JP2012115911A - Substrate grinding method and semiconductor element manufactured by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate grinding method by which a substrate is ground easily.SOLUTION: The substrate grinding method includes the process of placing a substrate 100 on one main surface of an substrate holding part 800 of elastic tabular form containing cavities communicatively connecting the outer surface to the interior, and vacuum sucking the substrate 100 via the substrate holding part 800 to fix the same as one main surface of the substrate holding part 800 is deformed into a shape along a surface shape of the substrate 100 by deaerating the substrate holding part 800 from its another main surface. The substrate grinding method also includes the process of grinding a main surface 110 of the substrate 100 that is opposite to its another main surface 120 in contact with the substrate holding part 800 as the substrate 100 is fixed via the substrate holding part 800, and the process of canceling the vacuum suction following the grinding process.

Description

  The present invention relates to a method for grinding a substrate and a semiconductor device manufactured using the same.

  There exists patent document 1 as a prior art document which disclosed the manufacturing method of the laminated body containing a to-be-ground base material. In the method for manufacturing a laminate including a substrate to be ground described in Patent Document 1, a photocurable adhesive layer is formed on one surface of a substrate, and a photothermal conversion layer is formed on one surface of a substrate holding portion is doing. Laminate the photocurable adhesive layer by irradiating light with the substrate laminated on the substrate holding part so that it is positioned on the surface of the photothermal conversion layer via the photocurable adhesive layer. I'm getting a body. In the state of the laminated body, an ultrathin base material is manufactured by grinding the surface of the substrate.

JP 2004-64040 A

  In the method for producing a laminate including a substrate to be ground described in Patent Document 1, it is necessary to form a photothermal conversion layer and irradiate the photothermal conversion layer with radiant energy after grinding the substrate. Becomes complicated.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for grinding a substrate and a semiconductor device manufactured using the same, which can be performed by a simple method.

  In the first aspect of the substrate grinding method according to the present invention, the step of placing the substrate on one main surface of the flat substrate holding portion including the outer surface and the gap communicating with the inside and having elasticity. And vacuuming the substrate through the substrate holder in a state where one main surface of the substrate holder is deformed so as to follow the surface shape of the substrate by degassing from the other main surface side of the substrate holder. Adsorbing and fixing. The substrate grinding method includes a step of grinding the main surface of the substrate opposite to the main surface in contact with the substrate holding portion in a state where the substrate is fixed via the substrate holding portion, and the grinding step And a step of releasing the vacuum suction.

  Preferably, the thickness of the substrate holding part is 10 μm or more and 500 μm or less. Further, by releasing the vacuum suction, the shape of one main surface of the substrate holding part is restored to the original shape.

  In the second aspect, the substrate grinding method according to the present invention includes a substrate holding part having an adhesive layer that is cured by receiving ultraviolet rays on a flat base material, one main surface of the substrate, and the adhesive layer. And a step of fixing the substrate holding part by vacuum suction of the base material of the substrate holding part to which the substrate is attached. The substrate grinding method includes a step of grinding the other main surface of the substrate in a state where the substrate holding portion is fixed, a step of releasing vacuum suction of the substrate holding portion after the grinding step, After the step of releasing the vacuum suction, a step of irradiating the adhesive layer of the substrate holding part with ultraviolet rays and a step of peeling the substrate holding part and the substrate after the step of irradiating the ultraviolet rays are provided. Preferably, the thickness of the adhesive layer is 1 μm or more and 100 μm or less.

  According to the present invention, the substrate can be ground by a simple method.

