Substrate bonding apparatus and substrate bonding method using the same

Abstract

A substrate bonding apparatus and a substrate bonding method are disclosed. The substrate bonding apparatus includes: a lower chuck for receiving a lower substrate; and an upper chuck disposed above the lower chuck. The upper substrate is fixed to the upper chuck. The upper and lower chucks bond the upper substrate to the lower substrate. The upper chuck has an upwardly convex surface facing the lower chuck. The upwardly convex surface includes a plurality of first ridges and a plurality of first valleys alternately arranged along an azimuth direction.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2018-0113155, filed on September 20, 2018, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] Exemplary embodiments of the present invention relate to an apparatus and a method for manufacturing a semiconductor device, and more specifically, to a substrate bonding apparatus and a substrate bonding method using the substrate bonding apparatus. Background Technology

[0004] With recent advancements in semiconductor devices, stacked semiconductor devices and stacked sensors have been proposed as alternatives to effectively reduce the physical size of electronic devices. In stacked semiconductor devices and sensors, logic cells, memory cells, processing circuitry, and complementary metal-oxide-semiconductor (CMOS) image sensors can be fabricated individually on multiple substrates. Multiple substrates can be bonded together to reduce the form factor of the stacked semiconductor devices and sensors. Summary of the Invention

[0005] An exemplary embodiment of the present invention provides a substrate bonding apparatus and a substrate bonding method using the substrate bonding apparatus, wherein deformation defects occurring on the substrate are prevented and reduced.

[0006] According to an exemplary embodiment of the present invention, a substrate bonding apparatus includes: a lower chuck for receiving a lower substrate; and an upper chuck disposed above the lower chuck. The upper substrate is fixed to the upper chuck. The upper and lower chucks bond the upper and lower substrates. The upper chuck has an upwardly convex surface facing the lower chuck. The upwardly convex surface includes a plurality of first ridges and a plurality of first valleys alternately arranged along an azimuth direction.

[0007] According to an exemplary embodiment of the present invention, a substrate bonding apparatus includes: a lower chuck for loading a lower substrate, and an upper chuck disposed above the lower chuck. The upper substrate is fixed to the upper chuck. The upper and lower chucks bond the upper substrate to the lower substrate. The upper chuck has an upwardly convex surface facing the lower chuck, and the upwardly convex surface is not flat along the azimuth direction.

[0008] According to an exemplary embodiment of the present invention, a substrate bonding method includes the steps of: fixing an upper substrate to an upper chuck; and bonding the upper substrate to a lower substrate. The lower substrate is disposed on a lower chuck, the lower chuck facing the upper chuck. The step of bonding the upper substrate to the lower substrate includes: bonding the center of the upper substrate to the center of the lower substrate; and bonding the edge of the upper substrate to the edge of the lower substrate. The step of bonding the edge of the upper substrate to the edge of the lower substrate includes: bonding a plurality of first ridges of the upper substrate to a plurality of second ridges of the lower substrate; and bonding a plurality of first valleys disposed between the first ridges to a plurality of second valleys disposed between the second ridges. Attached Figure Description

[0009] The above and other features of the present invention will become more apparent from the detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings, in which:

[0010] Figure 1 A plan view of a substrate bonding apparatus 100 showing an exemplary embodiment of the present invention is shown.

[0011] Figure 2 It shows along Figure 1 Cross-sectional views taken from lines I-I' and II-II'.

[0012] Figure 3 A plan view showing the chuck according to the comparison example is shown.

[0013] Figure 4 The display shows along Figure 1 and Figure 2 The image shows a cross-sectional view of the upper substrate taken from the edge of the upper substrate.

[0014] Figure 5 The display shows along Figure 1 and Figure 2 The image shows a cross-sectional view of the lower substrate taken from the edge of the lower substrate.

[0015] Figure 6 The diagram shows the display along each direction. Figure 1 Cross-sectional views of the upper and lower chucks as shown by lines I-I' and II-II'.

[0016] Figure 7 A flowchart illustrating a substrate bonding method according to an exemplary embodiment of the present invention is shown.

[0017] Figure 8 The display shows Figure 7 The flowchart shows an example of a substrate bonding operation.

[0018] Figure 9 and Figure 10It is shown in the figure. Figure 2 The cross-sectional view of the process for bonding the upper and lower substrates is shown.

