Resin sheet, resin sheet manufacturing method, and resin coating method

Abstract

To provide a resin sheet which is capable of sufficiently absorbing ruggedness on a substrate surface and is unlikely to remain on the substrate when peeled.SOLUTION: Provided is a resin sheet for protecting a substrate by coating a surface of the substrate. The resin sheet comprises a flexible resin coating layer provided on an outer surface and a liquid resin layer enclosed by the resin coating layer and is deformable and curable by applying energy from outside. Also provided is a manufacturing method of a resin sheet which is capable of protecting a substrate by being deformed and coating a surface of the substrate and is curable by applying energy from outside. The manufacturing method includes: a liquid resin disposing step of disposing a liquid resin, which is curable by applying energy from outside, on a flat surface; and a surface curing step of forming a resin coated layer by curing only an outer peripheral surface of the liquid resin by applying energy of such a strength that the liquid resin is not entirely cured and making the non-cured liquid resin remain inside the resin coated layer.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a resin sheet capable of covering a surface of a substrate such as a semiconductor wafer in order to protect the surface of the substrate, a method for producing the resin sheet, and a method for coating the surface of a substrate with a resin. [Background technology]

[0002] Device chips used in electronic devices such as mobile phones and computers are formed by grinding a substrate on which a number of devices are arranged on the surface from the back side to thin it, and dividing the substrate into individual devices. Grinding of the substrate is performed by a grinding device. In the grinding device, the substrate is held on a chuck table with the back side exposed upward, and a grinding wheel moving on a circular orbit is brought into contact with the back side of the substrate to grind the substrate. At this time, in order to protect the front side of the substrate, a protective member having a base layer and an adhesive layer laminated thereon is attached in advance to the front surface of the substrate.

[0003] Patterns constituting devices and wiring are disposed on the surface side of the substrate. In addition, bumps serving as electrodes for devices may be formed in advance on the surface side of the substrate. In other words, uneven shapes such as various patterns and bumps are formed on the surface of the substrate.

[0004] If the unevenness of the surface of the substrate is large, the unevenness is not sufficiently absorbed by the adhesive layer when the protective member is attached to the surface of the substrate, and the fixing of the protective member becomes unstable. In addition, the surface of the protective member on the base layer side is not flat, and the substrate is not supported uniformly by the chuck table of the grinding device. If the substrate is ground in this state, the back surface of the substrate will not be flat.

[0005] Therefore, a method was developed in which liquid resin is supplied onto a sheet, the substrate is placed on the liquid resin with the surface side of the substrate facing downwards, the substrate is pressed from above to cause the liquid resin to penetrate into the unevenness of the substrate, and the liquid resin is hardened to form a protective member (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2013-175647 A [Patent Document 2] JP 2017-50536 A Summary of the Invention [Problem to be solved by the invention]

[0007] For example, if the liquid resin is an ultraviolet curable resin, if the liquid resin is irradiated with excessive ultraviolet light when curing the liquid resin, the adhesive strength of the liquid resin decreases and the resin layer formed becomes more likely to peel off. On the other hand, if the amount of ultraviolet light irradiation is too small, the liquid resin does not cure sufficiently. Therefore, it is desirable to irradiate the liquid resin with ultraviolet light under appropriate irradiation conditions.

[0008] However, especially when the surface of the substrate has large irregularities, it is not easy to uniformly and appropriately cure the liquid resin over the entire surface, and uncured areas tend to remain in the liquid resin in contact with the surface of the substrate. In this case, when the resin disposed on the surface of the substrate is peeled off after processing the substrate, some of the resin tends to remain on the surface. On the other hand, when ultraviolet light is irradiated so that the entire area of ​​the liquid resin in contact with the surface of the substrate is sufficiently cured, some of the resin is overcured, and the resin is likely to peel off during processing of the substrate.

[0009] It is also possible to consider a method in which a resin sheet is arranged on the surface of the substrate in advance so as to conform to the uneven shape of the surface of the substrate, liquid resin is brought into contact with the surface of the substrate through the resin sheet, and the substrate is pressed from above to harden the liquid resin. In this case, since the liquid resin does not directly contact the surface of the substrate, the resin does not remain on the surface when it is peeled off from the surface of the substrate. However, it requires the cost of preparing the resin sheet, and the technique and effort of arranging the resin sheet so as to conform to the uneven shape of the surface of the substrate.