It is sectional drawing which shows the state which mounts a board | substrate on a board | substrate holding part in the grinding method of the board | substrate which concerns on Embodiment 1 of this invention. In the same embodiment, it is sectional drawing which shows the state which fixed the board | substrate via the board | substrate holding part. In the same embodiment, it is sectional drawing which shows the state which canceled the vacuum suction after grinding of one main surface of a board | substrate. In the same embodiment, it is sectional drawing which shows the state which mounts the board | substrate turned upside down on a board | substrate holding part. In the same embodiment, it is sectional drawing which shows the state which fixed the board | substrate by which the single side | surface was ground through the board | substrate holding part. In the same embodiment, it is sectional drawing which shows the state which canceled the vacuum suction after grinding the other main surface of a board | substrate. In the same embodiment, it is sectional drawing which shows the state which anneals a board | substrate. In the same embodiment, it is sectional drawing which shows the state which mounts the annealed board | substrate on a board | substrate holding part. In the same embodiment, it is sectional drawing which shows the state which fixed the annealed board | substrate through the board | substrate holding part. In the same embodiment, it is sectional drawing which shows the state which canceled the vacuum suction after the mirror surface finishing of the main surface of a board | substrate. It is sectional drawing which shows the state which bonds a board | substrate and a board | substrate holding part in the grinding method of the board | substrate which concerns on Embodiment 2 of this invention. In the same embodiment, it is sectional drawing which shows the state which fixed the board | substrate via the board | substrate holding part. In the same embodiment, it is sectional drawing which shows the state which canceled the vacuum suction after grinding of one main surface of a board | substrate. In the same embodiment, it is sectional drawing which shows the state which has irradiated the ultraviolet-ray to the contact bonding layer of the board | substrate holding part holding the board | substrate by which the single side | surface was ground. In the same embodiment, it is sectional drawing which shows the state which bonds a board | substrate holding | maintenance part to the main surface where the board | substrate was ground. In the same embodiment, it is sectional drawing which shows the state which fixed the board | substrate which grind | polished one side through the board | substrate holding part. In the same embodiment, it is sectional drawing which shows the state which canceled the vacuum suction after grinding the other main surface of a board | substrate. In the same embodiment, it is sectional drawing which shows the state which has irradiated the ultraviolet-ray to the contact bonding layer of the board | substrate holding part holding the board | substrate with which both surfaces were ground. In the same embodiment, it is sectional drawing which shows the state which anneals a board | substrate. In the same embodiment, it is sectional drawing which shows the state which bonds the annealed board | substrate to a board | substrate holding part. In the same embodiment, it is sectional drawing which shows the state which fixed the annealed substrate via the board | substrate holding | maintenance part. It is sectional drawing which shows the state which canceled the vacuum suction after the mirror surface finishing of the main surface of the board | substrate in the same embodiment. In the same embodiment, it is sectional drawing which shows the state which has irradiated the ultraviolet-ray to the contact bonding layer of the board | substrate holding | maintenance part holding the board | substrate by which mirror finishing was carried out. 2 is an atomic force microscope photograph of a polished surface of a substrate that has been ground by the grinding method of Embodiment 1. 3 is an atomic force microscope photograph of a polished surface of a substrate ground by the grinding method of Embodiment 2.

  Hereinafter, a substrate grinding method according to Embodiment 1 of the present invention and a semiconductor device manufactured using the same will be described with reference to the drawings. In the following description of the embodiments, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a cross-sectional view showing a state in which a substrate is placed on a substrate holder in the substrate grinding method according to Embodiment 1 of the present invention.

  In the present embodiment, as shown in FIG. 1, a sapphire substrate having irregularities on both one main surface 110 and the other main surface 120 of the substrate 100 is prepared. Specifically, the substrate 100 is an As-Cut sapphire substrate formed by being sliced from an ingot. The surface roughness of the main surface of the prepared substrate 100 is about 0.5 μm to several tens of μm. However, the substrate 100 is not limited to a sapphire substrate, and may be, for example, a semiconductor wafer such as silicon or gallium arsenide, a crystal wafer, or a glass substrate.

  The substrate holding unit 800 includes a void communicating with the outer surface and the inside, has an elastic force, and has a flat plate shape. Therefore, by evacuating from the other main surface of the substrate holding unit 800, it is possible to adsorb the material on one main surface of the substrate holding unit 800.

  In this embodiment, the substrate holding unit 800 is a silicon film having a thickness of 100 μm formed with a large number of holes with needles. However, the substrate holding unit 800 is not limited to this, and as the substrate holding unit 800, for example, a plurality of holes having a diameter of about several μm to several tens of μm are formed in a sheet made of polyurethane having a thickness of 10 μm to 500 μm. You may use what you did.

