Method for manufacturing laminated board in which a plurality of substrates are bonded

Abstract

The present invention pertains to a method for manufacturing a laminated board by bonding a plurality of substrates (e.g., wafers). This method for manufacturing a laminated board (Ws) includes: forming a step part on a peripheral edge part of a first substrate (W1) by a trimming device; filling the step part with a filler (5) by a filling device; removing a part of the filler (5) by a flattening device until an exposed surface of the filler (5) is coplanar with as a first surface (1a) of the first substrate (W1); bonding the first surface (1a) of the first substrate (W1), from which the part of the filler (5) has been removed, to a second substrate (W2); and grinding a second surface (1b) of the first substrate (W1) opposite to the first surface (1a) by a thinning device.

Description

Method for producing a laminated substrate in which multiple substrates are bonded

[0001] The present invention relates to a method for bonding multiple substrates (e.g., wafers) together to create a laminated substrate.

[0002] In recent years, in order to achieve even higher density and higher functionality in semiconductor devices, development of three-dimensional packaging technology, which stacks multiple substrates to integrate them three-dimensionally, has progressed. In three-dimensional packaging technology, for example, the device surface of a first substrate on which integrated circuits and electrical wiring are formed is bonded to the device surface of a second substrate on which integrated circuits and electrical wiring are formed. Furthermore, after bonding the first substrate to the second substrate, the first substrate is thinned using a polishing or grinding device. In this way, integrated circuits can be stacked in a direction perpendicular to the device surfaces of the first and second substrates.

[0003] JP 2022-38834 A

[0004] Typically, the edge of a substrate is pre-polished to a rounded or chamfered shape to prevent cracking or chipping. Grinding a first substrate having such a shape results in the formation of a sharp edge on the first substrate. This sharp edge (hereinafter referred to as a knife edge) is formed by the back surface of the ground first substrate and the outer peripheral surface of the first substrate. Such a knife edge is easily chipped by physical contact, which can cause damage to the laminated substrate itself during transportation.

[0005] Therefore, the present invention provides a method for producing a laminated substrate that can prevent cracks and chips from occurring in a laminated substrate formed by bonding a plurality of substrates.

[0006] In one aspect, a method for producing a laminated substrate is provided, the method including: forming a step portion on a peripheral edge portion of a first substrate using a trimming device; filling the step portion with a filler material using a filling device; removing a portion of the filler material using a planarizing device until an exposed surface of the filler material is positioned in the same plane as a first surface of the first substrate; bonding the first surface of the first substrate from which the portion of the filler material has been removed to a second substrate; and grinding a second surface of the first substrate opposite the first surface using a thinning device.

[0007] In one aspect, the filler is any one of an oxidizing material, a resin, and a metal. In one aspect, the filler is an oxidizing material. In one aspect, the filler is filled into the step portion until it rises from the first surface. In one aspect, the method for producing a laminated substrate further includes forming a step portion at the peripheral edge of the second substrate using a trimming device, filling the step portion of the second substrate with the filler using a filling device, and removing a portion of the filler on the second substrate using a planarizing device until the exposed surface of the filler on the second substrate is positioned in the same plane as the first surface of the second substrate.

[0008] The filler can support the knife edge formed after the thinning process of the first substrate. Therefore, the filler can prevent cracking and chipping of the laminated substrate. In particular, since the filler is filled into the step portion before the first substrate is bonded to the second substrate, the filler can be filled into the entire step portion, including the inner corners, without voids.

[0009] 7 is a schematic diagram showing an embodiment of a method for producing a laminated substrate; FIG. 8 is a side view showing an embodiment of a trimming device that performs a trimming process; FIG. 9 is a schematic diagram of the trimming device shown in FIG. 2 as viewed from the direction indicated by arrow A; FIG. 10 is a side view showing an embodiment of a filling device that performs a filling process; FIG. 11 is a schematic diagram of an embodiment of a spray nozzle; FIG. 12 is a schematic diagram of another embodiment of a filling device that performs a filling process; FIG. 13 is a side view showing an embodiment of a planarizing device that performs a planarizing process; FIG. 14 is a schematic diagram of the planarizing device shown in FIG. 7 as viewed from the direction indicated by arrow B; FIG. 15 is a perspective view showing another embodiment of a planarizing device that performs a planarizing process; FIG. 16 is a schematic diagram of yet another embodiment of a planarizing device; FIG. 17 is a schematic diagram of an embodiment of a thinning device that performs a thinning process.