[0010] The present invention has been made in consideration of such problems, and an object of the present invention is to provide a resin sheet that can fully absorb the unevenness when placed on a substrate having unevenness and that is unlikely to remain on the substrate when peeled off, as well as a method for manufacturing such a resin sheet and a method for resin coating. [Means for solving the problem]

[0011] According to one aspect of the present invention, there is provided a resin sheet that covers the surface of a substrate to protect the substrate, the resin sheet having a flexible resin coating layer provided on the outer surface and a liquid resin layer surrounded by the resin coating layer, and being deformable and hardenable by the application of energy from the outside.

[0012] Preferably, the resin coating layer comprises a cured first resin material, and the liquid resin layer comprises an uncured first resin material.

[0013] Also preferably, the energy is ultraviolet light or heat.

[0014] According to another aspect of the present invention, there is provided a method for manufacturing a resin sheet that is capable of deforming to cover the surface of a substrate to protect the substrate and that can be hardened by the application of energy from an outside, the method comprising: a liquid resin disposing step of disposing a liquid resin that can be hardened by the external application of energy on a flat surface; and a surface hardening step of hardening only the outer peripheral surface of the liquid resin by externally applying energy of a strength that does not harden the liquid resin as a whole to form a resin coating layer, and leaving the liquid resin unhardened inside the resin coating layer.

[0015] Preferably, the liquid resin is an ultraviolet curable resin or a heat curable resin.

[0016] According to yet another aspect of the present invention, there is provided a resin coating method for a substrate having an uneven surface, comprising the steps of: preparing a resin sheet by applying to a liquid resin an energy having a strength such that the entire resin does not harden, thereby leaving the liquid resin inside the resin and hardening only the outer peripheral surface; a resin coating step of conforming the resin sheet prepared in the resin sheet preparation step to the unevenness of the substrate and coating the surface of the substrate with the resin sheet; and a resin curing step of applying, after the resin coating step, the energy to the resin sheet coated on the substrate from the outside, thereby curing the entire resin sheet.

[0017] Preferably, the method further comprises, after the resin coating step, a processing step of processing the back surface of the substrate, and a peeling step of peeling off the resin sheet that has coated the substrate and cured, from the substrate.

[0018] Also, preferably, in the processing step, the back surface of the substrate is ground using a grinding wheel equipped with a grinding stone.

[0019] Preferably, the resin is an ultraviolet curable resin or a thermosetting resin. Effect of the Invention

[0020] In the resin sheet, the manufacturing method of the resin sheet, and the resin coating method according to one embodiment of the present invention, the resin sheet is formed to have a resin coating layer on the outer surface and a liquid resin layer surrounded by the resin coating layer, and is placed on a substrate having projections and recesses. When the resin sheet placed on the substrate is pressed from above, the resin sheet deforms to conform to the projections and recesses. Since the resin sheet has a freely deformable liquid resin layer inside, it can deform to fully absorb the projections and recesses on the surface of the substrate.

[0021] When energy is applied from the outside in this state so as to harden the liquid resin layer of the resin sheet, the entire resin sheet hardens appropriately and the resin sheet begins to function as a protective member.

[0022] Since the outer surface of the resin sheet is cured before the resin sheet is placed on the substrate, there is no uncured area in the entire area of ​​the resin sheet that contacts the uneven shape of the substrate. Therefore, when the resin sheet is finally peeled off from the substrate, no resin remains on the surface of the substrate. In addition, since the outer surface of the resin sheet is cured in advance, there is no need to irradiate excessive energy such as ultraviolet rays to cure the resin sheet that has entered the uneven shape of the substrate. Therefore, the resin is not cured excessively, and peeling of the resin during processing of the substrate is unlikely to occur.

