Method of forming an optical module

Abstract

The present disclosure relates to methods of forming optical modules. Optical modules and methods of forming the same are provided. In one embodiment, an exemplary method includes forming a plurality of first optical elements over a first wafer, forming a plurality of second optical elements over a second wafer, forming a plurality of third optical elements over a third wafer, aligning the first wafer with the second wafer such that, upon alignment of the first wafer with the second wafer, each first optical element vertically overlaps a corresponding second optical element. The method further includes bonding the first wafer with the second wafer to form a first bonded structure, aligning the second wafer with the third wafer such that, upon alignment of the second wafer with the third wafer, each second optical element vertically overlaps a corresponding third optical element when the second wafer of the first bonded structure is bonded to the third wafer.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductors, and more specifically, to a method for forming an optical module. Background Technology

[0002] The semiconductor integrated circuit (IC) industry has experienced exponential growth. Technological advancements in IC materials and design have resulted in generations of ICs, each generation smaller and more complex than the last. Throughout IC evolution, functional density (the number of interconnect modules per chip area) has generally increased, while geometry (the smallest component (or line) that can be created using manufacturing processes) has decreased. This scaling down process typically provides benefits through increased production efficiency and reduced associated costs.

[0003] Despite advancements in semiconductor manufacturing, existing methods for forming optical modules may still require improvement. For example, each optical module may be formed by aligning and assembling multiple individual optical elements, resulting in bulky modules, complex assembly processes, and increased costs. Therefore, while existing methods for forming optical modules are generally sufficient, they are not satisfactory in all aspects. Summary of the Invention

[0004] A first aspect of this disclosure relates to a method for forming a semiconductor structure, comprising: forming a plurality of first optical elements on a first wafer; forming a plurality of second optical elements on a second wafer; aligning the first wafer and the second wafer, wherein, after aligning the first wafer and the second wafer, each of the plurality of first optical elements vertically overlaps with a corresponding second optical element among the plurality of second optical elements; bonding the first wafer and the second wafer after aligning the first wafer and the second wafer to obtain a first bonding structure; forming a plurality of third optical elements on a third wafer; aligning the second wafer of the first bonding structure with the third wafer, wherein, after aligning the second wafer and the third wafer, each of the plurality of second optical elements vertically overlaps with a corresponding third optical element among the plurality of third optical elements; and bonding the second wafer of the first bonding structure to the third wafer after aligning the second wafer and the third wafer to obtain a second bonding structure.

[0005] A second aspect of this disclosure relates to a method for forming a semiconductor structure, comprising: forming a plurality of first optical elements on a first wafer; forming a plurality of second optical elements on a second wafer; forming a plurality of third optical elements on a third wafer; aligning the first wafer and the second wafer after forming the plurality of first optical elements and the plurality of second optical elements; bonding the first wafer and the second wafer after the alignment of the first wafer and the second wafer; aligning the second wafer and the third wafer after forming the plurality of third optical elements; bonding the first wafer and the second wafer to the third wafer after the alignment of the second wafer and the third wafer to obtain a bonding structure; and dicing the bonding structure to form a plurality of first optical modules, wherein each of the plurality of first optical modules includes one of the plurality of first optical elements, one of the plurality of second optical elements, and one of the plurality of third optical elements, and wherein each of the plurality of first optical modules includes a vertical sidewall.

[0006] A third aspect of this disclosure relates to an optical module comprising: a first substrate; an image sensor disposed on and electrically coupled to the first substrate; a first adhesive layer disposed on the image sensor; a second substrate disposed on the image sensor and attached to the image sensor via the first adhesive layer; a filter disposed on the second substrate and directly above the image sensor; a third substrate disposed on the filter and attached to the filter via a second adhesive layer; and a lens structure disposed on the third substrate and directly above the image sensor and the filter, wherein the sidewall surface of the first substrate is aligned with the sidewall surface of the second substrate. Attached Figure Description

[0007] When with attachment Figure 1 This disclosure is best understood from the following detailed description. It should be emphasized that, in accordance with industry standard practice, the various features are not drawn to scale and are for illustrative purposes only. In fact, the dimensions of the various features may be increased or decreased arbitrarily for clarity of discussion.

[0008] Figure 1 A flowchart illustrating a method for simultaneously forming a plurality of first optical modules and a plurality of second optical modules according to one or more aspects of the present disclosure is shown.

[0009] Figure 2 , 3 Figures 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, and 22 illustrate one or more aspects of this disclosure. Figure 1 Partial sectional views of the workpiece during each manufacturing stage in the method.

[0010] Figure 23 The illustration shows a flowchart of a first alternative method for forming a plurality of first optical modules and a plurality of second optical modules according to one or more aspects of the present disclosure.

[0011] Figure 24 , 25 Figures 26, 27, 28, 29, 30, 31, 32, and 33 illustrate one or more aspects of this disclosure. Figure 23 Partial sectional views of the workpiece during each manufacturing stage in the method.

[0012] Figure 34 The illustration shows a flowchart of a second alternative method for forming a plurality of first optical modules according to one or more aspects of the present disclosure.

[0013] Figure 35 , 36 Figures 37, 38, 39, 40, 41, 42, and 43 illustrate one or more aspects of this disclosure. Figure 34 Partial sectional views of the workpiece during each manufacturing stage in the method.

[0014] Figure 44 , 45 Figures 46 and 47 illustrate partial sectional views of alternative workpieces during various manufacturing stages according to one or more aspects of this disclosure. Detailed Implementation

[0015] The following disclosure provides numerous different embodiments or examples for implementing various features of the provided subject matter. Specific examples of components and arrangements are described below to simplify this disclosure. Of course, these are merely examples and are not intended to be limiting. For example, in the following description, forming a first feature on or over a second feature can include embodiments where the first and second features are formed in direct contact, and can also include embodiments where additional features can be formed between the first and second features such that the first and second features do not need to be in direct contact. Furthermore, reference numerals and / or letters may be repeated in various examples. Such repetition is for simplicity and clarity and does not, in itself, prescribe a relationship between the various embodiments and / or configurations discussed.

[0016] For ease of description, this document uses spatially relative terms such as “below,” “under,” “down,” “above,” and “up” to describe the relationship between one element or feature and another, as shown in the figure. In addition to the directions depicted in the figure, the spatially relative terms are intended to cover different orientations of the device during use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein will be interpreted accordingly.

[0017] Furthermore, when using terms such as "approximately" or "about," the term is intended to encompass numbers within a reasonable range, taking into account variations inherent in manufacturing as understood by those skilled in the art. For example, based on known manufacturing tolerances associated with a feature having characteristics related to the manufacturing of a number, a number or range encompasses a reasonable range including the described number, such as within + / - 10% of the described number. For instance, a material layer with a thickness of "approximately 5 nm" could encompass a size range from 4.25 nm to 5.75 nm, where manufacturing tolerances associated with the deposited material layer are known to those skilled in the art to be + / - 15%.

[0018] Optical modules are widely used in various devices, such as infrared cameras and dot projectors. Some optical modules may include multiple optical elements. In some existing technologies, each optical element can be manufactured individually, and then these optical elements can be aligned and assembled to form an optical module. Optical modules can be bulky. Furthermore, forming multiple optical modules involves a large and complex assembly process, which adversely increases the associated costs and reduces productivity.