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic diagram showing one embodiment of a method for producing a laminated substrate. As shown in Fig. 1, first, a first substrate W1 is prepared. The first substrate W1 is a wafer having devices formed on a first surface 1a, or a silicon wafer having a first surface 1a on which no devices are formed.

[0011] Next, a trimming step is performed to form a step 3 on the peripheral edge of the first substrate W1. The step 3 has an annular shape extending in the circumferential direction of the first substrate W1. The step 3 has an inner corner 4. In one embodiment, the inner corner 4 has a right-angled shape. In one embodiment, the radial width of the step 3 is within a range of 5 mm to 10 mm. The trimming step is performed by a trimming device described below.

[0012] After the step 3 is formed, a filling step is performed in which the step 3 is filled with the filler 5. The filler 5 is filled into the step 3 until it protrudes from the first surface 1a. In one embodiment, the filler 5 protrudes from the first surface 1a to a height of 1 nm to 20 μm. The filler 5 may protrude slightly from the step 3. For example, a portion of the filler 5 may be deposited on the first surface 1a.

[0013] In one embodiment, the filler 5 has heat resistance such that it does not soften even at a high temperature of about 250° C. Examples of the filler 5 include an oxidizing material, a resin, and a metal. Examples of the oxidizing material include silicon dioxide (SiO ２ ), silicon nitride (SiN), and carbon-containing silicon oxide (SiOC). Examples of resins include benzocyclobutene (BCB) resin and SOG (Spin-on-glass). The resin is appropriately adjusted so that it has heat resistance that does not soften even at high temperatures of about 250°C. Examples of metals include copper (Cu), tantalum (Ta), titanium (Ti), and metal alkoxides.

[0014] In the embodiment described below, an oxidizing material is used for the filler 5. More specifically, silicon dioxide (SiO ２ ) is used as the filler 5. Silicon dioxide (SiO ２ Oxidizing materials such as silicon dioxide (SiO ) have excellent heat resistance and electrical insulation properties. ２ ) can withstand temperatures higher than those required in the bonding step of the first substrate W1 and the second substrate W2, which will be described later. The filling step is carried out by a filling device, which will be described later.

[0015] Next, a planarization step is performed in which part of the filler 5 is removed until the exposed surface of the filler 5 is positioned in the same plane as the first surface 1 a of the first substrate W1. That is, the raised part of the filler 5 is removed, and the height of the exposed surface of the filler 5 becomes the same height as the first surface 1 a of the first substrate W1. The planarization step is performed by a planarization apparatus described below.

[0016] Next, a bonding process is performed in which the first surface 1a of the first substrate W1, from which part of the filler 5 has been removed, is bonded to a second substrate W2. The second substrate W2 may be prepared in advance, or may be prepared after the planarization process of the first substrate W1 is completed, or may be prepared simultaneously with the first substrate W1. In this embodiment, the second substrate W2 has the same configuration as the first substrate W1. In other embodiments, the second substrate W2 may have a different configuration from the first substrate W1.

[0017] In one embodiment, the second substrate W2 is prepared in the same manner as the first substrate W1, i.e., a step 7 is formed on the peripheral edge of the second substrate W2, the filler 8 is filled into the step 7 of the second substrate W2 until the filler 8 rises above the first surface 2 a of the second substrate W2, and part of the filler 8 on the second substrate W2 is removed until the exposed surface of the filler 8 on the second substrate W2 is flush with the first surface 2 a of the second substrate W2.

[0018] A first surface 1a of the first substrate W1 is bonded to a first surface 2a of the second substrate W2. The filler 5 of the first substrate W1 faces and contacts the filler 8 of the second substrate W2. Bonding of the first substrate W1 and the second substrate W2 is performed using known techniques such as hybrid bonding or fusion bonding.

[0019] Next, a thinning process is performed in which a second surface 1b of the first substrate W1 opposite to the first surface 1a is ground. In this thinning process, the thickness of the first substrate W1 is reduced. The thinning process is completed before the filler 5 on the first substrate W1 is ground. In other words, the filler 5 on the first substrate W1 is not ground in the thinning process. The thinning process is performed by a thinning apparatus described below.