[0023] Therefore, according to one aspect of the present invention, there is provided a resin sheet that can sufficiently absorb the unevenness when placed on a substrate having unevenness and that is not likely to remain on the substrate when peeled off, as well as a method for manufacturing the resin sheet and a method for resin coating. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1A is a cross-sectional view that typically shows a liquid resin applying step, and FIG. 1B is a cross-sectional view that typically shows a surface hardening step. [Diagram 2] FIG. 2(A) is a cross-sectional view showing a resin sheet having a hardened resin coating layer on its outer surface, and FIG. 2(B) is a cross-sectional view showing a resin sheet placed on a substrate having irregularities. [Diagram 3] FIG. 3(A) is a cross-sectional view that typically shows a resin coating step, and FIG. 3(B) is a cross-sectional view that typically shows a resin curing step. [Figure 4] FIG. 4(A) is a cross-sectional view that typically shows a processing step, and FIG. 4(B) is a cross-sectional view that typically shows a peeling step. [Diagram 5] FIG. 5(A) is a flow chart showing the flow of each step in the method for producing a resin sheet, and FIG. 5(B) is a flow chart showing the flow of each step in the resin coating method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] An embodiment according to one aspect of the present invention will be described with reference to the attached drawings. In the resin sheet, the manufacturing method of the resin sheet, and the resin coating method according to this embodiment, the resin sheet has a cured resin coating layer on the outer surface. Uncured liquid resin is contained inside the resin coating layer. The resin sheet is then placed on a substrate having an uneven surface, pressed from above, and cured by applying energy to the resin sheet, becoming a protective member for the substrate. First, the substrate on which the resin sheet is disposed as a protective member will be described.

[0026] 2(B) and the like include a cross-sectional view that illustrates the substrate 5. The substrate 5 is, for example, a wafer made of a material such as Si (silicon), SiC (silicon carbide), GaN (gallium nitride), GaAs (gallium arsenide), or other semiconductor material. Alternatively, the substrate 5 is a substantially disk-shaped substrate made of a material such as sapphire, glass, or quartz.

[0027] A plurality of mutually intersecting division lines are set on the front surface 5a of the substrate 5. Devices 7 such as ICs (Integrated Circuits) and LSIs (Large Scale Integrations) are formed in each area partitioned by the division lines. The substrate 5 is thinned by grinding from the back surface 5b side, and is divided along the division lines to form individual device chips.

[0028] A plurality of protruding parts called bumps (not shown) made of metal may be provided on the surface 5a of the substrate 5. The bumps are electrically connected to the devices 7, and function as electrodes for inputting and outputting electrical signals to the devices 7 when the substrate 5 is divided into device chips. The bumps are made of a metal material such as gold, silver, copper, or aluminum. However, the surface 5a of the substrate 5 does not necessarily have to have bumps.

[0029] The substrate 5 whose surface 5a is covered with resin is not limited to this. For example, it may be a package substrate formed by sealing a plurality of devices arranged on a plane with sealing resin. By grinding the sealing resin on the back side of the package substrate to thin the package substrate and dividing the package substrate into individual devices, individual device chips of a predetermined thickness sealed with sealing resin can be formed. Since bumps that become electrodes of the individual devices are formed on the surface of the package substrate, the surface of the package substrate is not flat but has irregularities.

[0030] When grinding the substrate 5 from the back surface 5b side, a protective member is attached to the front surface 5a side in advance to protect the front surface 5a side. Conventionally, when the unevenness of the front surface 5a of the substrate 5 is small, a tape-like protective member having a base layer and an adhesive layer laminated thereon has been attached to the front surface 5a of the substrate 5. The exposed surface (the surface on the base layer side) of the protective member attached to the substrate 5 is flat, and when the substrate 5 is placed on a support table (chuck table) with the exposed surface facing downward, the substrate 5 is appropriately supported.

[0031] However, if the unevenness on the front surface 5a side of the substrate 5 becomes large, the adhesive layer of the protective member cannot fully absorb the unevenness, and the protective member attached to the substrate 5 deforms, causing the exposed surface on the base layer side to become non-flat. In this case, when the substrate 5 is carried into the grinding device, the substrate 5 is not properly supported on the support table, and when the substrate 5 is ground from the back surface 5b side, the back surface 5b of the substrate 5 does not become non-flat. Therefore, it is conceivable to supply a liquid resin onto the front surface 5a of the substrate 5 and harden the liquid resin to form the protective member.

[0032] For example, liquid resin is supplied onto a sheet, the surface 5a of the substrate 5 faces the liquid resin, the substrate 5 is placed on the liquid resin, the substrate 5 is pressed from above, and then the liquid resin is cured. If an ultraviolet-curable resin is used as the liquid resin, the liquid resin can be cured with ultraviolet light. However, if the liquid resin is irradiated with excessive ultraviolet light, the adhesive strength of the liquid resin decreases, and the formed resin layer becomes more likely to peel off. On the other hand, if the amount of ultraviolet light irradiated is too small, the liquid resin does not cure sufficiently.