[0019] Figure 11 The display shows Figure 8 The flowchart shows an example of a substrate edge bonding operation.

[0020] Figure 12 and Figure 13 The display shows the connection. Figure 4 and Figure 5 The image shows a cross-sectional view of the treatment of the edges of the upper and lower substrates. Detailed Implementation

[0021] Figure 1 This is a plan view illustrating a substrate bonding apparatus 100 according to an exemplary embodiment of the present invention. Figure 2 It shows along Figure 1 The cross-sectional view taken from lines I-I' and II-II'.

[0022] refer to Figure 1 and Figure 2 The substrate bonding apparatus 100 can be a wafer bonding apparatus. In an exemplary embodiment, the substrate bonding apparatus 100 may include an upper chuck 110 and a lower chuck 120. The upper chuck 110 and the lower chuck 120 may be configured such that an upper substrate W1 and a lower substrate W2 are respectively fixed thereon and the upper substrate W1 and the lower substrate W2 are bonded to each other between the upper chuck 110 and the lower chuck 120. For example, as Figure 2 As shown, the upper substrate W1 can be fixed on the upper chuck 110, the lower substrate W2 can be fixed on the lower chuck 120, and the upper substrate W1 can be coupled to the lower substrate W2, as described below.

[0023] The upper chuck 110 may be disposed on the lower chuck 120. The upper chuck 110 may include, for example, an elastic material, such as rubber or polydimethylsiloxane (PDMS). However, the upper chuck 110 is not limited thereto. The upper chuck 110 may have a first suction hole 112 and an upwardly convex surface 114.

[0024] The first adsorption aperture 112 can be provided with a vacuum pressure therein. The vacuum pressure can allow the convex surface 114 to adhere tightly to and / or adsorb tightly onto the upper substrate W1. The upper substrate W1 can be, for example, a silicon wafer having a (100) crystal plane. The upper substrate W1 can have a circular shape. The upper substrate W1 can have application processor (AP) devices, memory devices, logic devices, and / or interconnects formed thereon. Alternatively, the upper substrate W1 can be a gallium arsenide wafer or a gallium nitride wafer. However, the upper substrate W1 is not limited to these.

[0025] The convex surface 114 may protrude from the upper chuck 110. For example, the convex surface 114 may protrude in a direction away from the upper chuck 110 and toward the lower chuck 120. Here, when the upper chuck 110 is described as having an convex surface 114 toward the lower chuck 120, it should be understood that the convex surface 114 protrudes toward the lower chuck 120. Figure 2 As shown, the vacuum pressure provided by the first adsorption hole 112 can force the upper substrate W1 to bend along the upper convex surface 114 and toward the lower chuck 120. In an exemplary embodiment, the upper convex surface 114 may have a height represented by the first profile 111. The first profile 111 may have an anisotropic shape. For example, the first profile 111 may be shaped like square circles or squirrels. For example, the first profile 111 may be shaped like a square with rounded corners. The first profile 111 may be shown in such a way that the square circles are rotated along an azimuth direction θ about π / 4 radians (e.g., about 45°) relative to the notch N of the upper substrate W1. The upper substrate W1 may be deformed along the upper convex surface 114 from the center 102a to the edge 104a of the upper substrate W1. When viewed in a plan view, the deformed upper substrate W1 may have a circular shape. For example, the convex surface 114 of the upper chuck 110 can bend the upper substrate W1 into a convex shape without changing the circular shape of the upper substrate W1. In addition, the upper chuck 110 can bond the upper substrate W1 to the lower substrate W2 without changing the circular shape of the upper substrate W1 and / or without deforming the upper substrate W1.

[0026] Figure 3 A plan view showing the chuck 210 according to the comparative example is shown.