[0020] In this way, through the trimming process, filling process, flattening process, bonding process, and thinning process, a laminated substrate Ws is completed, which has the first substrate W1, the second substrate W2, and the fillers 5, 8 filled in the step portions 3, 7.

[0021] The filler 5 can support the knife edge portion formed after the thinning process of the first substrate W1. Therefore, the filler 5 can prevent cracking and chipping of the laminated substrate Ws. In particular, since the filler 5 is filled into the step portion 3 of the first substrate W1 before the first substrate W1 is bonded to the second substrate W2, the filler 5 can fill the entire step portion 3, including the inner corner portion 4, without leaving voids (gaps).

[0022] Fig. 2 is a side view showing one embodiment of a trimming apparatus for performing a trimming step, and Fig. 3 is a schematic view of the trimming apparatus shown in Fig. 2 as viewed from the direction indicated by arrow A. The trimming apparatus of this embodiment is a polishing apparatus that forms a step 3 on the peripheral edge of the first substrate W1 by pressing a polishing tape 11 against the peripheral edge of the first substrate W1 while rotating the first substrate W1. The trimming apparatus includes a substrate holder 12 that holds and rotates the first substrate W1, a pressing member 15 that presses the polishing tape 11 against the peripheral edge of the first substrate W1, a pressing actuator 16 that applies a pressing force to the pressing member 15, a tape unwinding reel 18 that supplies the polishing tape 11 to the pressing member 15, and a tape take-up reel 19 that recovers the polishing tape 11 supplied to the pressing member 15.

[0023] The substrate holder 12 includes a holding stage 20 that holds the first substrate W1, and a stage rotation mechanism 21 that rotates the holding stage 20 together with the first substrate W1. The holding stage 20 is configured to hold the first substrate W1 by vacuum suction. The stage rotation mechanism 21 includes an electric motor (not shown).

[0024] The pressing member 15 is disposed above the holding stage 20. The pressing member 15 is made of hard resin or metal. The pressing actuator 16 is connected to the pressing member 15 and configured to move the pressing member 15 in directions toward and away from the peripheral edge of the first substrate W1 on the holding stage 20. There are no particular limitations on the specific configuration of the pressing actuator 16, but the pressing actuator 16 is configured from an air cylinder or an electric linear actuator.

[0025] The step 3 of the first substrate W1 is formed as follows. The first substrate W1 is held on the holding stage 20 with its first surface 1a facing upward. The stage rotation mechanism 21 rotates the first substrate W1 and the holding stage 20 as indicated by the arrow. While the polishing tape 11 is fed at a predetermined speed from the tape supply reel 18 to the tape take-up reel 19 via the pressing member 15, the pressing actuator 16 presses the pressing member 15 toward the first substrate W1, and the pressing member 15 presses the polishing tape 11 against the peripheral edge of the first substrate W1. The polishing tape 11 polishes the peripheral edge of the first substrate W1, resulting in the formation of the step 3 on the peripheral edge of the first substrate W1, as shown in the trimming process of FIG. 1 .

[0026] The trimming device is not limited to the polishing device using the polishing tape 11 shown in Figures 2 and 3. In other embodiments, the trimming device may be a laser processing device that forms a step 3 on the peripheral edge of the first substrate W1 using a laser beam. In still other embodiments, the step 3 may be formed by pressing a grindstone, instead of the polishing tape 11, against the peripheral edge of the first substrate W1.

[0027] The trimming device described above can be used to form the step 7 on the peripheral edge of the second substrate W2. Other types of trimming device may also be used to form the step 7 on the peripheral edge of the second substrate W2.

[0028] 4 is a side view showing an embodiment of a filling device for performing the filling step. The filling device includes a substrate holder 27 that holds and rotates the first substrate W1, and an injection nozzle 30 that injects particles of filler 5 onto a step 3 formed on the peripheral edge of the first substrate W1.

[0029] The substrate holder 27 includes a holding stage 32 that holds the first substrate W1, and a stage rotation mechanism 33 that rotates the holding stage 32. The holding stage 32 is configured to hold the first substrate W1 by vacuum suction. The stage rotation mechanism 33 includes an electric motor (not shown). The stage rotation mechanism 33 is configured to rotate the holding stage 32 and the first substrate W1 together.