[0019] This disclosure provides a method for forming optical modules. In an exemplary method, each type of optical element can be fabricated on one or more wafers. For example, multiple lens structures can be fabricated on a first wafer, and multiple filter structures can be fabricated on a second wafer. After fabricating the different optical elements on these wafers, wafer-level alignment and bonding processes can then be performed. After the alignment and bonding of these wafers, the optical elements formed on these wafers can be aligned accordingly. A monolithization process can then be performed to diced the bonded wafers into multiple optical modules. By fabricating these optical elements using a semiconductor-comparable process, optical modules with reduced dimensions can be realized. Furthermore, by avoiding repetitive alignment processes for each individual optical module, performing wafer-level alignment can improve overall productivity and reduce associated costs.

[0020] Various aspects of this disclosure will now be described in more detail with reference to the accompanying drawings. In this regard, Figure 1This is a flowchart illustrating a method 100 for forming a plurality of first optical modules and a plurality of second optical modules according to an embodiment of the present disclosure. The following is in conjunction with... Figure 2-22 Description method 100, Figure 2-22 These are partial sectional views of the workpiece at different manufacturing stages according to an embodiment of method 100. Figure 23 This is a flowchart illustrating exemplary operations in an alternative method 300 for forming a plurality of first optical modules and a plurality of second optical modules according to an embodiment of the present disclosure. The following is in conjunction with... Figure 24-33 Description method 300, Figure 24-33 These are partial sectional views of the workpiece at different manufacturing stages according to an embodiment of method 300. Figure 34 This is a flowchart illustrating exemplary operations in another alternative method 500 for forming a plurality of first optical modules according to an embodiment of the present disclosure. The following is in conjunction with... Figures 35-46 Description method 500, Figures 35-46 This is a partial sectional view of a workpiece at different manufacturing stages according to an embodiment of method 500. Methods 100, 300, and 500 are merely examples and are not intended to limit this disclosure to what is expressly described therein. Additional steps may be provided before, during, and after methods 100, 300, and / or 500, and some described steps may be replaced, eliminated, or moved for additional embodiments of the methods. For simplicity, not all steps are described in detail herein. To avoid misunderstanding, Figure 2-22 The X, Y, and Z directions in 24-33 and 35-46 are perpendicular to each other and are used consistently throughout 2-22, 24-33, and 35-46. Throughout this disclosure, similar reference numerals denote similar features unless otherwise stated.

[0021] refer to Figure 1 , 2 Method 100 includes block 102, at which a first substrate 202A and a second substrate 202B are provided. Each of the first substrate 202A (or first wafer 202A) and the second substrate 202B (or second wafer 202B) may be formed of quartz, fused silica, sapphire, or other suitable material that is transparent to the wavelength of the light of interest. In some embodiments, each of the first substrate 202A and the second substrate 202B includes a plurality of alignment marks. For example, the first substrate 202A includes two alignment marks 203, and the second substrate 202B includes two alignment marks 205. It will be understood that... Figure 2 and Figure 3 The arrangement (e.g., position, shape, size) and quantity of alignment marks 203 / 205 shown are merely examples. Other arrangements and quantities (e.g., three or more) are possible. In this embodiment, the top view dimensions and shape of the first substrate 202A are the same as those of the second substrate 202B.

[0022] refer to Figure 1 , 2 Methods 100 include block 104, at which an upper portion 208a of a beam splitter 208 is formed over a first substrate 202A. (See reference...) Figure 2 A first material layer 204 is disposed on a first substrate 202A. The first material layer 204 may be formed on the first substrate 202A using atomic layer deposition (ALD), physical vapor deposition (PVD), chemical vapor deposition (CVD), or other suitable methods. The first material layer 204 may include a metal (e.g., aluminum), a dielectric material (e.g., silicon nitride), or any other suitable material.

[0023] refer to Figure 4 After forming the first material layer 204, a mask film is deposited on the first substrate 202A using CVD or ALD, and then patterned by photolithography to form a patterned mask film 206. An exemplary photolithography process includes spin-coating a photoresist layer, soft baking of the photoresist layer, mask alignment, exposure, post-exposure baking, development of the photoresist layer, rinsing, and drying (e.g., hard baking). The patterned mask film 206 exposes the portion of the first material layer 204 disposed directly above a first region R1 of the first substrate 202A. While using the patterned mask film 206 as an etching mask, an etching process is performed to remove the portion of the first material layer 204 exposed by the patterned mask film 206. In some embodiments, the first region R1 of the first substrate 202A may be based on other optical elements (e.g., Figure 19 The configuration of the image sensor 236 shown, along with the positional relationships between other optical elements and corresponding alignment marks, is determined. The patterned mask 206 can then be selectively removed.

[0024] refer to Figure 6 After removing the patterned mask 206, further processes such as photolithography and etching can be performed on the remaining portion of the first material layer 204 to form a beam splitter 208 directly above the second region R2 of the first substrate 202A. Figure 10 The upper portion 208a of the beam splitter 208 (as shown) may include trenches (e.g., trench 208T) formed in the first material layer 204. It is understood that... Figure 6 The shape of the cross-sectional view of the upper portion 208a of the beam splitter 208 shown is merely an example and is not intended to limit this disclosure to the contents explicitly illustrated therein.

[0025] refer to Figure 1 , 3 5, 7, Method 100 includes block 106, at which a lower portion 208b of beam splitter 208 is formed on a second substrate 202B. Reference Figure 3 A second material layer 210 is disposed on the second substrate 202B. The composition and formation of the second material layer 210 can be similar to those of the first material layer 204. In one embodiment, the composition of the second material layer 210 is the same as that of the first material layer 204.

[0026] After the formation of the second material layer 210, in Figure 5 In the illustrated embodiment, a patterned mask 212 is formed on the second material layer 210. The patterned mask 212 exposes the portion of the second material layer 210 directly above the first region R1' of the second substrate 202B. The formation of the patterned mask 212 can be similar to the formation of the patterned mask 206. An etching process can then be performed to remove the portion of the second material layer 210 directly above the first region R1' of the second substrate 202B. The patterned mask 212 can then be selectively removed. In this embodiment, the top-view dimensions and shape of the first region R1' of the second substrate 202B are substantially the same as those of the first region R1 of the first substrate 202A, and the positional relationship between the first region R1' of the second substrate 202B and the alignment mark 205 corresponds to the positional relationship between the first region R1 of the first substrate 202A and the alignment mark 203, such that when the first substrate 202A is flipped and aligned with the second substrate 202B, the first region R1 of the first substrate 202A will be aligned with the first region R1' of the second substrate 202B. That is, after the first substrate 202A is flipped and aligned with the second substrate 202B, the boundaries and center lines of the first region R1 of the first substrate 202A and the first region R1' of the second substrate 202B are aligned.

[0027] refer to Figure 7 After removing the patterned mask 212, further processes such as photolithography and etching can be performed on the remaining portion of the second material layer 210 to form a beam splitter 208 directly above the second region R2' of the second substrate 202B. Figure 10 The lower portion 208b of the beam splitter 208 (as shown) may include a trench (e.g., trench 208T'). It is understood that... Figure 7The shape of the cross-sectional view of the lower portion 208b of the beam splitter 208 shown is merely an example and is not intended to limit this disclosure to the content explicitly illustrated therein. The position and configuration of the lower portion 208b of the beam splitter 208 formed on the second substrate 202B can be determined based on the desired position and configuration of the beam splitter 208 and the corresponding position and configuration of the upper portion 208a of the beam splitter 208 formed on the first substrate 202A. In an embodiment, a second region R2' of the second substrate 202B is defined such that when the first substrate 202A is flipped and aligned with the second substrate 202B, the combination of the upper portion 208a of the beam splitter 208 formed on the first substrate 202A and the lower portion 208b of the beam splitter 208 formed on the second substrate 202B forms a beam splitter 208 having satisfactory optical functionality (one or more).