  The substrate holding unit 800 is placed on the vacuum suction plate 400. The vacuum suction plate 400 has a flat plate shape. The vacuum suction plate 400 has a chamfered surface on both the upper and lower surfaces. In this embodiment, the vacuum suction plate 400 is formed of ceramic, but the material of the vacuum suction plate 400 is not limited to this, and may be formed of aluminum or stainless steel, for example.

  One end of a degassing hose 510 is connected to the lower surface of the vacuum suction plate 400. The other end of the degassing hose 510 is connected to the vacuum pump 500. The substrate holding part 800 is formed with a through hole communicating from the upper surface to the lower surface of the portion to which the hose 510 is connected. A large number of through holes are evenly formed at predetermined intervals on the upper surface of the substrate holding unit 800.

  FIG. 2 is a cross-sectional view showing a state in which the substrate is fixed via the substrate holding portion in the present embodiment. As shown in FIG. 2, the vacuum pump 500 is operated with the substrate 100 placed on one main surface of the substrate holder 800. As the vacuum pump 500 is operated, the air in the hose 510 is sucked in the direction of the arrow 520. As a result, air is sucked and degassed from the other main surface side of the substrate holder 800 that is in contact with the upper surface of the vacuum suction plate 400.

  Since the substrate holding part 800 has elasticity, when the substrate 100 in contact with one main surface of the substrate holding part 800 is adsorbed by degassing from the other main surface of the substrate holding part 800, the substrate One main surface of the holding part 800 is deformed so as to follow the surface shape of the other main surface 120 of the substrate 100. The substrate 100 is fixed by vacuum suction through the substrate holding unit 800.

  One main surface 110 of the substrate 100 is ground in a state where the substrate 100 is fixed as described above. In the present embodiment, the surface roughness of one main surface 110 of the substrate 100 is reduced by grinding the grinding wheel 300 from the surface to a depth of several tens to several hundreds of μm while feeding the grinding wheel 300 in the direction of the hollow arrow in the figure. The thickness is about 0.5 μm to about several tens μm before grinding to about 0.1 μm to several μm. In the present embodiment, the metal grinding wheel 300 is used, but a vitrified grinding wheel may be used as the grinding wheel 300.

  FIG. 3 is a cross-sectional view showing a state in which the vacuum suction is released after grinding one main surface of the substrate in the present embodiment. As shown in FIG. 3, after the grinding of one main surface 110 of the substrate 100 is finished, the vacuum suction of the substrate 100 is released by stopping the vacuum pump 500.

  Since the substrate holding portion 800 has elasticity, when the vacuum suction is released, one main surface of the substrate holding portion 800 that has been deformed to conform to the surface shape of the other main surface 120 of the substrate 100. The shape of is restored to its original shape. In other words, the substrate holding unit 800 returns to the original flat shape. Therefore, the substrate holder 800 can be used multiple times. However, the substrate holder 800 does not necessarily need to be restored to its original shape, and a new substrate holder 800 may be used each time.

  FIG. 4 is a cross-sectional view showing a state in which the substrate turned upside down is placed on the substrate holding part in the present embodiment. As shown in FIG. 4, the substrate 100 is placed on one main surface of the substrate holding unit 800 so that one main surface 110 of the ground substrate 100 is in contact with the substrate holding unit 800. The substrate holding unit 800 is placed on the vacuum suction plate 400.

  FIG. 5 is a cross-sectional view showing a state where a substrate whose one side is ground is fixed via a substrate holding part in the present embodiment. As shown in FIG. 5, the vacuum pump 500 is operated in a state where the substrate 100 with one main surface 110 ground is placed on one main surface of the substrate holding unit 800. As the vacuum pump 500 is operated, the air in the hose 510 is sucked in the direction of the arrow 520. As a result, air is sucked and degassed from the other main surface side of the substrate holder 800 that is in contact with the upper surface of the vacuum suction plate 400. As a result, the substrate 100 is fixed by being vacuum-sucked through the substrate holding unit 800.