[0033] In particular, it is not easy to sufficiently harden the liquid resin that has entered the recesses in the region in contact with the surface 5a of the substrate 5 having an uneven surface 5a. If uncured liquid resin remains on the surface 5a of the substrate 5, the resin is likely to remain on the surface 5a when the protective member is finally peeled off from the substrate 5. On the other hand, if the liquid resin that has entered the recesses is irradiated with ultraviolet light so as to sufficiently harden the liquid resin, the liquid resin is partially over-hardened, and the protective member is likely to peel off during processing of the substrate 5.

[0034] Therefore, a resin sheet according to the present embodiment, which will be described below, is used. FIG. 2(A) and the like include a cross-sectional view that shows a schematic diagram of the resin sheet 3 according to the present embodiment. The resin sheet 3 has a flexible resin coating layer 3a provided on the outer surface, and a liquid resin layer 3b surrounded by the resin coating layer 3a. The resin sheet 3 is deformable and can be hardened by applying energy from the outside. The resin sheet 3 covers the surface 5a of the substrate 5 and has a function of protecting the substrate 5.

[0035] Next, each step of the manufacturing method of the resin sheet 3 will be described. Fig. 5(A) is a flow chart showing the flow of each step of the manufacturing method of the resin sheet 3. First, a liquid resin disposing step S11 is performed. Fig. 1(A) is a cross-sectional view showing a schematic diagram of the liquid resin disposing step S11. In the liquid resin disposing step S11, a liquid resin 1 that can be hardened by applying energy from the outside is disposed on a flat surface 2a.

[0036] The liquid resin 1 is, for example, an ultraviolet curable resin or a thermosetting resin. However, the liquid resin 1 is not limited to this, and may be formed of a resin material that can be cured by other energy applied from the outside. Hereinafter, the resin sheet 3 according to this embodiment and its manufacturing method will be described using the case where the liquid resin 1 is an ultraviolet curable resin as an example.

[0037] In the liquid resin disposing step S11, a plate 2 having a flat upper surface is prepared. The plate 2 is preferably formed of a material that is permeable to energy capable of curing the liquid resin 1. When the liquid resin 1 is an ultraviolet curing resin, the plate 2 is preferably formed of a material that is permeable to ultraviolet light. The plate 2 is formed of a material such as polyolefin, acrylic, or glass.

[0038] The liquid resin 1 is supplied to the flat surface 2a of the plate 2 by, for example, a resin supplying device having a supply nozzle 4. The liquid resin 1 is, for example, an acrylate-based, epoxy-based, or polyene-polythiol-based ultraviolet curing resin.

[0039] The liquid resin 1 has fluidity as a liquid resin until it is exposed to ultraviolet light, and hardens when it is irradiated with ultraviolet light under specified conditions. When the supply nozzle 4 is positioned above the flat surface 2a and the liquid resin 1 is dropped onto the flat surface 2a from the supply nozzle 4, the liquid resin 1 spreads in all directions on the flat surface 2a.

[0040] Next, the surface curing step S12 is performed. FIG. 1(B) is a cross-sectional view that shows the surface curing step S12. FIG. 2(A) includes a cross-sectional view that shows the resin sheet 3 formed by the surface curing step S12. In the surface curing step S12, energy (ultraviolet rays) of an intensity that does not cure the entire liquid resin 1 is applied from the outside. This cures only the outer peripheral surface of the liquid resin 1 to form a resin coating layer 3a, and leaves the uncured liquid resin 1 (liquid resin layer 3b) inside the resin coating layer 3a.

[0041] As shown in FIG. 1(B), in the surface curing step S12, ultraviolet light sources 6a and 6b are disposed as energy imparting units above the plate 2 on which the liquid resin 1 is disposed on the flat surface 2a, and below the plate 2. The ultraviolet light sources 6a and 6b are, for example, ultraviolet fluorescent lamps or ultraviolet LEDs. When the ultraviolet light source 6a is operated, ultraviolet light is irradiated onto the liquid resin 1 from the upper surface side of the liquid resin 1. When the ultraviolet light source 6b is operated, ultraviolet light is irradiated onto the liquid resin 1 from the lower surface side through the plate 2.