[0028] refer to Figure 1 , 8 Method 100 includes block 108, at which a first adhesive layer 214a is formed on a first substrate 202A and a second adhesive layer 214b is formed on a second substrate 202B. The first adhesive layer 214a and the second adhesive layer 214b are configured to facilitate bonding between the first substrate 202A and the second substrate 202B. In an embodiment, the first adhesive layer 214a is formed not only on and around the upper portion 208a of the beam splitter 208, but also fills trenches (e.g., trench 208T) of the upper portion 208a of the beam splitter 208. The first adhesive layer 214a is also formed directly above a first region R1 of the first substrate 202A. The second adhesive layer 214b is formed not only on and around the lower portion 208b of the beam splitter 208, but also fills trenches (e.g., trench 208T') of the lower portion 208b of the beam splitter 208. The second adhesive layer 214b is also formed directly above the first region R1' of the second substrate 202B. The first adhesive layer 214a and the second adhesive layer 214b can comprise any suitable material having a low light absorption coefficient (or absorptivity), such as a benzocyclobutene (BCB) polymer, and can be deposited using any suitable method. The first adhesive layer 214a can be formed before or after the formation of the second adhesive layer 214b. In some other embodiments, the first adhesive layer 214a and the second adhesive layer 214b can be formed simultaneously.

[0029] refer to Figure 1 and Figure 10 Method 100 includes block 110, where a first substrate 202A is flipped. Figure 8 The workpiece shown is flipped over, as... Figure 10 As shown, the first substrate 202A is located on top and disposed on the first material layer 204 (including the upper part 208a of the beam splitter 208).

[0030] refer to Figure 1 and Figure 10 Method 100 includes block 112, where a first substrate 202A and a second substrate 202B are aligned. (See above reference...) Figure 2-3 As described, the first substrate 202A includes alignment marks 203, and the second substrate 202B includes alignment marks 205. In the illustrated embodiment, after the first substrate 202A is flipped, the second substrate 202B can be laterally moved until each alignment mark 205 in the second substrate 202B is aligned with a corresponding alignment mark 203 in the first substrate 202A. That is, a wafer-level alignment process is performed to align the second substrate 202B with the first substrate 202A. In the embodiment, after the first substrate 202A is flipped and aligned with the second substrate 202B, a first region R1 of the first substrate 202A is aligned with a first region R1' of the second substrate 202B, and a second region R2 of the first substrate 202A is aligned with a second region R2' of the second substrate 202B. Because the alignment process is a wafer-level alignment process, high alignment accuracy can be obtained. In one embodiment, after alignment between the first substrate 202A and the second substrate 202B, the distance between the center line of the first region R1 of the first substrate 202A and the center line of the first region R1' of the second substrate 202B can be less than 10 μm. In some embodiments, there is essentially no offset between the center lines of the first region R1 and the center lines of the first region R1'. The same applies to the second regions R2 and R2'.

[0031] refer to Figure 1 and Figure 10 Method 100 includes a block 114, at which a first substrate 202A is bonded to a second substrate 202B. After the first substrate 202A and the second substrate 202B are aligned, a first adhesive layer 214a directly faces the second adhesive layer 214b. In embodiments, the composition of the first adhesive layer 214a is the same as that of the second adhesive layer 214b, and the first adhesive layer 214a and the second adhesive layer 214b can be referred to separately or collectively as adhesive layer 214 (…). Figure 10 (As shown). In some embodiments, the first substrate 202A is bonded to the second substrate 202B via a thermo-press bonding process (e.g., including heating and thermal and mechanical pressure) or other suitable bonding process. After the first substrate 202A is bonded to the second substrate 202B, the combination of the upper portion 208a and the lower portion 208b of the beam splitter 208 forms the beam splitter 208. Figure 10 In the illustrated embodiment, the upper part 208a of the beam splitter 208 and the lower part 208b of the beam splitter 208 are vertically separated by the combination of the first adhesive layer 214a and the second adhesive layer 214b. Figure 10 The workpiece shown can be referred to as structure 216.

[0032] In some embodiments, such as Figure 11 As shown, after the first substrate 202A is bonded to the second substrate 202B, a thinning process can be performed to thin the first substrate 202A and the second substrate 202B from the back sides of the first and second substrates to reduce the overall thickness of structure 216. The thinning process may include a mechanical polishing process and / or a chemical thinning process. For example, a significant amount of substrate material may first be removed from the first substrate 202A during a first mechanical polishing process. Subsequently, a second mechanical polishing process may be applied to the back side of the second substrate 202B to thin the second substrate 202B.

[0033] refer to Figure 1 , 12 In method 100, a frame 116 is included, at which a first lens structure 220a and a second lens structure 220b are formed on a first predetermined region R1” and a second predetermined region R2” of a third substrate 202C, respectively. The third substrate 202C may be formed of quartz, fused silica, sapphire, or other suitable material that is transparent to the wavelength of the light of interest. The third substrate 202C also includes a plurality of (e.g., two) alignment marks 218. It is understood that the arrangement (e.g., position, shape, size) and number of alignment marks 218 are merely examples. In an embodiment, the top view dimensions and shape of the third substrate 202C are the same as those of the second substrate 202B. That is, when the third substrate 202C is aligned with the second substrate 202B, the boundaries (sidewalls) and centerline of the third substrate 202C are substantially aligned with the boundaries (sidewalls) and centerline of the second substrate 202B.

[0034] To form the first lens structure 220a and the second lens structure 220b, refer to Figure 12 A third material layer 220 is disposed on a third substrate 202C. The third material layer 220 can be formed on the third substrate 202C using atomic layer deposition (ALD), physical vapor deposition (PVD), chemical vapor deposition (CVD), or other suitable methods. The third material layer 220 may include metallic and / or dielectric materials, such as titanium dioxide (TiO2), aluminum oxide, hafnium oxide (HfO2), zinc oxide (ZnO), silicon nitride (Si3N4), other suitable materials, or combinations thereof. After forming the third material layer 220, refer to... Figure 13One or more photolithography processes can be performed to remove excess portions of the third material layer 220 to form a first lens structure 220a directly above a first region R1” of the third substrate 202C and a second lens structure 220b directly above a second region R2” of the third substrate 202C. In one embodiment, both the first lens structure 220a and the second lens structure 220b include planar lens structures, and each planar lens structure may include a plurality of fins 220f formed by the third material layer 220. These fins 220f may have different widths along the X direction.

[0035] In this embodiment, the positional relationship between the first region R1” of the third substrate 202C and the corresponding alignment mark 218 corresponds to the positional relationship between the first region R1' of the second substrate 202B and the alignment mark 205, and the positional relationship between the second region R2” of the third substrate 202C and the alignment mark 218 corresponds to the positional relationship between the second region R2' of the second substrate 202B and the alignment mark 205. Therefore, when the third substrate 202C is aligned with the second substrate 202B, the first region R1” of the third substrate 202C will be aligned with the first region R1' of the second substrate 202B, and the second region R2” of the third substrate 202C will be aligned with the second region R2' of the second substrate 202B.

[0036] refer to Figure 14 After forming the first lens structure 220a and the second lens structure 220b, a third adhesive layer 222 is formed on the third substrate 202C. In an embodiment, the third adhesive layer 222 is formed not only on the fins 220f of the first lens structure 220a and the second lens structure 220b, but also fills the trench between two adjacent fins 220f on the third substrate 202C. The third adhesive layer 222 may comprise any suitable material having a low light absorption coefficient (or absorptivity), such as a benzocyclobutene (BCB) polymer, and may be deposited using any suitable method.