  With the substrate 100 fixed as described above, the other main surface 120 of the substrate 100 is ground. In the present embodiment, the surface roughness of the other main surface 120 of the substrate 100 is reduced by grinding the grinding wheel 300 from the surface to a depth of several tens of μm to several hundreds of μm while feeding it in the direction of the hollow arrow in the figure. The thickness is about 0.5 μm to about several tens μm before grinding to about 0.1 μm to several μm.

  FIG. 6 is a cross-sectional view showing a state in which vacuum suction is released after grinding of the other main surface of the substrate in the present embodiment. As shown in FIG. 6, after the grinding of the other main surface 120 of the substrate 100 is finished, the vacuum suction of the substrate 100 is released by stopping the vacuum pump 500.

  The substrate 100 whose both main surfaces are ground is annealed in order to relieve the processing stress distortion during grinding. FIG. 7 is a cross-sectional view showing a state in which the substrate is annealed in the present embodiment. As shown in FIG. 7, the residual stress in the substrate 100 a is removed by annealing in a high temperature furnace 700 at a temperature of several thousand hundred degrees C. for several hours to several tens of hours. By annealing, scale adheres to the surface of the substrate 100a. Therefore, the main surface on the side where the semiconductor device is formed is ground again to perform mirror finish.

  FIG. 8 is a cross-sectional view showing a state in which the annealed substrate is placed on the substrate holding part in the present embodiment. As shown in FIG. 8, the substrate 100 a is placed on one main surface of the substrate holder 800. The substrate holding unit 800 is placed on the vacuum suction plate 400.

  FIG. 9 is a cross-sectional view showing a state in which the annealed substrate is fixed via the substrate holding portion in the present embodiment. As shown in FIG. 9, the vacuum pump 500 is operated in a state where the annealed substrate 100 a is placed on one main surface of the substrate holding unit 800. As the vacuum pump 500 is operated, the air in the hose 510 is sucked in the direction of the arrow 520. As a result, air is sucked and degassed from the other main surface side of the substrate holder 800 that is in contact with the upper surface of the vacuum suction plate 400. As a result, the substrate 100a is fixed by being vacuum-sucked through the substrate holding unit 800.

  With the substrate 100a fixed as described above, the substrate 100a is ground. In the present embodiment, the surface roughness of the main surface of the substrate 100 is reduced from 0.5 μm before grinding by grinding the grinding wheel 300 to a depth of several tens of μm from the surface while feeding the grinding wheel 300 in the direction of the hollow arrow in the figure. About a few dozen μm to 0.01 nm-0. Set to about several nm.

  Specifically, the substrate 100a is polished using a metal having a count of 1000 or more, vitrified, or a diamond grindstone. Thereafter, the substrate 100a is polished using a diamond slurry having a particle size of several μm and a surface plate made of copper or tin. Next, the substrate 100a is dry-polished using a polishing cloth. Further, the substrate 100a is polished using silica having a particle size of several tens of nm and a polishing cloth. As a result, the surface roughness of the main surface of the substrate 100 is 0.01 nm to 0. It is about several nm.

  FIG. 10 is a cross-sectional view showing a state in which vacuum suction is released after mirror finishing of the main surface of the substrate in the present embodiment. As shown in FIG. 10, after the mirror-finished substrate 100 a ′ is completely ground, the vacuum pump 500 is stopped to release the vacuum suction of the substrate 100 a ′.

  In the present embodiment, as described above, the substrate 100 is ground without bonding and fixing the substrate 100. Therefore, the substrate 100 can be easily ground, and the manufacturing cost of a semiconductor element manufactured using the substrate 100a 'can be reduced.

  The thickness of the substrate holder 800 is preferably 10 μm or more and 500 μm or less. In this case, the substrate holding unit 800 can be deformed so as to substantially conform to the irregularities having a size of not more than a dozen μm or less of the substrate 100 before grinding, and the substrate 100 can be vacuum-sucked. Since the thickness of 800 is thin, it is easy to form a gap in the substrate holding portion 800, and the fixing force of the substrate 100 when deaerated can be stabilized. Furthermore, by manufacturing the substrate holding unit 800 thinly, the material necessary for manufacturing the substrate holding unit 800 can be reduced, and the manufacturing cost of the substrate holding unit 800 can be reduced.