[0042] In the surface curing step S12, it is preferable that the liquid resin 1 is irradiated with ultraviolet light under irradiation conditions weaker than those of the ultraviolet light irradiated onto the resin sheet 3 in the resin curing step S23 described below. Details will be described later. Increasing the illuminance and irradiation time of the ultraviolet light allows the curing of the liquid resin 1 to progress deeper into the interior. In other words, the thickness of the formed resin coating layer 3a is determined by the ultraviolet light irradiation conditions.

[0043] The thickness and area of ​​the resin sheet 3 to be formed are determined by the properties such as viscosity of the liquid resin 1 supplied to the plate 2 in the liquid resin dispensing step S11, and the supply amount of the liquid resin 1. The area of ​​the resin sheet 3 is preferably determined to be approximately the same as the area of ​​the substrate 5 on which the resin sheet 3 is disposed. The thickness of the resin sheet 3 is preferably set to a thickness that can sufficiently absorb the uneven shape of the surface 5a of the substrate 5.

[0044] For example, the total thickness of the resin sheet 3 to be formed is preferably about 5 mm. The thickness of the resin coating layer 3a is preferably about 0.5 mm. However, the resin sheet 3 to be formed is not limited to this, and the thickness, area, etc. of the resin sheet 3 may be appropriately determined depending on the application.

[0045] To briefly explain the resin sheet 3 thus formed, only the outer surface of the liquid resin 1 is cured to become the resin coating layer 3a, and the liquid resin 1 that is not cured is surrounded by the resin coating layer 3a to become the liquid resin layer 3b. In other words, the resin coating layer 3a of the resin sheet 3 contains the cured first resin material, and the internal liquid resin layer 3b contains the first resin material that is not cured.

[0046] The boundary between the resin coating layer 3a and the liquid resin layer 3b of the resin sheet 3 is not necessarily clear. In addition, the ultraviolet irradiation intensity differs between the area close to the outer surface of the liquid resin 1 and the area far from the outer surface, so the resin coating layer 3a is not necessarily formed homogeneously. All areas of the liquid resin 1 that have been altered even slightly can be called the resin coating layer 3a. Alternatively, only the area of ​​the liquid resin 1 that has been most altered can be called the resin coating layer 3a. It can also be considered that the resin coating layer 3a has multiple layers with different degrees of alteration.

[0047] The resin coating layer 3a of the resin sheet 3 can be deformed by application of an external force, and can expand within a certain limit. Since the liquid resin layer 3b maintains its fluidity, when the resin coating layer 3a is deformed, the internal liquid resin layer 3b also deforms following the deformation of the resin coating layer 3a. In other words, the resin sheet 3 is deformable. Furthermore, by further applying energy such as ultraviolet light from the outside to the resin sheet 3, the internal liquid resin layer 3b can be hardened, and the entire sheet can be hardened.

[0048] The manufactured resin sheet 3 can be used to cover, for example, the surface 5a of a substrate 5 having projections and recesses, forming a protective member for protecting the surface 5a. Next, a method for resin-coating a substrate will be described as a method for using the manufactured resin sheet 3. Fig. 5(B) is a flow chart showing the flow of each step of the resin-coating method.

[0049] In the resin coating method, first, a resin sheet preparation step S21 is performed. In this resin sheet preparation step S21, a resin sheet 3 including a resin coating layer 3a and a liquid resin layer 3b is prepared. Alternatively, in the resin sheet preparation step S21, the above-mentioned method for manufacturing the resin sheet 3 is performed. That is, in the resin sheet preparation step S21, energy (ultraviolet rays) of such intensity that the entire resin does not harden is applied to the liquid resin (liquid resin 1) from the outside, leaving the liquid resin inside the resin and hardening only the outer peripheral surface, thereby obtaining the resin sheet 3.

[0050] In the resin coating method, next, a resin coating step S22 is performed in which the surface 5a of the substrate 5 is coated with the resin sheet 3 prepared in the resin sheet preparation step S21. In the resin coating step S22, in the first step, the resin sheet 3 is placed on the surface 5a of the substrate 5. In the second step, the resin sheet 3 placed on the substrate 5 is pressed from above. Fig. 2(B) is a cross-sectional view that typically shows the substrate 5 with the resin sheet 3 placed on the surface 5a. Fig. 3(A) is a cross-sectional view that typically shows the state in which the resin sheet 3 placed on the substrate 5 is pressed from above.