[0037] refer to Figure 1 and Figure 15Method 100 includes a block 118 at which a third substrate 202C is aligned with a second substrate 202B of structure 216. As described above, the second substrate 202B includes alignment marks 205 and the third substrate 202C includes alignment marks 218. The third substrate 202C can be moved laterally until each alignment mark 218 in the third substrate 202C is aligned with a corresponding alignment mark 205 in the second substrate 202B. That is, a wafer-level alignment process is performed to align the third substrate 202C with the second substrate 202B, and a high alignment accuracy can be obtained. Once the third substrate 202C is aligned with the second substrate 202B, the first region R1” of the third substrate 202C is aligned with the first region R1' of the second substrate 202B, and the second region R2” of the third substrate 202C is aligned with the second region R2' of the second substrate 202B. In other words, a beam splitter 208 is formed directly above the second lens structure 220b. After alignment between the third substrate 202C and the second substrate 202B, the distance between the center line of the beam splitter 208 and the center line of the second lens structure 220b can be less than 10 μm. In one embodiment, there is essentially no offset between the center line of the beam splitter 208 and the center line of the second lens structure 220b.

[0038] refer to Figure 1 and Figure 15 Method 100 includes a block 120 where a third substrate 202C is bonded to a second substrate 202B of structure 216. After the third substrate 202C is aligned with the second substrate 202B, a third adhesive layer 222 directly faces the bottom surface of the second substrate 202B. The third substrate 202C can be moved toward the second substrate 202B until the third adhesive layer 222 bonds the third substrate 202C to the bottom surface of the second substrate 202B. In some embodiments, the third substrate 202C is bonded to the second substrate 202B by a thermoforming bonding process or other suitable bonding process. After the third substrate 202C is bonded to the second substrate 202B, Figure 15 In the illustrated embodiment, the beam splitter 208 is formed directly above the second lens structure 220b. Following the bonding process, a thinning process (e.g., mechanical polishing and / or chemical thinning) can be performed to thin the third substrate 202C from the back side. In one embodiment, the thickness T2 of the workpiece comprising the third substrate 202C and the third adhesive layer 222 can be between approximately 100 μm and approximately 150 μm. Figure 15 The workpiece shown can be referred to as structure 226.

[0039] refer to Figure 1 and Figure 16Method 100 includes a frame 122, at which a filter structure 230 is formed on region R1”' of a fourth substrate 202D. The fourth substrate 202D may be formed of quartz, fused silica, sapphire, or other suitable material that is transparent to the wavelength of the light of interest. The fourth substrate 202D also includes a plurality (e.g., two) of alignment marks 228. It is understood that the arrangement (e.g., position, shape, size) and number of alignment marks 228 are merely examples. In embodiments, the top view dimensions and shape of the fourth substrate 202D are similar to those of the third substrate 202C. That is, when the fourth substrate 202D is aligned with the third substrate 202C, the boundary and center line of the fourth substrate 202D are substantially aligned with the boundary and center line of the third substrate 202C. In the embodiment, the positional relationship between region R1”' of the fourth substrate 202D and the alignment mark 228 corresponds to the positional relationship between the first region R1” of the third substrate 202C and the alignment mark 218, such that when the fourth substrate 202D is aligned with the third substrate 202C, region R1”' of the fourth substrate 202D will be aligned with the first region R1” of the third substrate 202C.

[0040] Forming the filter structure 230 may include depositing and patterning a fourth material layer on the fourth substrate 202D to form the filter structure 230 directly above region R1”' of the fourth substrate 202D. The fourth material layer may include a dye-based (or pigment-based) polymer for filtering out a specific frequency band (e.g., a desired wavelength of light). Other suitable materials are also possible. In some embodiments, the filter structure 230 may include several filters.

[0041] refer to Figure 17 After forming the filter structure 230 directly above region R1”' of the fourth substrate 202D, a fourth adhesive layer 232 is formed on the fourth substrate 202D. In an embodiment, the fourth adhesive layer 232 is formed on and around the filter structure 230. The fourth adhesive layer 232 may comprise any suitable material having a low light absorption coefficient (or absorptivity), such as a benzocyclobutene (BCB) polymer, and may be deposited using any suitable method.

[0042] refer to Figure 1 and Figure 18Method 100 includes block 124, at which a fourth substrate 202D is aligned with a third substrate 202C. As described above, the fourth substrate 202D includes alignment marks 228 and the third substrate 202C includes alignment marks 218. The fourth substrate 202D can be moved laterally until each alignment mark 228 in the fourth substrate 202D is aligned with a corresponding alignment mark 218 in the third substrate 202C. That is, a wafer-level alignment process is performed to align the fourth substrate 202D with the third substrate 202C. Therefore, high alignment accuracy can be obtained. Once the fourth substrate 202D and the third substrate 202C are aligned, region R1”' of the fourth substrate 202D is aligned with the first region R1” of the third substrate 202C. In other words, the filter structure 230 is disposed directly below the first lens structure 220a. After alignment between the fourth substrate 202D and the third substrate 202C, the distance between the center line of the filter structure 230 and the center line of the first lens structure 220a can be less than 10 μm. In one embodiment, there is essentially no offset between the center line of the filter structure 230 and the center line of the first lens structure 220a.

[0043] refer to Figure 1 and Figure 18 Method 100 includes block 126, at which a fourth substrate 202D is bonded to a third substrate 202C. After the fourth substrate 202D and the third substrate 202C are aligned, a fourth adhesive layer 232 directly faces the bottom surface of the third substrate 202C. The fourth substrate 202D can be moved toward the third substrate 202C until the fourth adhesive layer 232 bonds the fourth substrate 202D to the bottom surface of the third substrate 202C. In some embodiments, the fourth substrate 202D is bonded to the third substrate 202C by a thermoforming bonding process or other suitable bonding process. After the fourth substrate 202D is bonded to the third substrate 202C, Figure 18 In the illustrated embodiment, a first lens structure 220a is formed directly above a filter structure 230, which is disposed directly above region R1”' of the fourth substrate 202D. A beam splitter 208 is formed directly above a second lens structure 220b, which is formed directly above region R2”' of the fourth substrate 202D. After the bonding process, a thinning process (e.g., mechanical polishing and / or chemical thinning) can be performed to thin the fourth substrate 202D from the back side. Figure 18 The workpiece shown can be referred to as workpiece 200.

[0044] refer to Figure 1 and 19Method 100 includes block 128, at which a workpiece 200' is provided. In an embodiment, workpiece 200' includes a package substrate 202E. The package substrate 202E may be a printed circuit board (PCB) or any other suitable substrate. Workpiece 200' also includes an image sensor 236 formed directly above a first region A10 of the package substrate 202E. In some embodiments, an adhesive layer (not shown) may be used to mount the image sensor 236 to the package substrate 202E. The image sensor 236 is electrically coupled to the package substrate 202E using bonding wires 237a and metal pads 237b. Workpiece 200' also includes a vertical-cavity surface-emitting laser (VCSEL) 238 formed directly above a second region A20 of the package substrate 202E. In some embodiments, the adhesive layer may be used to attach the VCSEL 238 to the package substrate 202E. The VCSEL 238 is electrically coupled to the package substrate 202E using bonding wires 239a and metal pads 239b. The packaging substrate 202E includes alignment marks 234. The positional relationship between the first region A10 of the packaging substrate 202E, the image sensor 236, and the alignment marks 234 can be used as a reference to determine the configuration of the first lens structure 220a and the filter structure 230. The positional relationship between the second region A20 of the packaging substrate 202E, the VCSEL 238, and the alignment marks 234 can be used as a reference to determine the configuration of the second lens structure 220b and the beam splitter 208. Therefore, when the alignment marks 234 are aligned with alignment marks 203, 205, 218, and 228, the first lens structure 220a and the filter structure 230 are both positioned directly above the image sensor 236, and the beam splitter 208 and the second lens structure 220b are both positioned directly above the VCSEL 238.