  Hereinafter, a substrate grinding method according to a second embodiment of the present invention and a semiconductor device manufactured using the same will be described with reference to the drawings.

(Embodiment 2)
In this embodiment, grinding is performed in a state where the substrate is held by the substrate holding portion having an adhesive layer that is cured by receiving ultraviolet rays. In the substrate grinding method of this embodiment, the description of the same parts as those of Embodiment 1 will not be repeated.

  FIG. 11 is a cross-sectional view showing a state in which the substrate and the substrate holding part are bonded together in the substrate grinding method according to the second embodiment of the present invention. As shown in FIG. 11, in this embodiment, the substrate holder 200 has an adhesive layer 220 that is cured by receiving ultraviolet rays on a flat substrate 210.

  In the present embodiment, the substrate 210 is formed using a polyethylene terephthalate resin. However, the base material 210 only needs to be formed of a material that transmits ultraviolet light and is not easily elastically deformed even when a pressure is applied. The base material 210 is an acrylic resin, polycarbonate resin, cycloolefin polymer, polystyrene resin, and funk. It may be formed of a national norbornene resin or the like. The thickness of the substrate 210 is 25 μm to 200 μm. Both main surfaces of the substrate 210 are formed in a planar shape. As the adhesive layer 220, a resin containing an acrylic monomer and a photopolymerization initiator is used. The thickness of the adhesive layer 220 is preferably 1 μm or more and 100 μm. Moreover, as the substrate holding part 200, for example, a surface protection tape for ultraviolet curable back grinding manufactured by Lintec Corporation may be used.

  The substrate 100 is bonded to the substrate holding part 200 so that the other main surface 120 of the substrate 100 and the adhesive layer 220 are in contact with each other. Specifically, the substrate holding unit 200 is bonded to the substrate 100 by pressing the substrate holding unit 200 against the substrate 100 with a roller so that the adhesive layer 220 is embedded in the unevenness of the other main surface 120 of the substrate 100. .

  FIG. 12 is a cross-sectional view showing a state in which the substrate is fixed via the substrate holding portion in the present embodiment. As shown in FIG. 12, the substrate holder 200 is placed on the vacuum suction plate 400 so that the base 210 of the substrate holder 200 to which the substrate 100 is bonded is in contact with the upper surface of the vacuum suction plate 400. Then, the vacuum pump 500 is operated. As the vacuum pump 500 is operated, the air in the hose 510 is sucked in the direction of the arrow 520. As a result, air is sucked and degassed from the substrate 210 side of the substrate holder 200 that is in contact with the upper surface of the vacuum suction plate 400. The substrate holder 200 is fixed by vacuum suction. As a result, the substrate 100 is fixed.

  One main surface 110 of the substrate 100 is ground in a state where the substrate 100 is fixed as described above. In the present embodiment, the surface roughness of one main surface 110 of the substrate 100 is reduced by grinding the grinding wheel 300 from the surface to a depth of several tens to several hundreds of μm while feeding the grinding wheel 300 in the direction of the hollow arrow in the figure. The thickness is about 0.5 μm to about several tens μm before grinding to about 0.1 μm to several μm. In the present embodiment, the metal grinding wheel 300 is used, but a vitrified grinding wheel may be used as the grinding wheel 300.

  FIG. 13 is a cross-sectional view showing a state where the vacuum suction is released after grinding one main surface of the substrate in the present embodiment. As shown in FIG. 13, after the grinding of one main surface 110 of the substrate 100 is finished, the vacuum suction of the substrate holding unit 200 is released by stopping the vacuum pump 500.

  FIG. 14 is a cross-sectional view showing a state in which ultraviolet rays are applied to the adhesive layer of the substrate holding unit that holds the substrate with one side ground in this embodiment. As shown in FIG. 14, the adhesive layer 220 is cured to become an adhesive layer 221 by irradiating the adhesive layer 220 with ultraviolet rays 610 from the ultraviolet irradiation unit 600. In the present embodiment, an ultraviolet high-pressure mercury lamp is used as the ultraviolet irradiation unit 600. However, for example, an ultraviolet LED (Light Emitting Diode) may be used.