[0027] refer to Figure 3 The chuck 210 can be represented by a contour 211, shaped like an isotropic circle. The substrate W can be a silicon wafer with a circular shape and can be bent along the isotropic contour 211 of the chuck 210. The substrate may include a notch N. The substrate W may have an orientation... Figure 3 The prominent shape on the front. Figure 3The substrate W is exaggerated in the diagram to show that, when viewed in a planar view, the curved substrate W does not have a precisely circular shape. For example, when viewed in a planar view, the substrate W may be curved into a square-circle shape. For example, the substrate W may be deformed into a square-circle shape based on the Poisson's ratio of the diagonal direction 13 relative to the cut direction 11 of the substrate W, or the Poisson's ratio of both the diagonal direction 13 and the orthogonal direction 12 relative to the cut direction 11. The substrate W with a square-circle shape may undergo deformation during its bonding. The cut direction 11 and the orthogonal direction 12 may correspond to the vertical and horizontal directions on a plane parallel to the substrate W, respectively. Alternatively, the substrate W may be deformed into a square-circle shape based on the difference in Young's modulus between the cut direction 11 and the diagonal direction 13, or the difference in Young's modulus between the orthogonal direction 12 and the diagonal direction 13.

[0028] Figure 4 The display shows along Figure 1 and Figure 2 The image shows a cross-sectional view of the upper substrate W1 taken from edge 104a.

[0029] Reference Figure 1 , Figure 2 and Figure 4 Because ridges and valleys are formed, for example, in the convex surface 114, the convex surface 114 may be uneven, non-uniform, or irregular along the azimuth direction θ of the upper chuck 110. In an exemplary embodiment, the convex surface 114 of the upper chuck 110 may include a first ridge 116 and a first valley 118. The first ridge 116 and the first valley 118 may be alternately arranged along the azimuth direction θ. For example, the first ridge 116 and the first valley 118 may be alternately arranged along the azimuth direction θ at approximately π / 4 radians. The first ridge 116 may be located at approximately 0 radians, approximately π / 2 radians, approximately π radians, approximately 3π / 2 radians, and approximately 2π radians, and the first valley 118 may be located at approximately π / 4 radians, approximately 3π / 4 radians, approximately 5π / 4 radians, and approximately 7π / 4 radians.

[0030] The first ridge 116 may be higher than the first valley 118. For example, the thickness of the upper convex surface 114 may be greater at the first ridge 116 than at the first valley 118. The first ridge 116 may support the upper substrate W1 in the cutting direction 11 (e.g., about π radians and about 2π radians) and the orthogonal direction 12 (e.g., about π / 2 radians and about 3π / 2 radians). For example, the first ridge 116 may support the first ridge portion 106a of the upper substrate W1 from the center 102a of the upper substrate W1 to the edge 104a of the upper substrate W1. The first ridge 116 may have a first radius of curvature R1. For example, when the upper substrate W1 has a diameter of about 30 cm, the first radius of curvature R1 may be about 2 m. A pair of facing first ridges 116 may be spaced apart from each other by a first maximum straight-line distance D1. The first maximum straight-line distance D1 may be about 29 cm.

[0031] The first valley 118 may be lower than the first ridge 116. The first valley 118 may support the upper substrate W1 in a diagonal direction 13 (e.g., approximately π / 4 radians, approximately 3π / 4 radians, approximately 5π / 4 radians, and approximately 7π / 4 radians) between the cutting direction 11 and the orthogonal direction 12. For example, the first valley 118 may support a first valley portion 108a of the upper substrate W1 from the center 102a of the upper substrate W1 to the edge 104a of the upper substrate W1. The first valley 118 may have a second radius of curvature R2. The second radius of curvature R2 may be smaller than the first radius of curvature R1. In this case, the first valley 118 may have a curvature greater than the curvature of the first ridge 116. The curvature of the first ridge 116 may be the reciprocal of the first radius of curvature R1 (1 / R1), and the curvature of the first valley 118 may be the reciprocal of the second radius of curvature R2 (1 / R2). For example, when the upper substrate W1 has a diameter of approximately 30 cm, the second radius of curvature R2 can be approximately 1.8 m. Therefore, in the exemplary embodiment, the first ridge 116 has a first radius of curvature R1, the first valley 118 has a second radius of curvature R2, the first radius of curvature R1 is greater than the second radius of curvature R2, the first ridge 116 has a first curvature, the first valley 118 has a second curvature, and the first curvature is less than the second curvature. A pair of facing first valleys 118 can be spaced apart from each other by a second maximum straight-line distance D2 that is less than the first maximum straight-line distance D1. For example, the second maximum straight-line distance D2 between a pair of facing first valleys 118 can be approximately 28 cm.