[0045] The workpiece 200' also includes a fifth adhesive layer 242 formed on and around the packaging substrate 202E. For example, the fifth adhesive layer 242 is formed on and around the image sensor 236 and VCSEL 238. The fifth adhesive layer 242 may comprise any suitable material having a low light absorption coefficient (or absorptivity), such as a benzocyclobutene (BCB) polymer, and may be deposited using any suitable method.

[0046] refer to Figure 1 and Figure 20Method 100 includes block 130, at which a package substrate 202E is aligned with a fourth substrate 202D. As described above, the package substrate 202E includes alignment marks 234 and the fourth substrate 202D includes alignment marks 228. The package substrate 202E can be moved laterally until each alignment mark 234 in the package substrate 202E is aligned with a corresponding alignment mark 228 in the fourth substrate 202D. That is, a wafer-level alignment process is performed to align the package substrate 202E with the fourth substrate 202D, thereby achieving high alignment accuracy. Once the package substrate 202E and the fourth substrate 202D are aligned, a first region A10 of the package substrate 202E is aligned with a first region R1”' of the fourth substrate 202D, and a second region A20 of the package substrate 202E is aligned with a second region R2”' of the fourth substrate 202D. In one embodiment, after the packaging substrate 202E and the fourth substrate 202D are aligned, the distance between the center line of the image sensor 236 and the center line of the filter structure 230 can be less than 10 μm, and the distance between the center line of the VCSEL 238 and the center line of the second lens structure 220b can be less than 10 μm.

[0047] refer to Figure 1 and Figure 20 Method 100 includes a block 132, at which an encapsulation substrate 202E is bonded to a fourth substrate 202D via a fifth adhesive layer 242. After the encapsulation substrate 202E and the fourth substrate 202D are aligned, the fifth adhesive layer 242 directly faces the bottom surface of the fourth substrate 202D. The encapsulation substrate 202E can be moved toward the fourth substrate 202D until the fifth adhesive layer 242 bonds the encapsulation substrate 202E to the bottom surface of the fourth substrate 202D, thereby forming a workpiece 200". In some embodiments, the encapsulation substrate 202E is bonded to the fourth substrate 202D by a thermoforming bonding process or other suitable bonding process. The workpiece 200" includes a first lens structure 220a formed directly above a filter structure 230, a filter structure 230 disposed directly above an image sensor 236, a beam splitter 208 formed directly above a second lens structure 220b, and a second lens structure 220b formed directly above a VCSEL 238.

[0048] refer to Figure 1 and Figure 21Method 100 includes block 134, where further processing is performed. This further processing may include performing a monolithic process to cut along scribe lines or scribing channels using a cutting technique (e.g., mechanical cutting) to divide workpiece 200” into two or more individual optical modules, such as optical module 200A” and optical module 200B”. Since the first substrate 202A, second substrate 202B, third substrate 202C, and fourth substrate 202D are transparent substrates, in some embodiments, only one of these substrates 202A-202D is manufactured to have scribe lines or scribing channels.

[0049] In one embodiment, after monolithic fabrication, the optical module 200A” includes an image sensor 236 electrically coupled to a packaging substrate 202E using bonding wires 237a, a filter structure 230 disposed directly above the image sensor 236, and a first lens structure 220a formed directly above the filter structure 230 and the image sensor 236. In some embodiments, the optical module 200A” can be used to form an infrared (IR) camera. In one embodiment, the distance between the centerline of the filter structure 230 and the centerline of the image sensor 236 is less than 10 μm, and the distance between the centerline of the first lens structure 220a and the centerline of the image sensor 236 is less than 10 μm. The optical module 200A” also includes a first substrate 202A, an adhesive layer 214, and a second substrate 202B formed directly above the first lens structure 220a.

[0050] The optical module 200B” includes a VCSEL 238 electrically coupled to a packaging substrate 202E, a second lens structure 220b formed directly above the VCSEL 238, and a beam splitter 208 formed directly above both the second lens structure 220b and the VCSEL 238. In some embodiments, the optical module 200B” can be used to form a point projector. In one embodiment, the distance between the centerline of the second lens structure 220b and the centerline of the VCSEL 238 is less than 10 μm, and the distance between the centerline of the beam splitter 208 and the centerline of the VCSEL 238 is less than 10 μm. Optical module 200B” also includes an adhesive layer 232 and a fourth substrate 202D vertically sandwiched between the second lens structure 220b and the VCSEL 238. In various embodiments, the cutting technique used in the monolithic process forms a straight cut. That is, the sidewalls 250 of optical module 200A” and 252 of optical module 200B” are substantially vertical. In other words, each of the first substrate 202A, second substrate 202B, third substrate 202C, fourth substrate 202D and packaging substrate 202E has a vertical sidewall, and these vertical sidewalls are aligned along the Z direction. Here, “substantially vertical” means that the angle formed between the sidewall and the top surface of the corresponding optical module is between 88° and 92°.

[0051] Reference Figure 2-21 In the embodiments described above, the workpiece 200” manufactured according to method 100 is diced to form an optical module 200A” and an optical module 200B”. However, method 100 can be used to form workpieces (e.g., workpiece 200”') that can be diced to form more optical modules. For example, a plurality of first lens structures 220a and a plurality of second lens structures are formed on a third substrate 202C, a plurality of filter structures are formed on a fourth substrate 202D, a plurality of beam splitters 208 are formed between a first wafer 202A and a second wafer 202B, and a plurality of image sensors 236 and a plurality of VCSELs 238 are mounted on a packaging substrate 202E. Operations (e.g., flipping, alignment, and bonding processes) can be performed on these wafers to form Figure 22 The workpiece shown is 200”’. Figure 22 In the embodiment shown, the workpiece 200”' includes multiple regions A1 for forming optical module 200A” and multiple regions A2 for forming optical module 200B”. The workpiece 200”' can then be cut to form multiple optical modules 200A” and multiple optical modules 200B”. Figure 22 The configuration of workpiece 200”' shown is merely an example and is not intended to be limiting.

[0052] Reference Figure 1-22In the embodiments described above, optical modules 200A” and 200B” with different structures are formed simultaneously. As described above, in addition to these optical elements (e.g., the first lens structure 220a, the filter structure 230, and the image sensor 236), optical module 200A” also includes a first substrate 202A, an adhesive layer 214, and a second substrate 202B formed directly above the first lens structure 220a; similarly, optical module 200B” also includes an adhesive layer 232 and a fourth substrate 202D vertically sandwiched between the second lens structure 220b and the VCSEL 238. For example, other methods are also possible to form more point projectors and more IR cameras while reducing the total thickness of optical modules 200A” and 200B”. Figure 23 A flowchart illustrating exemplary operations in an alternative method 300 for forming a plurality of first optical modules and a plurality of second optical modules according to an embodiment of the present disclosure is provided. Method 300 is described below in conjunction with... Figure 24-33 Describe it. Figure 24-33 It is a partial sectional view of a workpiece at different manufacturing stages according to an embodiment of method 300.