  The cured adhesive layer 221 has lost its viscosity. In the cured state, the adhesive layer 221 of the present embodiment has a stronger bonding force with the base material 210 than the bonding force with the substrate 100. Therefore, most of the adhesive layer 221 remains on the base 210 when the substrate 100 is peeled from the substrate holder 200 using a laminate peeler or the like.

  FIG. 15 is a cross-sectional view showing a state in which the substrate holding portion is bonded to the ground main surface of the substrate in the present embodiment. As shown in FIG. 15, the substrate 100 is bonded to the substrate holding portion 200 so that the ground main surface 110 of the substrate 100 and the adhesive layer 220 are in contact with each other.

  FIG. 16 is a cross-sectional view showing a state in which a substrate whose one side is ground is fixed via a substrate holding part in the present embodiment. As shown in FIG. 16, the substrate holding unit 200 is placed on the vacuum suction plate 400 so that the base 210 of the substrate holding unit 200 to which the substrate 100 is bonded is in contact with the upper surface of the vacuum suction plate 400. Then, the vacuum pump 500 is operated. As the vacuum pump 500 is operated, the air in the hose 510 is sucked in the direction of the arrow 520. As a result, air is sucked and degassed from the substrate 210 side of the substrate holder 200 that is in contact with the upper surface of the vacuum suction plate 400. The substrate holder 200 is fixed by vacuum suction. As a result, the substrate 100 is fixed.

  With the substrate 100 fixed as described above, the other main surface 120 of the substrate 100 is ground. In the present embodiment, the surface roughness of one main surface 110 of the substrate 100 is reduced by grinding the grinding wheel 300 from the surface to a depth of several tens to several hundreds of μm while feeding the grinding wheel 300 in the direction of the hollow arrow in the figure. The thickness is about 0.5 μm to about several tens μm before grinding to about 0.1 μm to several μm. In the present embodiment, the metal grinding wheel 300 is used, but a vitrified grinding wheel may be used as the grinding wheel 300.

  FIG. 17 is a cross-sectional view showing a state in which vacuum suction is released after grinding of the other main surface of the substrate in the present embodiment. As shown in FIG. 17, after the grinding of the other main surface 120 of the substrate 100 is finished, the vacuum suction of the substrate holding part 200 is released by stopping the vacuum pump 500.

  FIG. 18 is a cross-sectional view showing a state in which ultraviolet rays are applied to the adhesive layer of the substrate holding unit that holds the substrate whose both surfaces are ground in this embodiment. As shown in FIG. 18, the adhesive layer 220 is cured to become the adhesive layer 221 by irradiating the adhesive layer 220 with ultraviolet rays 610 from the ultraviolet irradiation unit 600.

  The cured adhesive layer 221 has lost its viscosity. In the cured state, the adhesive layer 221 of the present embodiment has a stronger bonding force with the base material 210 than the bonding force with the substrate 100. Therefore, most of the adhesive layer 221 remains on the base 210 when the substrate 100 is peeled from the substrate holder 200 using a laminate peeler or the like.

  The substrate 100 whose both main surfaces are ground is annealed in order to relieve the processing stress distortion during grinding. FIG. 19 is a cross-sectional view showing a state in which the substrate is annealed in the present embodiment. As shown in FIG. 19, the residual stress in the substrate 100 a is removed by annealing in a high temperature furnace 700 at a temperature of several thousand hundred degrees C. for several hours to several tens of hours. By annealing, scale adheres to the surface of the substrate 100a. Therefore, the main surface on the side where the semiconductor device is formed is ground again to perform mirror finish.

  FIG. 20 is a cross-sectional view showing a state in which the annealed substrate is bonded to the substrate holding portion in the present embodiment. As shown in FIG. 20, the annealed substrate 100a is bonded to the substrate holding part 200 so that the main surface of the substrate 100a and the adhesive layer 220 are in contact with each other.