[0030] In one embodiment, the substrate holding unit 27 may be provided with a plurality of (e.g., four) rollers (not shown) that can contact the peripheral edge of the first substrate W1, instead of the holding stage 32, and the first substrate W1 may be held by these rollers. In this case, the substrate holding unit 27 is provided with a roller rotation mechanism (not shown) that rotates each roller around its axis at the same speed in the same direction, instead of the stage rotation mechanism 33. By rotating the plurality of rollers with the roller rotation mechanism, the first substrate W1 is rotated around the rotation center of the substrate holding unit 27.

[0031] The filling device includes a filler supply line 35 for supplying particles of the filler 5 to the injection nozzle 30. The filler supply line 35 is connected to the injection nozzle 30. The injection nozzle 30 is connected to a filler supply source 36 via the filler supply line 35. The filler 5 is a powder that does not contain a volatile component such as a solvent. In one embodiment, the particle size (diameter) of the filler 5 is in the range of 1 μm to 100 μm, and more preferably, the particle size (diameter) of the filler 5 is in the range of 1 μm to 10 μm. An example of the filler supply source 36 is a disk-type powder feeder. In one embodiment, the filler 5 is silicon dioxide (SiO ２ ) powder.

[0032] The filler material supply source 36 is connected to a carrier gas supply source 39 via a carrier gas supply line 38. When a carrier gas is supplied from the carrier gas supply source 39 to the filler material supply source 36 through the carrier gas supply line 38, the filler material 5 in the filler material supply source 36 flows into the filler material supply line 35 together with the carrier gas. The filler material 5 is supplied to the injection nozzle 30 through the filler material supply line 35 together with the carrier gas. Examples of the carrier gas include gases such as nitrogen, air, helium, and argon, or a mixture thereof.

[0033] The injection nozzle 30 is located above a step 3 formed on the periphery of the first substrate W1 held by the substrate holding part 27, and is disposed above the first substrate W1 so as to face the step 3 of the first substrate W1. The injection nozzle 30 is configured to accelerate the filler 5 and inject the filler 5 onto the step 3 of the first substrate W1. The injection nozzle 30 is configured to cause the accelerated filler 5 to collide with the step 3 of the first substrate W1, thereby depositing the filler 5 on the step 3 of the first substrate W1. The injection nozzle 30 injects the filler 5 from the injection nozzle 30 while rotating the first substrate W1 by the substrate holding part 27. This makes it possible to fill the entire annular step 3 of the first substrate W1 with the filler 5.

[0034] FIG. 5 is a schematic diagram showing one embodiment of the injection nozzle 30. The injection nozzle 30 of this embodiment is a Laval nozzle. In the following description, the injection nozzle 30 may be referred to as a Laval nozzle 30. The Laval nozzle 30 is configured to accelerate the filler material 5 to the speed of sound or faster. The Laval nozzle 30 includes a nozzle body 40 having a diameter-reduced portion 40a in which the diameter is locally reduced, and a flow path 41 formed by the inner surface of the nozzle body 40. The flow path 41 communicates with the filler supply line 35. The flow path 41 is formed by the diameter-reduced portion 40a and has a throat portion 41a in which the horizontal cross-sectional area of ​​the nozzle body 40 is minimized. The nozzle body 40 has an injection port 40b at its tip for ejecting the filler material 5.

[0035] The carrier gas and filler material 5 supplied to the Laval nozzle 30 through the filler material supply line 35 flow through the flow path 41. The carrier gas is compressed in the throat 41a of the flow path 41. In the flow direction of the carrier gas and the filler material 5, the carrier gas expands downstream of the throat 41a, causing the flow velocities of the carrier gas and the filler material 5 to reach or exceed the speed of sound (sonic or supersonic). The filler material 5 accelerated to or exceeding the speed of sound is sprayed from the Laval nozzle 30 through the spray port 40b.

[0036] The Laval nozzle 30 of this embodiment is connected to a heated gas supply line 45 for supplying heated gas to the Laval nozzle 30. The heated gas supply line 45 is connected to a heater 46. The heater 46 is configured to heat the carrier gas supplied from the carrier gas supply source 39 through a carrier gas supply line 47. In one embodiment, the temperature of the carrier gas heated by the heater 46 (i.e., the heated gas) is in the range of 100°C to 2000°C.