[0051] The substrate 5 has an uneven surface 5a formed by the devices 7 and bumps (not shown). Therefore, the resin sheet 3 does not come into sufficient contact with the uneven surface simply by being placed on the surface 5a. Therefore, the resin sheet 3 is pressed from above in order to deform the resin sheet 3 to conform to the uneven surface and bring the resin sheet 3 into contact with the surface 5a over a sufficiently wide area.

[0052] In the resin coating step S22, a pressing device 8 capable of pressing from above the resin sheet 3 placed on the substrate 5 is preferably used. The substrate 5 is preferably placed in advance on a flat table 10a of the pressing device 8. The pressing device 8 includes a pressing plate 10b that has a bottom surface parallel to the top surface of the table 10a and can descend toward the table 10a.

[0053] As shown in Fig. 2(B), in the first stage of the resin coating step S22, the resin sheet 3 is placed on the substrate 5 so as to cover the entire surface 5a of the substrate 5. Then, as shown in Fig. 3(A), in the second stage of the resin coating step S22, the pressing plate 10b is lowered and the pressing plate 10b presses the resin sheet 3 from above. Then, the resin sheet 3 is pressed against the surface 5a of the substrate 5, and the resin sheet 3 deforms in the area in contact with the surface 5a to follow the unevenness of the surface 5a of the substrate 5.

[0054] More specifically, at this time, the resin coating layer 3a of the resin sheet 3 partially expands or contracts to follow the unevenness, and the liquid resin layer 3b flows inside the resin sheet 3 in accordance with the deformation of the resin coating layer 3a. Here, it is preferable that the thickness of the resin coating layer 3a of the resin sheet 3 is determined within a range in which no damage occurs when the resin sheet 3 deforms to follow the uneven shape of the surface 5a of the substrate 5.

[0055] The resin sheet 3 can be deformed within the range permitted by the durability of the resin coating layer 3a, and the resin sheet 3 according to this embodiment, which has the liquid resin layer 3b therein, has a larger margin of deformation compared to a case in which the liquid resin layer 3b is not present inside the resin sheet 3. In the case in which the liquid resin layer 3b is not present, when the resin sheet 3 is locally deformed, the restoring force generated may be large or large internal stress may be generated, causing localized damage to the resin sheet 3. In other words, the resin sheet 3 according to this embodiment can be deformed relatively easily.

[0056] After the resin coating step S22, a resin curing step S23 is carried out to cure the entire resin sheet 3. Fig. 3(B) is a cross-sectional view showing a schematic diagram of the resin curing step S23. In the resin curing step S23, energy is applied from the outside to the resin sheet 3 that has coated the substrate 5, and the entire resin sheet 3 is cured. For example, if the resin that constitutes the resin sheet 3 is an ultraviolet curable resin, the resin sheet 3 is irradiated with ultraviolet light in the resin curing step S23.

[0057] Here, the pressing plate 10b is preferably formed of a material that transmits ultraviolet light so that the resin sheet 3 can be irradiated with ultraviolet light through the pressing plate 10b. For example, the pressing plate 10b is formed of a material such as polyolefin, acrylic, or glass. The pressing device 8 also includes an ultraviolet light source 12 as an energy imparting unit. The ultraviolet light source 12 is, for example, an ultraviolet fluorescent lamp or an ultraviolet LED. When the ultraviolet light source 12 is activated, the resin sheet 3 is irradiated with ultraviolet light through the pressing plate 10b.

[0058] In the resin curing step S23, it is preferable to irradiate the resin sheet 3 with ultraviolet light under irradiation conditions stronger than those used for irradiating the liquid resin 1 in the surface curing step S12 so that the liquid resin layer 3b of the resin sheet 3 can be completely cured.

[0059] When the entire resin sheet 3 is cured, a protective member 9 made of resin is disposed on the front surface 5a of the substrate 5. The protective member 9 has a function of protecting the front surface 5a when the substrate 5 is processed from the rear surface 5b side. As described later, the substrate 5 is supported via the protective member 9 when the rear surface 5b is processed. Therefore, in order to suppress the inclination of the substrate 5 being processed, the pressing device 8 used in the resin curing step S23 needs to have its orientation adjusted with high precision so that the bottom surface of the pressing plate 10b that defines the upper surface of the protective member 9 is parallel to the rear surface 5b.