  FIG. 21 is a cross-sectional view showing a state where the annealed substrate is fixed via the substrate holding portion in the present embodiment. As shown in FIG. 21, the substrate holding unit 200 is placed on the vacuum suction plate 400 so that the base 210 of the substrate holding unit 200 to which the substrate 100a is bonded is in contact with the upper surface of the vacuum suction plate 400. Then, the vacuum pump 500 is operated. As the vacuum pump 500 is operated, the air in the hose 510 is sucked in the direction of the arrow 520. As a result, air is sucked and degassed from the substrate 210 side of the substrate holder 200 that is in contact with the upper surface of the vacuum suction plate 400. The substrate holder 200 is fixed by vacuum suction. As a result, the substrate 100a is fixed.

  With the substrate 100a fixed as described above, the substrate 100a is ground. In the present embodiment, the surface roughness of the main surface of the substrate 100 is reduced from 0.5 μm before grinding by grinding the grinding wheel 300 to a depth of several tens of μm from the surface while feeding the grinding wheel 300 in the direction of the hollow arrow in the figure. About a few dozen μm to 0.01 nm-0. Set to about several nm.

  FIG. 22 is a cross-sectional view showing a state in which vacuum suction is released after mirror finishing of the main surface of the substrate in the present embodiment. As shown in FIG. 22, after the grinding of the main surface of the substrate 100 a ′ is completed, the vacuum suction of the substrate holding unit 200 is released by stopping the vacuum pump 500.

  FIG. 23 is a cross-sectional view showing a state in which the adhesive layer of the substrate holding unit that holds the mirror-finished substrate is irradiated with ultraviolet rays in the present embodiment. As shown in FIG. 23, the adhesive layer 220 is cured to become an adhesive layer 221 by irradiating the adhesive layer 220 with ultraviolet rays 610 from the ultraviolet irradiation unit 600.

  The cured adhesive layer 221 has lost its viscosity. In the cured state, the adhesive layer 221 of the present embodiment has a stronger bonding force with the base material 210 than with the substrate 100a '. Therefore, most of the adhesive layer 221 remains on the base 210 when the substrate 100 a ′ is peeled from the substrate holding part 200 using a laminate peeler or the like.

  In the present embodiment, as described above, after grinding the substrate 100 bonded to the substrate holding part 200 having the adhesive layer 220 that is cured when irradiated with ultraviolet rays, the adhesive layer 220 is cured to form the substrate 100a ′. By peeling from the substrate holding part 200, it is possible to suppress the adhesion layer 221 from adhering to the ground substrate 100a ′. Therefore, it is possible to reduce the work of removing the adhesive layer 221 attached from the ground substrate 100a '. Therefore, the substrate 100 can be easily ground, and the manufacturing cost of a semiconductor element manufactured using the substrate 100a 'can be reduced.

  The thickness of the adhesive layer of the substrate holding part 200 is preferably 1 μm or more and 100 μm or less. In this case, it is possible to vacuum-suck the substrate holding part 200 in a state where the unevenness having a size of 10 tens μm or less of the substrate 100 before grinding is substantially filled with the adhesive layer 220, and Since the thickness is thin, the bonding force of the adhesive layer 220 can be stabilized. Furthermore, by reducing the thickness of the adhesive layer 220, the material necessary for manufacturing the substrate holding part 200 can be reduced, and the manufacturing cost of the substrate holding part 200 can be reduced.

  Hereinafter, an experimental example in which the surface roughness of the substrate ground by the grinding method of the first and second embodiments is confirmed will be described.

(Experimental example 1)
As the substrate 100, a sapphire substrate having a dimension of 4 inches and a thickness of 1.3 mm was prepared. As the substrate holding unit 800 in Embodiment 1, a sheet made of breathable polyurethane and having a thickness of 150 μm was prepared. As the substrate holding part 200 in the second embodiment, an ultraviolet curable adhesive layer 220 made of a resin containing an acrylic monomer and a photopolymerization initiator and having a thickness of 50 μm, and a polyethylene terephthalate resin having a thickness of 100 μm. A tape comprising a certain substrate 210 was prepared.

  The substrate 100 of the first and second embodiments was ground with a metal grinding wheel 300 of # 500 using a vacuum suction plate 400 made of porous ceramic. The processing speed was 0.02 mm / min to 0.08 mm / min, and 0.37 mm (0.185 mm per side) was ground on both surfaces of the substrate 100 of the first and second embodiments.