[0053] refer to Figure 23 and Figure 24 Method 300 includes block 302, at which a first workpiece 400A is provided. The first workpiece 400A includes a first substrate 402A. In an embodiment, the first substrate 402A includes a plurality of alignment marks (not shown). The first workpiece 400A also includes predetermined regions A1,…A1 formed on the first substrate 402A. N-1 A N The multiple lens structures 4041, ... 404 on top N-1 404 N N is an integer and not less than 3. For example, lens structure 4041 is formed on region A1 of the first substrate 402A, and lens structure 404... N-1 Region A formed on the first substrate 402A N-1 Above, and lens structure 404 N Region A formed on the first substrate 402A N Above. These lens structures 4041, ... 404 N-1 404 N They have substantially the same configuration (e.g., size, function). The first workpiece 400A also includes an adhesive layer 406 formed on the first substrate 402A. The first substrate 402A may be similar to the third substrate 202C, with each lens structure 4041, ... 404 having a substantially identical configuration (e.g., size, function). N-1 404 N It can be similar to the first lens structure 220a, and the adhesive layer 406 can be similar to the adhesive layer 222. For simplicity, repeated descriptions are omitted.

[0054] refer to Figure 23 and Figure 25 Method 300 includes block 304, at which a second workpiece 400B is provided. The second workpiece 400B includes a second substrate 402B having a plurality of alignment marks (not shown). The second workpiece 400B also includes predetermined regions B1, B2, ... B1 respectively formed on the second substrate 402B. N The above multiple filter structures 4081, 4082, ... 408 N In an embodiment, the number of filter structures formed on the second substrate 402B is the same as the number of lens structures formed on the first substrate 402A. In an embodiment, filter structures 4081, 4082, ... 408 are used to form filter structures thereon. N Areas B1, B2, ... B N Based on regions A1,…A N-1 A N The location is determined by the specified position. More specifically, when the first workpiece 400A is flipped and aligned between the first substrate 402A and the second substrate 402B, regions A1,…A N-1 A N They will be respectively with region B N ...B2, B1 alignment. These filter structures 4081, 4082, ... 408 N They have substantially the same configuration (e.g., size and function). The second workpiece 400B also includes an adhesive layer 410 formed on the second substrate 402B. The second substrate 402B may be similar to the fourth substrate 202D, with each filter structure 4081, 4082, ... 408 having a substantially identical configuration (e.g., size and function). N Similar to filter structure 230, adhesive layer 410 can be similar to adhesive layer 232, and for simplicity, repeated descriptions are omitted.

[0055] refer to Figure 23 and Figure 26 Method 300 includes frame 306, where the first workpiece 400A is flipped. For example... Figure 26 As shown, after the first workpiece 400A is flipped, the first substrate 402A is located on top and disposed on the lens structures 4041, ... 404. N-1 404 N Above. As the first workpiece 400A is flipped, frame 306 proceeds to wafer-level alignment of the first substrate 402A and the second substrate 402B. The alignment of the first substrate 402A and the second substrate 402B can be similar to the alignment of the first substrate 202A and the second substrate 202B. For example, the second substrate 402B can be moved laterally until each alignment mark of the second substrate 402B is aligned with the corresponding alignment mark of the first substrate 402A.

[0056] refer to Figure 23 and 26 Method 300 includes block 308, at which a first substrate 402A is bonded to a second substrate 402B. A first adhesive layer 406 and a second adhesive layer 410 can bond the first substrate 402A to the second substrate 402B, thereby forming a bonding structure 400'. After the first substrate 402A is bonded to the second substrate 402B, in Figure 26 In the illustrated embodiment, lens structure 4041 is formed on filter structure 408. N Directly above. In one embodiment, lens structures 4041, ... 404 N-1 404 N Each centerline of the first substrate 402A is substantially aligned with the corresponding centerline of the filter structure disposed below it. Each lens structure is vertically spaced from the corresponding filter structure by a first adhesive layer 406 and a second adhesive layer 410. After the first substrate 402A is bonded to the second substrate 402B, a thinning process can be performed to thin the first substrate 402A and the second substrate 402B from the back sides of the first and second substrates to reduce the total thickness of the bonding structure 400'. After the thinning process, the bottom surface of the second substrate 402B can be referred to as the bottom surface 402S.

[0057] In one embodiment, the first workpiece 400A is flipped and the first substrate 402A is bonded to the second substrate 402B. In some other embodiments, the configuration of the filter structure and lens structure, as well as the positions of predetermined areas of the first substrate 402A and the second substrate 402B, can be adjusted such that the first substrate 402A can be bonded to the second substrate 402B, similar to the reference embodiment. Figure 18 The description is as follows, without flipping the first workpiece 400A or the second workpiece 400B.

[0058] refer to Figure 23 and Figure 27 Method 300 includes block 310, where the bonding structure 400' is cut into N optical units 420. In embodiments, a cutting technique (e.g., mechanical cutting) can be used to cut the bonding structure 400' along scribe lines or scribe channels on the first substrate 402A and / or the second substrate 402B to cut the bonding structure 400' into N optical units 420. Each optical unit 420 includes a lens structure formed directly above the filter structure. In various embodiments, the cutting technique forms a straight cut. That is, the sidewalls of each optical unit 420 are substantially vertical. That is, each of the first substrate 402A and the second substrate 402B has vertical sidewalls, and these vertical sidewalls are aligned along the Y direction.

[0059] refer to Figure 23and Figure 28 Method 300 includes block 312, at which a third workpiece 400C is provided. The third workpiece 400C includes N beam splitters 4241, 4242, ..., 424 sandwiched between substrate 402C1 and third substrate 402C2. N Substrate 402C1 and third substrate 402C2 each include multiple alignment marks (not shown). N beam splitters 4241, 4242, ..., 424 N Predetermined regions C1, C2, ..., C1 formed on the third substrate 402C2 N Directly above. These beam splitters have substantially the same structure and configuration. Each beam splitter includes an upper part and a lower part, with the lower part spaced apart from the upper part by an adhesive structure 426. The adhesive structure 426 may include one or more adhesive layers and may be similar to adhesive layer 214. Beam splitters 4241, 4242, ..., 424 N The formation can be similar to that of a reference. Figure 11 The formation of the beam splitter 208 is described, but for simplicity, repeated descriptions are omitted.

[0060] refer to Figure 23 and Figure 29 Method 300 includes a block 314, at which a fourth workpiece 400D is provided. The fourth workpiece 400D includes multiple alignment marks (not shown) and multiple lens structures 4281, 4282, ... 428. N The fourth substrate 402D, the plurality of lens structures 4281, 4282, ... 428 N Predetermined regions D1, D2, ... D1 formed on the fourth substrate 402D N Above. In the embodiment, lens structures 4281, 4282, ... 428 are formed thereon. N Regions D1, D2, ... D N It is based on regions C1, C2, ..., C N The location is determined by the specified position. More specifically, when the third substrate 402C2 is aligned with the fourth substrate 402D, regions D1, D2, ... D N It will be associated with regions C1, C2, ..., C respectively. N Alignment. The fourth workpiece 400D also includes an adhesive layer 430 formed on the fourth substrate 402D. The fourth substrate 402D may be similar to the third substrate 202C, with lens structures 4281, 4282, ... 428... N Similar to the second lens structure 220b, the adhesive layer 430 can be similar to the adhesive layer 222. For simplicity, repeated descriptions are omitted.

[0061] refer to Figure 23 and Figure 30Method 300 includes block 316, where a third substrate 402C2 is aligned with a fourth substrate 402D. The alignment of the third substrate 402C2 and the fourth substrate 402D can be similar to the alignment of the third substrate 202C and the second substrate 202B.

[0062] refer to Figure 23 and Figure 30 Method 300 includes block 318, at which a third substrate 402C2 is bonded to a fourth substrate 402D. After the third substrate 402C2 and the fourth substrate 402D are aligned, a thermoforming bonding process can be performed to bond the third substrate 402C2 to the fourth substrate 402D, thereby forming a bonding structure 400". After the bonding structure 400" is formed, each beam splitter 4241, 4242, ..., 424 N Formed in those lens structures 4281, 4282, ... 428 N Directly above the corresponding lens structure. In one embodiment, lens structures 4281, 4282, ... 428 N Each centerline of the third substrate 402C2 is substantially aligned with the centerline of the corresponding beam splitter located below it. After the third substrate 402C2 is bonded to the fourth substrate 402D, a thinning process can be performed to thin the fourth substrate 402D from the back side.