[0060] The substrate 5 with the protective member 9 disposed on the front surface 5a is then processed from the back surface 5b. Next, the processing step S24 performed after the resin curing step S23 will be described. Fig. 4(A) is a cross-sectional view showing the processing step S24. In the processing step S24, for example, the substrate 5 is ground from the back surface 5b side to be thinned.

[0061] The grinding device 16 that grinds the substrate 5 includes a chuck table 14 that can hold the substrate 5 by suction via a protective member 9, and a grinding wheel 22 that grinds the substrate 5 held by suction on the chuck table 14.

[0062] Chuck table 14 has a disk-shaped porous member (not shown) at the center of its upper surface, the member having a diameter approximately equal to that of substrate 5, and a suction source (not shown) is connected to this porous member via a suction path (not shown). When substrate 5 is placed on chuck table 14 with front surface 5a facing downward via protective member 9 and the suction source is operated, negative pressure acts on substrate 5 via the suction path and porous member, and substrate 5 is sucked and held on chuck table 14. The upper surface of the porous member of chuck table 14 functions as holding surface 14a.

[0063] The grinding wheel 22 has an annular wheel base 24. The wheel base 24 is made of a metal such as aluminum, and has a diameter corresponding to the diameter of the substrate 5 to be processed. A plurality of grinding wheels 26 arranged in an annular shape are provided on the outer periphery of the lower surface (bottom surface) side of the wheel base 24. Each grinding wheel 26 is formed by mixing abrasive grains such as diamond or cBN (cubic boron nitride) with a binder such as vitrified or resinoid, and sintering the mixture.

[0064] The grinding wheel 22 is fixed to the lower surface of a wheel mount 20 connected to the lower end of a spindle 18 that constitutes a rotation shaft. A rotation drive source such as a motor that rotates the spindle 18 around a rotation axis that is aligned in a direction substantially perpendicular to the holding surface 14a is connected to the upper end of the spindle 18. The chuck table 14 is also rotatable around an axis perpendicular to the holding surface 14a.

[0065] When grinding the substrate 5, the chuck table 14 is rotated and the spindle 18 is rotated, the spindle 18 is lowered, and the grinding wheel 26 moving on the circular track is brought into contact with the back surface 5b of the substrate 5. The substrate 5 is then ground and gradually thinned. Thereafter, when the substrate 5 reaches a predetermined thickness, the descent of the spindle 18 is stopped, and grinding of the substrate 5 is completed. During this time, the front surface 5a side of the substrate 5 is protected by the protective member 9. Thereafter, the suction holding of the substrate 5 by the chuck table 14 is released, and the substrate 5 is carried out of the grinding device 16.

[0066] The processing of the substrate 5 performed in the processing step S24 is not limited to grinding. The substrate 5 may be polished from the back surface 5b side, or may be divided into each device 7. After the processing step S24 is performed, a peeling step S25 is performed in which the resin sheet 3 (protective member 9) covering the front surface 5a of the substrate 5 is peeled off from the substrate 5. FIG. 4(B) is a cross-sectional view that typically shows the peeling step S25.

[0067] When performing the peeling step S25, the protective member 9 may be hardened in advance by irradiating it with high-intensity ultraviolet light in order to make it easier to peel off. Alternatively, the protective member 9 may be softened by heating. When the peeling step S25 is performed, the processed substrate 5 is obtained.

[0068] As described above, in the resin coating method according to this embodiment, the resin sheet 3, the outer surface of which has been cured in advance, is disposed on the surface 5a of the substrate 5. That is, the already cured resin (resin coating layer 3a) fills the recesses in the surface 5a. Therefore, there is no need to irradiate the resin sheet 3 with ultraviolet light excessively, and the protective member 9, which is unlikely to peel off, can be disposed on the surface 5a of the substrate 5, and when the protective member 9 is peeled off from the substrate 5 at the end of processing of the substrate 5, the resin is unlikely to remain on the surface 5a.

[0069] In other words, by using the resin sheet 3, the surface 5a of the substrate 5 can be covered with the resin (protective member 9) while sufficiently absorbing the irregularities of the surface 5a. When the resin (protective member 9) is subsequently peeled off from the substrate 5, the resin is unlikely to remain on the surface 5a.

