermore, a disc-shaped cover 40, as shown in Figure 1, is detachably attached to the upper end of the outer peripheral wall 32.

[0022] (Liquid resin nozzle 6 of liquid resin coating device 2) The liquid resin nozzle 6 is located inside the chamber 20 of the table means 4, adjacent to the spinner table 14. As shown in Figure 2, a swivel motor 42 is connected to the liquid resin nozzle 6. The liquid resin nozzle 6 is swiveled by the swivel motor 42, positioning it between a standby position (shown in Figure 1) where the nozzle 6a is spaced away from directly above the spinner table 14, and an injection position (shown in Figures 4 and 5) where the nozzle 6a is located above the center of the spinner table 14.

[0023] (Liquid resin containing means 8 of the liquid resin coating device 2) The liquid resin containment means 8 may be a sealed tank made of metal or synthetic resin. A water-soluble liquid resin, such as polyvinyl alcohol (PVA), is contained inside the liquid resin containment means 8. Preferably, an insulating material (not shown) is provided on the outer surface of the liquid resin containment means 8. This suppresses temperature changes of the liquid resin inside the liquid resin containment means 8.

[0024] (Communication means 10 of the liquid resin coating device 2) As shown in Figure 1, the communication means 10 includes a suitable conduit member 44 such as a hose or pipe, and a pump 46 that sucks up the liquid resin in the liquid resin containment means 8 and sends it to the liquid resin nozzle 6. It is preferable that an insulating material (not shown) is provided on the outer surface of the conduit member 44. This suppresses temperature changes of the liquid resin as it passes through the conduit member 44.

[0025] (Temperature adjustment means 12 of the liquid resin coating device 2) The temperature adjustment means 12 adjusts the temperature of the liquid resin supplied to the wafer held on the spinner table 14 to a low temperature (for example, 7°C or lower) such that the viscosity of the liquid resin becomes higher than a predetermined value. Therefore, even if the liquid resin is formulated so that its viscosity at room temperature (for example, 25°C) is lower than a predetermined value, the temperature of the liquid resin is adjusted to the low temperature so that the viscosity supplied to the wafer becomes higher than the predetermined value, thus eliminating the problem of the protective film covering the upper surface of the wafer becoming relatively thin. The predetermined value can be set to any value depending on the properties of the liquid resin.

[0026] The temperature adjustment means 12 adjusts the atmosphere inside the chamber 20 to the low temperature, for example. In this case, the temperature adjustment means 12 sends cold air into the chamber 20 from a known cold air mechanism (not shown) to adjust the atmosphere inside the chamber 20 to the low temperature. As a result, the temperature of the liquid resin is also adjusted to the low temperature. Alternatively, as shown in Figure 3, the temperature adjustment means 12 may have a Peltier element 12a mounted near the injection port 6a of the liquid resin nozzle 6, and the Peltier element 12a cools the liquid resin discharged from the liquid resin nozzle 6 to adjust the temperature of the liquid resin to the low temperature.

[0027] Furthermore, the temperature adjustment means 12 adjusts the temperature of the liquid resin in the liquid resin containment means 8 and the communication means 10 to a high temperature (for example, 25°C or higher) where the viscosity of the liquid resin is lower than the predetermined value, thereby reducing resistance within the tube and facilitating the movement of the liquid resin. Preferably, the temperature adjustment means 12 adjusts the temperature of the liquid resin discharged from the liquid resin nozzle 6 to the low temperature. This ensures that the liquid resin is smoothly delivered from the liquid resin containment means 8 to the liquid resin nozzle 6 via the communication means 10, and also resolves the problem of the protective film covering the upper surface of the wafer becoming relatively thin.

[0028] The temperature adjustment means 12 has, for example, a known heat exchange mechanism (not shown), and the heat exchange mechanism can adjust the temperature of the liquid resin in the liquid resin containment means 8 and the communication means 10 to a high temperature (for example, 25°C or higher) such that the viscosity of the liquid resin is lower than the predetermined viscosity. The heat exchange mechanism may include a compressor for compressing the refrigerant, a condenser for condensing the refrigerant compressed by the compressor, and an evaporator for vaporizing the refrigerant condensed by the condenser.

[0029] As shown in Figures 1 and 2, the liquid resin coating apparatus 2 includes a cleaning water nozzle 48 (see Figures 1 and 2) for spraying cleaning water onto a laser-processed wafer with a protective film held on a spinner table 14 to remove the protective film and debris from the wafer, a swivel motor 50 (see Figure 2) for swirling the cleaning water nozzle 48, an air nozzle 52 (see Figure 1) for spraying air onto the cleaned wafer held on the spinner table 14 to dry the wafer, and a swivel motor (not shown) for swirling the air nozzle 52.

[0030] (Waha 54) Figure 1 also shows a disc-shaped wafer 54 coated with liquid resin by the liquid resin coating apparatus 2 described above. The wafer 54 can be formed from a suitable semiconductor material such as silicon. On the surface 54a of the wafer 54, a device region is formed in which multiple devices 56 such as ICs and LSIs are demarcated by grid-like division lines 58. The back surface 54b of the wafer 54 is attached to a tape 62 whose periphery is fixed to an annular frame 60, and the wafer 54 is supported by the annular frame 60 via the tape 62.

[0031] (Method of coating with liquid resin) Next, a method for coating the upper surface of the wafer 54 with liquid resin using the liquid resin coating apparatus 2 described above will be explained.