[0032] Return to reference Figure 1 and Figure 2The lower chuck 120 may be disposed below the upper chuck 110. The lower chuck 120 may comprise the same material as the upper chuck 110. For example, the lower chuck 120 may comprise an elastic material, such as rubber or polydimethylsiloxane (PDMS). The lower chuck 120 may have a convex shape that is away from the upper chuck 110 and towards it. However, the lower chuck 120 is not limited thereto. For example, in an exemplary embodiment, the lower chuck 120 may be substantially flat. The lower chuck 120 may have a second suction hole 122 and a convex lower surface 124.

[0033] The second adsorption hole 122 can provide a vacuum pressure therein. The vacuum pressure allows the lower convex surface 124 to adhere tightly to and / or adsorb tightly onto the lower substrate W2. The lower substrate W2 can be, for example, a silicon wafer with a circular shape. The lower substrate W2 can have devices that are the same as or different from those formed on the upper substrate W1. For example, the lower substrate W2 can have application processor (AP) devices, memory devices, logic devices, and / or interconnects disposed thereon.

[0034] The convex surface 124 may protrude in a direction away from the lower chuck 120 and toward the upper chuck 110. For example, the convex surface 124 may protrude toward the upper chuck 110. Here, when the lower chuck 120 is described as having a convex surface 124 toward the upper chuck 110, it should be understood that the convex surface 124 protrudes toward the upper chuck 110. The convex surface 124 may have a height represented by a second profile 121. The second profile 121 may overlap with the first profile 111. The vacuum pressure provided by the second suction hole 122 may force the lower substrate W2 to bend along the second profile 121 of the convex surface 124. When viewed in a plan view, the lower substrate W2 may have a circular shape. The convex surface 124 may bend the lower substrate W2 into a convex shape without changing the circular shape of the lower substrate W2.

[0035] Figure 5 The display shows along Figure 1 and Figure 2 The image shows a cross-sectional view of the lower substrate W2 taken from the edge of the lower substrate W2.

[0036] refer to Figure 1 , Figure 2 and Figure 5The convex surface 124 along the azimuth direction θ of the lower chuck 120 may be uneven, non-uniform, or irregular. In an exemplary embodiment, the convex surface 124 of the lower chuck 120 may include a second ridge 126 and a second valley 128. The second ridge 126 and the second valley 128 may be alternately arranged along the azimuth direction θ. For example, the second ridge 126 and the second valley 128 may be alternately arranged along the azimuth direction θ at approximately π / 4 radians. The second ridge 126 may be located at approximately 0 radians, approximately π / 2 radians, approximately π radians, approximately 3π / 2 radians, and approximately 2π radians, and the second valley 128 may be located at approximately π / 4 radians, approximately 3π / 4 radians, approximately 5π / 4 radians, and approximately 7π / 4 radians.

[0037] The second ridge 126 may be higher than the second valley 128. For example, the thickness of the lower convex surface 124 may be greater at the second ridge 126 than at the second valley 128. The second ridge 126 may support the lower substrate W2 in the cut direction 11 or orthogonal direction 12. The second ridge 126 may support the second ridge portion 106b of the lower substrate W2 from the center 102b of the lower substrate W2 to the edge 104b of the lower substrate W2. In an exemplary embodiment, the second ridge 126 may have a radius of curvature approximately the same as the first radius of curvature R1 of the first ridge 116. For example, the second ridge 126 may have a first radius of curvature R1. A pair of facing second ridges 126 may be spaced apart from each other by a first maximum linear distance D1. The first maximum linear distance D1 may be approximately 29 cm.

[0038] The second valley 128 may be lower than the second ridge 126. The second valley 128 may support the lower substrate W2 in the diagonal direction 13. The second valley 128 may support the second valley portion 108b of the lower substrate W2 from the center 102b of the lower substrate W2 to the edge 104b of the lower substrate W2. In an exemplary embodiment, the second valley 128 may have a second radius of curvature R2 smaller than the first radius of curvature R1. For example, when the lower substrate W2 has a diameter of about 30 cm, the second radius of curvature R2 may be about 1.5 m. A pair of facing second valleys 128 may be spaced apart from each other by a second maximum straight-line distance D2. The second maximum straight-line distance D2 may be about 28 cm.