[0070] In the above embodiment, the liquid resin 1 (such as the resin sheet 3) is made of an ultraviolet curable resin that is cured by ultraviolet light. However, the liquid resin 1 (such as the resin sheet 3) that is cured by application of energy may be cured by application of energy other than ultraviolet light from the outside.

[0071] For example, the liquid resin 1 may be a thermosetting resin that hardens when heated. Even in this case, if the liquid resin 1 is heated under heating conditions that harden only the outer surface of the liquid resin 1 and not the inside, a resin sheet 3 including a resin coating layer 3a and a liquid resin layer 3b can be manufactured. That is, in the surface hardening step S12, heat is applied as energy to the liquid resin 1 using a heat source such as a heater or an infrared lamp, thereby hardening only the outer peripheral surface of the liquid resin 1.

[0072] In this case, the surface 5a of the substrate 5 is covered with the formed resin sheet 3, the resin sheet 3 is pressed from above to deform so as to follow the surface 5a, and then the resin sheet 3 is heated under conditions that allow the entire resin sheet 3 to harden, whereby the surface 5a of the substrate 5 is covered with the protective member 9. That is, in the resin hardening step S23, heat is applied as energy to the resin sheet 3 using a heat source such as a heater or an infrared lamp, thereby hardening the liquid resin layer 3b.

[0073] In addition, the structures, methods, and the like according to the above-described embodiments and modified examples can be modified as appropriate without departing from the scope of the present invention. [Explanation of symbols]

[0074] 1 Liquid resin 3 Resin sheet 3a Resin coating layer 3b Liquid resin layer 5 Substrate 5a surface 5b Back 7 Devices 9 Protective materials 2 Plate 2a flat surface 4 Supply Nozzle 6a,6b UV source 8 Pressing device 10a Table 10b Pressure plate 12 UV source 14 Chuck table 14a Holding surface 16 Grinding equipment 18 Spindle 20 Wheel mount 22 Grinding Wheel 24 Wheel base 26 Grinding Wheel

Claims

1. A resin sheet that covers a surface of a substrate to protect the substrate, a flexible resin coating layer provided on an outer surface; a liquid resin layer surrounded by the resin coating layer, A resin sheet which is deformable and can be hardened by application of energy from outside.

2. the resin coating layer has a hardened first resin material; 2. The resin sheet according to claim 1, wherein the liquid resin layer comprises the first resin material which is not cured.

3. 3. The resin sheet according to claim 1, wherein the energy is ultraviolet light or heat.

4. A method for producing a resin sheet that can be deformed to cover a surface of a substrate to protect the substrate and can be hardened by applying energy from an outside, comprising: a liquid resin disposing step of disposing a liquid resin that can be hardened by applying the energy from outside on a flat surface; a surface curing step of curing only the outer peripheral surface of the liquid resin by externally applying energy of an intensity that does not cure the entire liquid resin to form a resin coating layer, and leaving the liquid resin uncured inside the resin coating layer; A method for producing a resin sheet, comprising the steps of:

5. 5. The method for producing a resin sheet according to claim 4, wherein the liquid resin is an ultraviolet curable resin or a thermosetting resin.

6. A method for resin coating a substrate having an uneven surface with a resin sheet, comprising the steps of: a resin sheet preparation step of applying energy from the outside to a liquid resin such that the entire resin does not harden, leaving the liquid resin inside the resin and hardening only the outer peripheral surface of the resin sheet; a resin coating step of coating a surface of the substrate with the resin sheet by aligning the resin sheet prepared in the resin sheet preparation step with the unevenness of the substrate; A resin coating method characterized by comprising, after the resin coating step, a resin curing step of applying energy from outside to the resin sheet coated on the substrate to cure the entire resin sheet.

7. a processing step of processing the back surface of the substrate after the resin coating step; 7. The resin coating method according to claim 6, further comprising a peeling step of peeling off the resin sheet, which has been coated on the substrate and cured, from the substrate.

8. 8. The resin coating method according to claim 7, wherein the processing step includes grinding the back surface of the substrate using a grinding wheel equipped with a grinding stone.

9. 9. The resin coating method according to claim 6, wherein the resin is an ultraviolet curable resin or a thermosetting resin.

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