[0037] The carrier gas (hereinafter referred to as the heated gas) heated by the heater 46 is supplied to the Laval nozzle 30 through the heated gas supply line 45. The Laval nozzle 30 further includes a heated gas inlet port 43 connected to the heated gas supply line 45. In this embodiment, the heated gas inlet port 43 is connected to the nozzle body 40 upstream of the diameter contraction section 40a in the flow direction of the carrier gas and the filler 5, and is connected to the flow path 41. The heated gas supplied to the flow path 41 heats the filler 5 flowing through the flow path 41 by its heat. The heated filler 5 is accelerated in the flow path 41 to a speed greater than the speed of sound and is sprayed from the Laval nozzle 30 through the spray port 40b. Particles of the filler 5 are deformed upon collision with the step 3 of the first substrate W1, cooled by the step 3 of the first substrate W1, and deposited on the step 3 of the first substrate W1. As a result, the step portion 3 of the first substrate W1 is filled with the filling material 5.

[0038] In one embodiment, when the speed of the filler 5 sprayed from the Laval nozzle 30 is sufficiently high (for example, when the speed of the filler 5 is 500 m / sec or more), the Laval nozzle 30 does not need to be provided with the heated gas introduction port 43, and heated gas does not need to be supplied into the Laval nozzle 30. This is because, when the speed of the filler 5 sprayed from the Laval nozzle 30 is sufficiently high, the filler 5 is heated and deformed upon collision with the step portion 3 of the first substrate W1, even if it is not softened, and the filler 5 can be deposited on the step portion 3 of the first substrate W1.

[0039] 5 is a Laval nozzle, the spray nozzle 30 is not limited to a Laval nozzle as long as the spray nozzle 30 can locally fill the step portion 3 of the first substrate W1 with the filler material 5. In one embodiment, the spray nozzle 30 may be a plasma spray nozzle or a flame spray nozzle.

[0040] 6 is a schematic diagram showing another embodiment of the filling apparatus. The embodiment of the filling apparatus shown in FIG. 6 is a PVD or CVD apparatus having a processing chamber 51, a substrate stage 52 disposed within the processing chamber 51, and a filling material supply source (not shown). The configuration of the filling material supply source varies depending on the PVD or CVD apparatus. The PVD or CVD apparatus used in the filling apparatus is a known apparatus, and therefore a detailed description thereof will be omitted.

[0041] The first surface 1a of the first substrate W1 is covered with a protective film 55 (e.g., resist) so that only the step portion 3 is exposed. The first substrate W1 is then supported on the substrate stage 52 with its first surface 1a facing upward. With the first surface 1a covered with the protective film 55, a filler 5 is deposited on the step portion 3 of the first substrate W1, and the step portion 3 is filled with the filler 5. After the step portion 3 is filled with the filler 5, the first substrate W1 is removed from the processing chamber 51. Furthermore, the protective film 55 is removed from the first substrate W1. As a result, the filler 5 is obtained, filling the step portion 3 to the extent that it rises above the first surface 1a.

[0042] Although the embodiment of the filling device has been described with reference to Figures 4 to 6, the filling device is not limited to the above embodiment as long as it is capable of locally filling the step portion 3 of the first substrate W1 with the filler material 5.

[0043] Fig. 7 is a side view showing one embodiment of a planarization apparatus that performs the planarization step, and Fig. 8 is a schematic view of the planarization apparatus shown in Fig. 7 as seen from the direction indicated by arrow B. The planarization apparatus of this embodiment is a polishing apparatus that removes part of the filler 5 by pressing a polishing tape 60 against the filler 5 on the step portion 3 of the first substrate W1 while rotating the first substrate W1.

[0044] The planarization device includes a substrate holding unit 61 that holds and rotates the first substrate W1, a pressing member 63 that presses the polishing tape 60 against the peripheral edge of the first substrate W1, a pressing actuator 65 that applies a pressing force to the pressing member 63, a tape unwinding reel 67 that supplies the polishing tape 60 to the pressing member 63, and a tape winding reel 68 that recovers the polishing tape 60 supplied to the pressing member 63.