[0063] refer to Figure 23 and Figure 31 Method 300 includes a block 320, at which the bonding structure 400” is cut into N optical units 440. The cutting of the bonding structure 400” can be similar to the cutting of the bonding structure 400’. Each optical unit 440 includes a beam splitter formed directly above the lens structure. In various embodiments, the sidewalls of each optical unit 440 are substantially vertical. That is, each substrate 402C1, 402C2, 402D has vertical sidewalls aligned along the Y direction.

[0064] refer to Figure 23 and Figure 32 Method 300 includes block 322, where a fifth workpiece 400E is provided. The fifth workpiece 400E can be similar to [reference needed]. Figure 19 For the sake of simplicity, repeated descriptions of workpiece 200' are omitted.

[0065] refer to Figure 23 and Figure 32Method 300 includes block 324, where optical unit 420 is mounted to image sensor 236 via adhesive layer 450, and optical unit 440 is mounted to vertical cavity surface emitting laser (VCSEL) 238 via adhesive layer 455, thereby forming a bonding structure 400”’. Adhesive layers 450 and 455 may be similar to adhesive layer 214a.

[0066] refer to Figure 23 and Figure 33 Method 300 includes a block 326, at which the bonding structure 400"' is cut to form a first optical module 460 and a second optical module 480. Since the optical elements for optical unit 420 and optical elements for optical unit 440 are formed separately, the first optical module 460 has a thickness reduced compared to the thickness of optical module 200A", and the second optical module 480 has a thickness reduced compared to the thickness of the optical module.

[0067] Reference Figure 1-33 In the embodiments described above, the image sensor 236 and VCSEL 238 are electrically coupled to the package substrate 202E via bonding lines (e.g., bonding lines 237a and 239a) and metal pads (e.g., metal pads 237b and 239b) before being bonded to other optical elements (beam splitters, lens structures, and / or filter structures). In some other embodiments, the image sensor 236 and VCSEL 238 may be electrically coupled to the package substrate 202E after being bonded to other optical elements. Figure 34 A flowchart depicts an alternative method 500 for forming a plurality of first optical modules according to an embodiment of the present disclosure. Method 500 combines... Figures 35-46 Describe, Figures 35-46 This is a partial cross-sectional view of a workpiece at different manufacturing stages according to an embodiment of method 500. More specifically, at the stage of forming the first bonding structure 400' ( Figure 26 After (as shown), the operation of method 500 is executed.

[0068] refer to Figure 34 and Figure 35 Method 500 includes a frame 502, where the first bonding structure 400' is flipped. (As...) Figure 35 As shown, the second substrate 402B is on top and disposed in the filter structures 4081, 4082, ... 408. N Above. The flipped bonding structure 400' can be called the first bonding structure 600.

[0069] refer to Figure 34 and Figure 36Method 500 includes a frame 504, at which portions of the second substrate 402B are recessed to form a plurality of recesses 602. In some embodiments, a mask film may be deposited on the bottom surface 402S of the second substrate 402B and then patterned by a photolithography process. The patterned mask film exposes regions A1,…A1 of the second substrate 402B that are not disposed on the first substrate 402A. N-1 A N The portion directly above. While using a patterned mask as an etching mask, an etching process is performed to recess a portion of the second substrate 402B exposed by the patterned mask to form a plurality of recesses 602. The patterned mask can then be selectively removed.

[0070] refer to Figure 34 and Figure 37 Method 500 includes a frame 506 at which an adhesive layer 604 is formed on the bottom surface 402S of the second substrate 402B. In an embodiment, the adhesive layer 604 is formed on the bottom surface 402S of the second substrate 402B, and not in the recess 602. The composition of the adhesive layer 604 may be similar to that of the adhesive layer 214a. After the adhesive layer 604 is formed, as... Figure 38 As shown, the first bonding structure 600 is flipped and the first substrate 402A is on top.

[0071] refer to Figure 34 and Figure 39 Method 500 includes block 508, at which a wafer 610 is provided. Wafer 610 includes a plurality of image sensors 6121, 6122, ... 612 formed in and on a semiconductor substrate. N (Not separately labeled). For simplicity, detailed structural features of the image sensor have been omitted. Wafer 610 also includes multiple metal pads 6141, 6142, ... 614. N and 6161, 6162, ... 616 N Used in image sensors 6121, 6122, ... 612 N External connections. In an embodiment, each image sensor is positioned between two corresponding metal pads. In some embodiments, wafer 610 may include multiple alignment marks.

[0072] refer to Figure 34 and Figure 40 Method 500 includes block 510, at which the second substrate 420B is aligned with the wafer 610. The alignment between the wafer 610 and the second substrate 402B can be similar to that described above. Figure 15 The alignment is described. After alignment between wafer 610 and the second substrate 420B, lens structures 4041, ... 404 are... N-1 404N Each of the filter structures 4081, 4082, ... 408 N Each of these is located in the image sensors 6121, 6122, ... 612 N Directly above the corresponding image sensor, and metal pads 6141, 6142, ... 614 N Each of them and its corresponding adjacent metal pads (e.g., 6161, 6162, ..., or 616) N It is positioned directly below the corresponding recess 612.

[0073] refer to Figure 34 and Figure 40 Method 500 includes a frame 512 at which a first bonding structure 600 is bonded to a wafer 610. After the second substrate 420B is aligned with the wafer 610, the first bonding structure 600 is bonded to the wafer 610 via an adhesive layer 604, thereby obtaining a second bonding structure 620. In an embodiment, the second bonding structure 620 includes metal pads 6141, 6142, ... 614 disposed in a recess 602. N and 6161, 6162, ..., 616 N Each lens structure (e.g., lens structure 4041, ... 404) N-1 or 404 N ) is set in the corresponding filter structure (e.g., filter structure 408) N Directly above, and corresponding filter structures (e.g., filter structures 4081, 4082, ..., or 408) N ) is set on the corresponding image sensor (e.g., image sensor 6121, 6122, ..., or 612) N Directly above ).

[0074] refer to Figure 34 and Figure 41 Method 500 includes block 514, at which a partial cutting technique or etching process is performed to remove some portions of the first bonding structure 600 to expose metal pads 6141, 6142, ... 614. N and metal pads 6161, 6162, ..., 616 N In one embodiment, a patterned mask film may be formed on the second bonding structure 620 and configured to expose the portion of the first bonding structure 600 located directly above the recess 602. While using the patterned mask film as an etching mask, an etching process is performed to remove those exposed portions of the first bonding structure 600, thereby exposing the metal pads 6141, 6142, ... 614. N and metal pads 6161, 6162, ..., 616 NThen the patterned mask can be selectively removed.

[0075] refer to Figure 34 and Figure 42 Method 500 includes a block 516, at which the second bonding structure 620 is cut into N optical units 630. The cutting of the second bonding structure 620 may be similar to the cutting of the bonding structure 400'. Each optical unit 630 includes an image sensor, a filter structure formed directly above the image sensor, and a lens structure formed directly above the filter structure.

[0076] refer to Figure 34 and Figure 43 Method 500 includes a block 518 at which one of the optical units 630 is mounted onto a packaging substrate 202E to form an optical module 640. The optical units 630 can be mounted to the packaging substrate 202E by any suitable method (e.g., via an adhesive layer (not shown)). In some embodiments, the optical module 640 can be implemented to form an IR camera. Similar operations can be performed to form a point projector including a VCSEL, a beam splitter, and a lens structure.