[0032] (holding process) In this embodiment, first, a holding step is performed in which the wafer 54 is held on the spinner table 14 of the liquid resin coating apparatus 2. In the holding step, the wafer 54 is placed on the spinner table 14 with its surface 54a facing upwards. At this time, the rotation center of the spinner table 14 is aligned with the center of the wafer 54. Then, a suction force is generated on the upper surface of the suction chuck 22 of the spinner table 14 to hold the back side 54b of the wafer 54 by suction. During the holding step, the spinner table 14 is positioned in the raised position (position shown in Figure 1). In addition, the liquid resin nozzle 6, the washing water nozzle 48, and the air nozzle 52 are positioned in a standby position (position shown in Figure 1) spaced away from directly above the spinner table 14.

[0033] (Coating process) After the holding process is performed, a coating process is carried out in which liquid resin is supplied to the surface 54a (top surface) of the wafer 54 while the spinner table 14 is rotated, thereby coating the surface 54a of the wafer 54 with liquid resin. In the coating process, first, the spinner table 14 is positioned in a lowered position by the lifting means 18. Next, as shown in Figures 4 and 5, a lid 40 is placed over the upper end of the outer peripheral wall 32 of the chamber 20. Next, the liquid resin nozzle 6 is rotated by the swivel motor 42, and the nozzle 6a of the liquid resin nozzle 6 is positioned at the injection position (above the center of the spinner table 14). Next, the spinner table 14 is rotated at a predetermined rotational speed (for example, 300 rpm) in the direction indicated by arrow R1 in Figure 5. Then, liquid resin is supplied from the nozzle 6a of the liquid resin nozzle 6 to the surface 54a of the wafer 54. As a result, the liquid resin spreads uniformly over the surface 54a of the wafer 54 due to centrifugal force. Then, a protective film is created by solidifying the liquid resin.

[0034] In this embodiment, it is important to adjust the temperature of the liquid resin supplied to the wafer 54 held on the spinner table 14 to a low temperature (for example, 7°C or lower) using the temperature adjustment means 12 so that the viscosity of the liquid resin is higher than a predetermined value. This allows a protective film of the desired thickness to be coated on the surface 54a (top surface) of the wafer 54.

[0035] Furthermore, the temperature adjustment means 12 can be used to adjust the low temperature and thereby adjust the thickness of the protective film covering the surface 54a of the wafer 54. For example, as shown in Figure 6, the temperature of the liquid resin, the viscosity of the liquid resin, and the thickness of the protective film to be covered on the wafer 54 are determined in advance. In the example shown in Figure 6, when the temperature of the liquid resin is 7°C, the thickness of the protective film covered on the wafer 54 is 2.2 μm, and when the temperature of the liquid resin is 25°C, the thickness of the protective film covered on the wafer 54 is 1.6 μm. In this way, the temperature and viscosity of the liquid resin and the thickness of the protective film are determined in advance, and the temperature of the liquid resin supplied to the wafer 54 is adjusted by the temperature adjustment means 12, thereby adjusting the thickness of the protective film covering the surface 54a of the wafer 54.

[0036] As described above, the liquid resin coating apparatus 2 of this embodiment adjusts the temperature of the liquid resin supplied to the wafer 54 held on the spinner table 14 to a low temperature that is higher than a predetermined value, using the temperature adjustment means 12, so that a protective film of a desired thickness can be coated on the upper surface of the wafer 54. [Explanation of Symbols]

[0037] 2: Liquid resin coating device 4: Table method 6: Liquid resin nozzle 6a: Spray nozzle of liquid resin nozzle 8: Liquid resin containment means 10: Communication means 12: Temperature adjustment means 12a: Peltier element 14: Spinner Table 20: Chamber 54: Waha 54a: Wafer surface 54b: Back side of the wafer 56: Devices 58: Planned division line

Claims

1. A liquid resin coating apparatus for coating the upper surface of a wafer with a liquid resin, The system includes a table means equipped with a spinner table that can hold and rotate a wafer, a liquid resin nozzle for dispensing liquid resin onto the upper surface of the wafer held on the spinner table, a liquid resin containment means containing the liquid resin, a communication means connecting the liquid resin nozzle and the liquid resin containment means, and a temperature control means. The temperature adjustment means is a liquid resin coating apparatus that adjusts the temperature to a low temperature at which the viscosity of the liquid resin supplied to the wafer held on the spinner table becomes higher than a predetermined value.

2. The table means comprises a chamber surrounding the spinner table, The liquid resin coating apparatus according to claim 1, wherein the temperature adjustment means adjusts the atmosphere inside the chamber to the low temperature.

3. The liquid resin coating apparatus according to claim 2, wherein the temperature adjustment means adjusts the temperature of the liquid resin in the liquid resin containment means and the communication means to a high temperature at which the viscosity of the liquid resin becomes lower than a predetermined value, and adjusts the temperature of the liquid resin discharged from the liquid resin nozzle to the low temperature.

4. The liquid resin coating apparatus according to any one of claims 1 to 3, wherein the liquid resin is a water-soluble resin PVA, the low temperature at which the viscosity of the liquid resin becomes higher than the predetermined value is 7°C or lower, and the high temperature at which the viscosity of the liquid resin becomes lower than the predetermined value is 25°C or higher.

5. The liquid resin coating apparatus according to claim 1, wherein a plurality of devices are formed on the upper surface of the wafer, and device regions are demarcated by lines designated for division.

6. The liquid resin coating apparatus according to claim 1, wherein the temperature adjustment means adjusts the low temperature to adjust the thickness of the protective film covering the wafer.

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