[0045] The substrate holder 61 includes a holding stage 70 that holds the first substrate W1, and a stage rotation mechanism 71 that rotates the holding stage 70 together with the first substrate W1. The holding stage 70 is configured to hold the first substrate W1 by vacuum suction. The stage rotation mechanism 71 includes an electric motor (not shown).

[0046] The pressing member 63 is disposed above the holding stage 70. The pressing member 63 is made of hard resin or metal. As shown in FIG. 8 , the width of the pressing member 63 is greater than the width of the step portion 3 of the first substrate W1. The pressing actuator 65 is connected to the pressing member 63, and is configured to move the pressing member 63 toward and away from the peripheral edge of the first substrate W1 on the holding stage 70. The specific configuration of the pressing actuator 65 is not particularly limited, but the pressing actuator 65 is configured from an air cylinder or an electric linear actuator.

[0047] The planarization of the filler 5 on the first substrate W1 is formed as follows. The first substrate W1 is held by a holding stage 70 with its first surface 1a facing upward. A stage rotation mechanism 71 rotates the first substrate W1 and the holding stage 70 as indicated by the arrow. While the polishing tape 60 is fed at a predetermined speed from a tape supply reel 67 to a tape take-up reel 68 via a pressing member 63, a pressing actuator 65 presses the pressing member 63 toward the first substrate W1, and the pressing member 63 presses the polishing tape 60 against the filler 5 formed on the step portion 3 of the first substrate W1. The polishing tape 60 removes a portion of the filler 5.

[0048] 8, the pressing member 63 presses the polishing tape 60 against the filler 5 until the surface of the filler 5 is positioned in the same plane as the first surface 1a of the first substrate W1. As a result, as shown in the planarization process in FIG. 1, the height of the exposed surface of the filler 5 becomes the same as the height of the first surface 1a of the first substrate W1.

[0049] 9 is a perspective view showing another embodiment of a planarization apparatus for performing a planarization step. The planarization apparatus of this embodiment is a chemical mechanical polishing (CMP) apparatus that removes part of the filler 5 deposited on the step portion 3 of the first substrate W1 by pressing the filler 5 against the polishing surface of the polishing pad 76 while supplying a polishing liquid such as slurry onto a polishing pad 76 supported on a polishing table 75.

[0050] 9, the planarization apparatus configured from a polishing device includes a polishing table 75 that supports a polishing pad 76, a polishing head 77 that presses the first substrate W1 against the polishing pad 76, a table motor 80 that rotates the polishing table 75, and a polishing liquid supply nozzle 83 for supplying a polishing liquid such as slurry onto the polishing pad 76. The upper surface of the polishing pad 76 forms a polishing surface 76a for removing a portion of the filler 5 on the first substrate W1.

[0051] The polishing head 77 is connected to a head shaft 78, and the head shaft 78 is connected to a polishing head rotating device 79. The polishing head rotating device 79 is configured to rotate the polishing head 77 together with the head shaft 78 in the direction indicated by the arrow. The configuration of the polishing head rotating device 79 is not particularly limited, but in one example, the polishing head rotating device 79 includes an electric motor, a belt, a pulley, etc. The polishing table 75 is connected to a table motor 80, and the table motor 80 is configured to rotate the polishing table 75 and the polishing pad 76 in the direction indicated by the arrow.

[0052] Removal of a portion of the filler 5 on the first substrate W1 using the planarization apparatus shown in Figure 9 is performed as follows. The first substrate W1 is held by the polishing head 77 with its first surface 1a facing downward. A table motor 80 and a polishing head rotation device 79 rotate the polishing table 75 and the polishing head 77 in the directions indicated by the arrows in Figure 9, while a polishing liquid is supplied from a polishing liquid supply nozzle 83 to the polishing surface 76a of the polishing pad 76 on the polishing table 75. While the first substrate W1 is rotated by the polishing head 77, the filler 5 on the first substrate W1 is pressed against the polishing surface 76a of the polishing pad 76 by the polishing head 77, with the polishing liquid present on the polishing pad 76. The filler 5 deposited on the step portion 3 of the first substrate W1 is polished by the chemical action of the polishing liquid and the mechanical action of the abrasive grains contained in the polishing liquid and / or the polishing pad 76, thereby removing a portion of the filler 5.