[0039] Figure 6 The diagram shows the display along each direction. Figure 1 Cross-sectional views of the upper chuck 110 and lower chuck 120 taken by lines I-I' and II-II'.

[0040] refer to Figure 6The upper chuck 110 may include an upper electrode 113, and the lower chuck 120 may include a lower electrode 123. When an electrostatic voltage Vs is applied to the upper electrode 113 and the lower electrode 123, the electrostatic voltage Vs can fix the upper substrate W1 and the lower substrate W2 onto the upper convex surface 114 and the lower convex surface 124, respectively. The upper convex surface 114 and the lower convex surface 124 can be coupled to... Figure 2 The upper convex surface 114 and the lower convex surface 124 shown are configured identically. Therefore, for ease of explanation, further description thereof is omitted.

[0041] The substrate bonding method using the substrate bonding apparatus 100 described above will now be described.

[0042] Figure 7 A flowchart illustrating a substrate bonding method according to an exemplary embodiment of the present invention is shown.

[0043] refer to Figure 7 The substrate bonding method may include: fixing the upper substrate W1 (S100), fixing the lower substrate W2 (S200), and bonding the upper substrate W1 and the lower substrate W2 to each other (S300). The process is described in further detail below.

[0044] refer to Figure 1 , Figure 2 , Figure 4 and Figure 7The upper substrate W1 can be fixed to the upper chuck 110 (S100). This can be achieved, for example, by placing the upper substrate W1 below the upper chuck 110 using a robotic arm, and by fixing the upper substrate W1 to the upper convex surface 114 using the vacuum pressure or electrostatic voltage Vs of the first adsorption hole 112 of the upper chuck 110. The vacuum pressure of the first adsorption hole 112 can be sequentially set from the center 102a of the upper substrate W1 to the edge 104a of the upper substrate W1. For example, the vacuum pressure can be provided first by the first adsorption hole 112 at the center 102a of the upper substrate W1, and then sequentially by the first adsorption holes 112 arranged in a direction away from the center 102a of the upper substrate W1 to the edge 104a of the upper substrate W1, until the first adsorption hole 112 at the edge 104a finally provides the vacuum pressure. Therefore, the upper substrate W1 can be gradually bent from the center 102a of the upper substrate W1 to the edge 104a of the upper substrate W1. The upper substrate W1 can be bent along the upper convex surface 114. When the upper substrate W1 is fixed to the convex surface 114, it can be bent while maintaining its circular shape when viewed in a plan view. The edge 104a of the upper substrate W1 can be bent to have different heights along the azimuth direction θ. The edge 104a of the upper substrate W1 can have a first ridge 106a and a first valley 108a. The first ridge 106a can be less bent than the first valley 108a. The first valley 108a can have a greater curvature than the first ridge 106a. The first ridge 106a and the first valley 108a can be formed alternately in the azimuth direction θ at approximately π / 4 radians. The first ridge 106a can be formed along the cut direction 11 (e.g., approximately 0 radians, approximately π radians, and approximately 2π radians) and the orthogonal direction 12 (e.g., approximately π / 2 radians and approximately 3π / 2 radians).

[0045] The lower substrate W2 can be fixed on the lower chuck 120 (S200). This can be achieved, for example, by placing the lower substrate W2 on the lower chuck 120 by a robotic arm, and by fixing the lower substrate W2 on the lower convex surface 124 by the vacuum pressure or electrostatic voltage Vs of the second adsorption hole 122 of the lower chuck 120. Alternatively, the lower substrate W2 can be loaded onto the lower chuck 120 when the lower chuck 120 is flat. The vacuum pressure of the second adsorption hole 122 can be provided sequentially from the center 102b to the edge 104b of the lower substrate W2. For example, the vacuum pressure can be provided first by the second adsorption hole 122 at the center 102b of the lower substrate W2, and then sequentially by the second adsorption holes 122 arranged in a direction away from the center 102b of the lower substrate W2 to the edge 104b of the lower substrate W2, until the second adsorption hole 122 at the edge 104b finally provides the vacuum pressure. The lower substrate W2 can be gradually bent from the center 102b to the edge 104b of the lower substrate W2.