  After releasing the vacuum suction after the substrate grinding in the first embodiment and separating the substrate 100 and the sheet that is the substrate holding unit 800, the main surface of the substrate 100a was visually observed. No trace was confirmed.

After grinding the substrate in the second embodiment, the adhesive layer 221 was cured by irradiating the adhesive layer 220 with ultraviolet rays for 30 seconds at an ultraviolet illuminance of 300 mW / cm ² with an ultraviolet high pressure mercury lamp. Then, when the board | substrate 100a was peeled from the board | substrate holding | maintenance part 200 and the main surface of the board | substrate 100a was observed visually, the residue of the contact bonding layer 221 was not able to be confirmed.

  The substrates whose both surfaces were ground in Embodiments 1 and 2 were each annealed in a high temperature furnace at a temperature of 1300 ° C. for 10 hours. Each of the annealed substrates 100a was vacuum-fixed and polished by 0.028 mm with a # 1200 vitrified grindstone at a processing speed of 0.001 mm / min. Thereafter, the substrate 100a was polished to a 0.002 mm mirror finish with a polishing speed of 0.0002 mm / min.

  The polished surface of the substrate after mirror polishing in Embodiments 1 and 2 was confirmed with an atomic force microscope. FIG. 24 is an atomic force microscope photograph of the polished surface of the substrate ground by the grinding method of the first embodiment. FIG. 25 is an atomic force micrograph of the polished surface of the substrate ground by the grinding method of the second embodiment.

  As shown in FIGS. 24 and 25, the surface roughness of the polished surface of the substrate ground by the method of Embodiments 1 and 2 was 0.05 nm to 0.3 nm. This sufficiently satisfies the surface roughness necessary for producing the semiconductor structure. Therefore, it was confirmed that the substrate manufactured using the grinding methods of Embodiments 1 and 2 has sufficient performance for manufacturing a semiconductor element.

  In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It does not become a basis of limited interpretation. Therefore, the technical scope of the present invention is not interpreted only by the above-described embodiments, but is defined based on the description of the scope of claims. Further, all modifications within the meaning and scope equivalent to the scope of the claims are included.

  100, 100a, 100a ′ substrate, 110 one main surface, 120 other main surface, 200, 800 substrate holding part, 210 base material, 220, 221 adhesive layer, 300 grinding wheel, 400 vacuum suction plate, 500 vacuum pump, 510 hose, 600 UV irradiation unit, 610, LED UV, 700 high temperature furnace.

Claims (6)

Placing the substrate on one main surface of the plate-like substrate holding portion including the outer surface and the void communicating with the inside and having elasticity; and
By degassing from the other main surface side of the substrate holding portion, the substrate holding portion is deformed so that the one main surface of the substrate holding portion conforms to the surface shape of the substrate. Through vacuum suction and fixing,
Grinding the main surface of the substrate opposite to the main surface in contact with the substrate holding portion in a state where the substrate is fixed via the substrate holding portion;
And a step of releasing the vacuum suction after the step of grinding.   The substrate grinding method according to claim 1, wherein the thickness of the substrate holding part is 10 μm or more and 500 μm or less.   The substrate grinding method according to claim 1 or 2, wherein the shape of the one main surface of the substrate holding part is restored to the original shape by releasing the vacuum suction. Bonding the substrate holding portion having an adhesive layer that is cured by receiving ultraviolet rays on a flat substrate so that one main surface of the substrate is in contact with the adhesive layer;
Fixing the substrate holding part by vacuum-adsorbing the base material of the substrate holding part to which the substrate is bonded; and
Grinding the other main surface of the substrate in a state where the substrate holding portion is fixed;
After the step of grinding, releasing the vacuum suction of the substrate holding part;
After the step of releasing the vacuum suction, irradiating the adhesive layer of the substrate holding part with ultraviolet rays,
A substrate grinding method comprising: a step of peeling the substrate holding part and the substrate after the step of irradiating the ultraviolet rays.   The substrate grinding method according to claim 4, wherein the adhesive layer has a thickness of 1 μm to 100 μm.   A semiconductor device manufactured using the substrate grinding method according to claim 1.