[0053] The filler 5 on the first substrate W1 is pressed against the polishing surface 76a of the polishing pad 76 until the surface of the filler 5 is positioned in the same plane as the first surface 1a of the first substrate W1. As a result, as shown in the planarization process in FIG. 1 , the height of the exposed surface of the filler 5 becomes the same as the height of the first surface 1a of the first substrate W1.

[0054] 10 is a schematic diagram showing yet another embodiment of the planarization apparatus. The planarization apparatus of this embodiment is a laser processing apparatus that uses laser light to remove part of the filler material 5 deposited on the step portion 3 of the first substrate W1.

[0055] As shown in FIG. 10 , the apparatus includes a substrate holder 85 that holds and rotates the first substrate W1, and a laser 86 that emits laser light toward the filler 5 on the step portion 3 of the first substrate W1 held by the substrate holder 85. The substrate holder 85 includes a holding stage 87 that holds the first substrate W1, and a stage rotation mechanism 88 that rotates the holding stage 87 together with the first substrate W1. The holding stage 87 is configured to hold the first substrate W1 by vacuum suction. The stage rotation mechanism 88 includes an electric motor (not shown). The laser 86 is disposed radially outward of the holding stage 87. The laser 86 is configured to emit laser light parallel to a substrate holding surface 87 a of the holding stage 87 (i.e., parallel to the first surface 1 a of the first substrate W1).

[0056] Removal of a portion of the filler 5 on the first substrate W1 using a planarization device composed of the laser processing apparatus shown in Figure 10 is performed as follows. While the substrate holder 85 rotates the first substrate W1, the laser 86 irradiates laser light onto the filler 5 deposited on the step portion 3 of the first substrate W1. The portion of the filler 5 protruding from the first surface 1a of the first substrate W1 is removed by the laser light. Removal of the filler 5 by the laser light is continued until the surface of the filler 5 is positioned in the same plane as the first surface 1a of the first substrate W1. As a result, as shown in the planarization process of Figure 1, the height of the exposed surface of the filler 5 becomes the same as the height of the first surface 1a of the first substrate W1.

[0057] 7 to 10, the planarization apparatus is not limited to the above-described embodiments as long as it can remove a portion of the filler 5 until the exposed surface of the filler 5 is flush with the first surface 1a of the first substrate W1. For example, instead of the polishing tape 60 shown in FIGS. 7 and 8, a grindstone or a polishing pad may be pressed against the filler 5 to remove a portion of the filler 5.

[0058] The second substrate W2 shown in Figure 1 is produced in the same manner as the first substrate W1. The trimming apparatus embodiments described with reference to Figures 2 and 3, the filling apparatus embodiments described with reference to Figures 4 to 6, and the planarizing apparatus embodiments described with reference to Figures 7 to 10 can be applied to the trimming process, filling process, and planarizing process for the second substrate W2.

[0059] 1, a first substrate W1 having a filler 5 formed thereon and located in the same plane as the first surface 1a is bonded to a second substrate W2 having a filler 8 formed thereon and located in the same plane as the first surface 2a. The bonding of the first substrate W1 and the second substrate W2 is performed using a known technique such as hybrid bonding or fusion bonding, and therefore a detailed description thereof will be omitted.

[0060] 11 is a schematic diagram showing one embodiment of a thinning apparatus for performing a thinning step. The thinning apparatus of this embodiment is a grinding apparatus that grinds the second surface 1b of the first substrate W1, which is opposite to the first surface 1a, using a grinding tool 90. As shown in FIG. 11 , the thinning apparatus including the grinding device includes a holding stage 91 that holds the second surface 2b of the second substrate W2, a grinding tool 90 that grinds the second surface 1b of the first substrate W1 bonded to the second substrate W2, a grinding tool rotation mechanism 93 that rotates the grinding tool 90, and a pressing actuator 94 that presses the grinding tool 90 against the second surface 1b of the first substrate W1.

[0061] An example of the grinding tool 90 is a grinding wheel. The pressing actuator 94 is connected to the grinding tool rotating mechanism 93 and configured to move the grinding tool rotating mechanism 93 and the grinding tool 90 together toward the first substrate W1. The grinding tool rotating mechanism 93 includes an electric motor (not shown). The specific configuration of the pressing actuator 94 is not particularly limited, but the pressing actuator 94 is configured from an air cylinder or an electric linear actuator.