[0046] The lower substrate W2 can be bent along the convex surface 124. When the lower substrate W2 is fixed to the convex surface 124, it can be bent while maintaining its circular shape when viewed in a plan view. The edge 104b of the lower substrate W2 can be bent to have different heights along the azimuth direction θ. The edge 104b of the lower substrate W2 can have a second ridge 106b and a second valley 108b. The second ridge 106b can be bent less than the second valley 108b. The second valley 108b can have a greater curvature than the second ridge 106b. For example, the second ridge 106b and the second valley 108b can be formed alternately in the azimuth direction θ at approximately π / 4 radians. The second ridge 106b can be formed along the cut direction 11 (e.g., approximately 0 radians, approximately π radians, and approximately 2π radians) and the orthogonal direction 12 (e.g., approximately π / 2 radians and approximately 3π / 2 radians).

[0047] Upper substrate W1 and lower substrate W2 can be bonded to each other (S300). This can be achieved, for example, by lowering upper chuck 110 toward lower chuck 120. When upper chuck 110 and lower chuck 120 come close to each other, upper substrate W1 and lower substrate W2 can be bonded to each other. Each of upper substrate W1 and lower substrate W2 can have an adhesive dielectric layer used during the bonding process.

[0048] Figure 8 The display shows Figure 7 The flowchart shows an example of substrate bonding operation S300.

[0049] refer to Figure 8 The operation S300 of joining the upper substrate W1 and the lower substrate W2 may include joining the center 102a of the upper substrate W1 and the center 102b of the lower substrate W2 (S310), and joining the edge 104a of the upper substrate W1 and the edge 104b of the lower substrate W2 (S320). For example, in an exemplary embodiment, in operation S310, the center 102a of the upper substrate W1 and the center 102b of the lower substrate W2 may first join each other, and after the centers 102a and 102b are joined together, the edge 104a of the upper substrate W1 and the edge 104b of the lower substrate W2 may subsequently join each other.

[0050] Figure 9 and Figure 10 It is shown in the figure. Figure 2 The cross-sectional view of the process for bonding the upper substrate W1 and the lower substrate W2 is shown.

[0051] refer to Figure 8 and Figure 9The upper chuck 110 and lower chuck 120 can bond the center 102a of the upper substrate W1 to the center 102b of the lower substrate W2 (S310). The upper chuck 110 can move toward the lower chuck 120. For example, the upper substrate W1 can be adhered to the upper chuck 110, the lower substrate W2 can be adhered to the lower chuck 120, and the upper chuck 110 can move toward the lower chuck 120. When the center 102a of the upper substrate W1 and the center 102b of the lower substrate W2 are bonded to each other, the vacuum pressure can be removed from the first adsorption hole 112 corresponding to the center 102a of the upper substrate W1 and the second adsorption hole 122 corresponding to the center 102b of the lower substrate W2, or the electrostatic voltage Vs can be removed from the upper electrode 113 and the lower electrode 123.

[0052] refer to Figure 8 and Figure 10 The upper chuck 110 and lower chuck 120 can engage the edge 104a of the upper substrate W1 to the edge 104b of the lower substrate W2 (S320). After the centers 102a of the upper substrate W1 and 102b of the lower substrate W2 are engaged with each other, the edges 104a of the upper substrate W1 and 104b of the lower substrate W2 can be engaged with each other. When the upper chuck 110 and lower chuck 120 are tightly coupled with each other, the upper substrate W1 and the lower substrate W2 can be gradually engaged from their centers 102a and 102b to their edges 104a and 104b. The upper convex surface 114 and the lower convex surface 124 can become substantially flat due to their diametrical direction and / or their outward extension. For example, as the upper substrate W1 and the lower substrate W2 are gradually engaged from their centers 102a and 102b to their edges 104a and 104b, the upper convex surface 114 and the lower convex surface 124 can become substantially flat. The upper chuck 110 and the lower chuck 120 may each have a diameter D3 greater than the first maximum linear distance D1 and the second maximum linear distance D2. The diameter D3 of each of the upper chuck 110 and the lower chuck 120 may be substantially the same as the diameter of each of the upper substrate W1 and the lower substrate W2.

[0053] Figure 11 The display shows Figure 8 The flowchart shows an example of the edge joining operation S320.

[0054] refer to Figure 11 The operation S320 of joining the edge 104a of the upper substrate W1 and the edge 104b of the lower substrate W2 may include joining the first ridge 106a and the second ridge 106b to each other (S322) and joining the first valley 108a and the second valley 108b to each other (S324).

[0055] Figure 12 and Figure 13 The image shows the connection in Figure 4and Figure 5 Cross-sectional view of the process of edge 104a of upper substrate W1 and edge 104b of lower substrate W2 shown.

[0056] refer to Figure 11 and Figure 12 The first ridge 116 of the upper chuck 110 and the second ridge 126 of the lower chuck 120 can engage the first ridge 106a of the upper substrate W1 and the second ridge 106b of the lower substrate W2 (S322). For example, in an exemplary embodiment, as the upper chuck 110 moves toward the lower chuck 120, the first ridge 116 of the upper chuck 110 can move toward the second ridge 126 of the lower chuck 120, such that the first ridge 106a of the upper substrate W1 contacts the second ridge 106b of the lower substrate W2.

[0057] like Figure 12 As shown, in an exemplary embodiment, the second valley 128 may be aligned with and disposed on the first valley 118, and the second ridge 126 may be aligned with and disposed on the first ridge 116.

[0058] refer to Figure 11 and Figure 13 The first valley 118 of the upper chuck 110 and the second valley 128 of the lower chuck 120 can engage the first valley 108a of the upper substrate W1 and the second valley 108b of the lower substrate W2 (S324). For example, in an exemplary embodiment, as the upper chuck 110 moves toward the lower chuck 120, the first valley 118 of the upper chuck 110 can move toward the second valley 128 of the lower chuck 120, such that the first valley 108a of the upper substrate W1 contacts the second valley 108b of the lower substrate W2. When viewed in a plan view, the engaged upper substrate W1 and lower substrate W2 can have their circular shapes and can be substantially flat without distortion along the azimuth direction θ.

[0059] Alternatively, in an exemplary embodiment, the upper chuck 110 may stop its descent when the center 102a of the upper substrate W1 engages with the center 102b of the lower substrate W2. When the upper chuck 110 stops its descent, the vacuum pressure of the first adsorption hole 112 and the second adsorption hole 122 can be gradually removed from the centers 102a and 102b toward the edges 104a and 104b. When the vacuum pressure of the first adsorption hole 112 and the second adsorption hole 122 is gradually removed in this manner, the upper substrate W1 and the lower substrate W2 can engage from their centers 102a and 102b toward their edges 104a and 104b. Therefore, the upper substrate W1 and the lower substrate W2 can engage substantially flatly along the azimuth direction θ without deformation. In addition, the formation of air bubbles between the upper substrate W1 and the lower substrate W2 can be avoided.

[0060] According to an exemplary embodiment of the present invention, the substrate bonding apparatus can be configured to bend the substrate into a protruding shape corresponding to the convex shape of the chuck (including ridges and valleys along the azimuth direction of the chuck) without altering the circular shape of the substrate. Therefore, substrate deformation can be prevented during the bonding process.

[0061] Although the inventive concept has been specifically shown and described with reference to exemplary embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of the inventive concept as defined by the appended claims.

Claims

1. A substrate bonding apparatus, comprising: The lower chuck receives the lower substrate. as well as The upper chuck is positioned above the lower chuck. The upper substrate is fixed to the upper chuck, and the upper chuck and the lower chuck join the upper substrate and the lower substrate. The upper chuck has an upwardly convex surface facing the lower chuck. The convex surface includes a plurality of first ridges and a plurality of first valleys arranged alternately along the azimuth direction. The first ridge has a first radius of curvature, the first valley has a second radius of curvature, and the first radius of curvature is greater than the second radius of curvature.

2. The substrate bonding apparatus according to claim 1, wherein, The first ridge and the first valley are arranged alternately at π / 4 radians along the azimuth direction.

3. The substrate bonding apparatus according to claim 2, wherein, The first ridge is arranged along the azimuth direction at π / 2 radians, π radians, 3π / 2 radians, and 2π radians, and The first valley is arranged at π / 4 radians, 3π / 4 radians, 5π / 4 radians, and 7π / 4 radians along the azimuth direction.

4. The substrate bonding apparatus according to claim 1, wherein, The first ridge has a first curvature, the first valley has a second curvature, and the first curvature is less than the second curvature.