[0062] Thinning of the first substrate W1 using the thinning apparatus including the grinding device shown in FIG. 11 is performed as follows. The second substrate W2 bonded to the first substrate W1 is held on a holding stage 91 with the first surface 1a of the first substrate W1 facing upward. While the grinding tool rotation mechanism 93 rotates the grinding tool 90, a pressure actuator 94 presses the grinding tool 90 against the first surface 1a of the first substrate W1. The first surface 1a of the first substrate W1 is gradually removed by the rotating grinding tool 90. Grinding of the first substrate W1 (the thinning process of the first substrate W1) is stopped before the grinding tool 90 reaches the filler 5 on the first substrate W1. As a result, a laminated substrate Ws as shown in the thinning process of FIG. 1 is produced.

[0063] Although the embodiment of the thinning apparatus has been described with reference to Figure 11, the thinning apparatus is not limited to the above embodiment as long as it is capable of thinning the first substrate W1. In one embodiment, the thinning apparatus may be a chemical mechanical polishing (CMP) apparatus.

[0064] The above-described embodiments have been described for the purpose of enabling a person of ordinary skill in the art to practice the present invention. Various modifications of the above-described embodiments would be obvious to a person skilled in the art, and the technical concept of the present invention may be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is to be interpreted in the broadest scope in accordance with the technical concept defined by the claims.

[0065] The present invention can be used in a method for bonding a plurality of substrates (for example, wafers) together to form a laminated substrate.

[0066] W1 First substrate 1a First surface 1b Second surface W2 Second substrate 2a First surface 2b Second surface 3, 7 Step portion 4 Inner corner portion 5, 8 Filler material Ws Laminated substrate 11 Polishing tape 12 Substrate holding portion 15 Pressing member 16 Pressing actuator 18 Tape supply reel 19 Tape take-up reel 20 Holding stage 21 Stage rotation mechanism 27 Substrate holding portion 30 Injection nozzle 32 Holding stage 33 Stage rotation mechanism 35 Filler material supply line 36 Filler material supply source 38 Carrier gas supply line 39 Carrier gas supply source 40 Nozzle body 40a Diameter reduction portion 40b Injection port 41 Flow path 41a Throat portion 43 Heated gas introduction port 45 Heated gas supply line 46 Heater 47 Carrier gas supply line 51 Processing chamber 52 Substrate stage 55 Protective film 60 Polishing tape 61 Substrate holder 63 Pressing member 65 Pressing actuator 67 Tape supply reel 68 Tape take-up reel 70 Holding stage 71 Stage rotation mechanism 75 Polishing table 76 Polishing pad 76a Polishing surface 77 Polishing head 78 Head shaft 79 Polishing head rotation device 80 Table motor 83 Polishing liquid supply nozzle 85 Substrate holder 86 Laser 87 Holding stage 88 Stage rotation mechanism 90 Grinding tool 91 Holding stage 93 Grinding tool rotation mechanism 94 Pressing actuator

Claims

1. A method for producing a laminated substrate, comprising: forming a step portion on the peripheral edge of a first substrate using a trimming device; filling the step portion with a filler using a filling device; removing a portion of the filler using a planarizing device until the exposed surface of the filler is positioned in the same plane as a first surface of the first substrate; bonding the first surface of the first substrate from which the portion of the filler has been removed to a second substrate; and grinding a second surface of the first substrate opposite the first surface using a thinning device.

2. The method for producing a laminated substrate according to claim 1, wherein the filler is any one of an oxide material, a resin, and a metal.

3. The method for producing a laminated substrate according to claim 2, wherein the filler is an oxidizing material.

4. The method for producing a laminated substrate according to claim 1, wherein the filler is filled into the step portion until it rises above the first surface.

5. The method for producing a laminated substrate according to claim 1, further comprising: forming a step portion on the peripheral edge of the second substrate using a trimming device; filling the step portion of the second substrate with a filler material using a filling device; and removing a portion of the filler material on the second substrate using a planarizing device until the exposed surface of the filler material on the second substrate is positioned in the same plane as the first surface of the second substrate.

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