5. The substrate bonding apparatus according to claim 1, wherein, The lower chuck has a downwardly convex surface facing the upper chuck, and The convex surface includes a plurality of second ridges and a plurality of second valleys arranged alternately along the azimuth direction.

6. The substrate bonding apparatus according to claim 5, wherein, The second valley is arranged on top of the first valley, and The second ridge is arranged on the first ridge.

7. The substrate bonding apparatus according to claim 5, wherein, The second ridge has the first radius of curvature, and The second valley has the second radius of curvature.

8. The substrate bonding apparatus according to claim 1, wherein, The upper chuck includes a plurality of first adsorption holes, which vacuum adsorb the upper substrate onto the upper chuck, and The lower chuck includes a plurality of second adsorption holes, which vacuum adsorb the lower substrate onto the lower chuck.

9. The substrate bonding apparatus according to claim 1, wherein, The upper chuck includes an upper electrode that electrostatically fixes the upper substrate to the upper chuck, and The lower chuck includes a lower electrode that electrostatically fixes the lower substrate to the lower chuck.

10. A substrate bonding apparatus, comprising: The lower chuck loads the lower substrate. as well as The upper chuck is positioned above the lower chuck. The upper substrate is fixed to the upper chuck, and the upper chuck and the lower chuck engage the upper substrate and the lower substrate. The upper chuck has an upwardly convex surface facing the lower chuck, and this upwardly convex surface is not flat along the azimuth direction. The lower chuck has a convex surface facing the upper chuck, and the convex surface is not flat along the azimuth direction.

11. The substrate bonding apparatus according to claim 10, wherein, The convex surface includes: Multiple ridges; and Multiple valleys are arranged between and below the ridges.

12. The substrate bonding apparatus according to claim 11, wherein, A pair of facing ridges are separated from each other by a first maximum straight-line distance, and A pair of facing valleys are separated from each other by a second maximum straight-line distance, which is less than the first maximum straight-line distance.

13. The substrate bonding apparatus according to claim 10, wherein, The upper chuck comprises rubber or polydimethylsiloxane.

14. A substrate bonding method, comprising the steps of: Secure the upper substrate to the upper chuck; as well as The upper substrate and the lower substrate are joined together, wherein, The lower substrate is disposed on the lower chuck facing the upper chuck. The step of bonding the upper substrate to the lower substrate includes: Joining the center of the upper substrate with the center of the lower substrate; and Join the edge of the upper substrate with the edge of the lower substrate. The step of joining the edge of the upper substrate with the edge of the lower substrate includes: The plurality of first ridges of the upper substrate are joined to the plurality of second ridges of the lower substrate; as well as The plurality of first valleys arranged between the first ridges are joined with the plurality of second valleys arranged between the second ridges.

15. The substrate bonding method according to claim 14, wherein, The first ridge is arranged along the cut direction of the upper substrate and along the orthogonal direction of the upper substrate, the orthogonal direction of the upper substrate being substantially perpendicular to the cut direction of the upper substrate. The cut direction and the orthogonal direction of the upper substrate correspond to the vertical and horizontal directions on a plane parallel to the upper substrate, respectively. The second ridge is arranged along the cut direction of the lower substrate and along the orthogonal direction of the lower substrate, the orthogonal direction of the lower substrate being substantially perpendicular to the cut direction of the lower substrate, the cut direction of the lower substrate and the orthogonal direction corresponding to the vertical and horizontal directions on a plane parallel to the lower substrate, respectively.

16. The substrate bonding method according to claim 15, wherein, The first ridge and the second ridge are positioned at π / 2 radians, π radians, 3π / 2 radians, and 2π radians along the azimuth direction of one of the upper chuck and the lower chuck.

17. The substrate bonding method according to claim 15, wherein, The first valley portion is arranged diagonally along the upper substrate, the diagonal direction of which lies between the cut direction and the orthogonal direction of the upper substrate. The second valley is arranged diagonally along the lower substrate, and the diagonal direction of the lower substrate is located between the cut direction and the orthogonal direction of the lower substrate.

18. The substrate bonding method according to claim 17, wherein, The first valley and the second valley are positioned at π / 4 radians, 3π / 4 radians, 5π / 4 radians, and 7π / 4 radians along the azimuth direction of one of the upper chuck and the lower chuck.

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