[0077] refer to Figure 34 and Figure 43 Method 500 includes block 520, where an image sensor of the mounted optical module 640 is wired to a package substrate 202E. In an embodiment, the image sensor is electrically connected to the package substrate 202E via bonding wire 237a and metal pads (e.g., metal pads 6141 and 6161). Other methods may be used to achieve the electrical connection between the image sensor and the package substrate 202E. For example, in... Figures 44-46 In the embodiment shown, a substrate via (TSV) (not shown separately) and a connector can be used to enable electrical connection between the image sensor and the package substrate 202E.

[0078] Figure 44 The workpiece 650 is depicted, which includes a first bonding structure 600 bonded to the wafer 660 via an adhesive layer 670. Figure 35 (As shown in the diagram). Workpiece 650 can be similar to the second bonding structure 620, except that instead of having metal pads, wafer 660 includes a TSV (not shown) and a plurality of connectors 665 formed therein, such as ball grid array (“BGA”) balls or bumps formed beneath the bottom surface of wafer 660. Reference Figure 45 The workpiece 650 is cut into N optical units 680. Each optical unit 680 includes an image sensor, a filter structure formed directly above the image sensor, and a lens structure formed directly above the filter structure. Each optical unit 680 has a vertical sidewall. (Reference) Figure 46After forming optical units 680, one of the optical units 680 can be mounted and electrically coupled to the packaging substrate 202E via connector 665, thereby forming an optical module 690. In some embodiments, the optical module 690 can be used to form an IR camera. Similar operations can be performed to form other types of optical modules (e.g., optical module 480 can be used to form a dot projector).

[0079] The embodiments of this disclosure offer several advantages. For example, the methods of this disclosure include using wafer-level alignment and bonding processes to facilitate the formation of multiple optical modules. These optical modules may have the same or different structures and functions. For example, some optical modules can be implemented to form an IR camera, and some optical modules can be implemented to form a dot projector. These wafer-level alignments used to form the optical modules are generally beneficial due to increased productivity, reduced associated costs, and improved quality. By fabricating these optical elements using semiconductor-comparable processes, optical modules with reduced dimensions can be obtained. The methods of this disclosure can be readily applied to form other types of optical modules comprising vertically stacked optical elements.

[0080] This disclosure provides many different embodiments. This document discloses semiconductor structures and methods for manufacturing the same. In one exemplary aspect, this disclosure relates to a method. The method includes: forming a plurality of first optical elements on a first wafer; forming a plurality of second optical elements on a second wafer; aligning the first wafer and the second wafer, wherein, after alignment, each of the plurality of first optical elements vertically overlaps with a corresponding second optical element among the plurality of second optical elements; bonding the first wafer and the second wafer after alignment to obtain a first bonding structure; forming a plurality of third optical elements on a third wafer; aligning the second wafer of the first bonding structure with the third wafer, wherein, after alignment, each of the plurality of second optical elements vertically overlaps with a corresponding third optical element among the plurality of third optical elements; and bonding the second wafer of the first bonding structure to the third wafer after alignment to obtain a second bonding structure.

[0081] In some embodiments, each of the plurality of first optical elements may include a beam splitter, each of the plurality of second optical elements may include a lens structure, and each of the plurality of third optical elements may include a vertical-cavity surface-emitting laser (VCSEL). In some embodiments, each of the plurality of first optical elements may include a lens structure, each of the plurality of second optical elements may include a filter, and each of the plurality of third optical elements may include an image sensor. In some embodiments, each lens structure may include a plurality of lenses. In some embodiments, the method may include forming a plurality of fourth optical elements on a first wafer, wherein the plurality of fourth optical elements are of the same type as the plurality of first optical elements, and forming a plurality of fifth optical elements on a third wafer, wherein the plurality of fifth optical elements are of a different type than the plurality of third optical elements. After obtaining the second bonding structure, each of the plurality of fourth optical elements may vertically overlap with a corresponding fifth optical element among the plurality of fifth optical elements. In some embodiments, the method may include providing a fourth wafer and a fifth wafer, forming an upper portion of a plurality of sixth optical elements on the fourth wafer, forming a lower portion of a plurality of sixth optical elements on the fifth wafer, flipping the fourth wafer, aligning the fourth wafer with the fifth wafer after flipping, and bonding the fourth wafer with the fifth wafer after alignment, thereby obtaining a third bonding structure including a plurality of sixth optical elements. After the fourth wafer and the fifth wafer are aligned and bonded, each upper portion of the upper portion and the corresponding lower portion of the lower portion can form a corresponding optical element among the plurality of sixth optical elements. In some embodiments, the method may further include aligning the fifth wafer with a first wafer, wherein after aligning the fifth wafer with the first wafer, each of the plurality of sixth optical elements vertically overlaps with a corresponding first optical element among the plurality of first optical elements, and after aligning the fifth wafer with the first wafer, bonding the fifth wafer with the first wafer, thereby obtaining a fourth bonding structure. In some embodiments, the method may further include dicing the fourth bonding structure to form a plurality of first optical modules and a plurality of second optical modules. In some embodiments, each of the plurality of first optical modules may include one of a plurality of first optical elements, one of a plurality of second optical elements, and one of a plurality of third optical elements, and each of the plurality of second optical modules may include one of a plurality of fourth optical elements, one of a plurality of fifth optical elements, and one of a plurality of sixth optical elements. In some embodiments, each of the plurality of first optical modules and each of the plurality of second optical modules may include a vertical sidewall.

[0082] In another exemplary aspect, this disclosure relates to a method. The method includes forming a plurality of first optical elements on a first wafer, forming a plurality of second optical elements on a second wafer, forming a plurality of third optical elements on a third wafer, aligning the first wafer with the second wafer after forming the plurality of first optical elements and the plurality of second optical elements, bonding the first wafer with the second wafer after aligning the first wafer with the second wafer, aligning the second wafer with the third wafer after forming the plurality of third optical elements, bonding the first wafer with the second wafer with the third wafer after aligning the second wafer with the third wafer to obtain a bonding structure, dicing the bonding structure to form a plurality of first optical modules, wherein each of the plurality of first optical modules includes one of the plurality of first optical elements, one of the plurality of second optical elements, and one of the plurality of third optical elements, and wherein each of the plurality of first optical modules includes a vertical sidewall.

[0083] In some embodiments, bonding the first wafer to the second wafer may include applying an adhesive layer over a plurality of second optical elements, pressing the adhesive layer against the bottom surface of the first wafer, and performing a heating process to cure the adhesive layer. In some embodiments, the method may further include flipping the first wafer before aligning the first wafer and the second wafer. In some embodiments, bonding the first wafer to the second wafer may include applying a first adhesive layer over a plurality of first optical elements and a second adhesive layer over a plurality of second optical elements before flipping the first wafer, pressing the first adhesive layer against the second adhesive layer after the first wafer is flipped and aligned, and performing a heating process to cure the first adhesive layer and the second adhesive layer. In some embodiments, the method may further include thinning the first wafer and the second wafer after bonding the first wafer and the second wafer. In some embodiments, the method may further include providing a workpiece comprising a fourth wafer, a fifth wafer, and a plurality of fourth optical elements vertically sandwiched between the fourth wafer and the fifth wafer, wherein the upper portion of each of the plurality of fourth optical elements may be spaced apart from a corresponding lower portion of each of the plurality of fourth optical elements by an adhesive layer.

[0084] In another exemplary aspect, this disclosure relates to an optical module structure. The optical module includes a first substrate, an image sensor disposed on and electrically coupled to the first substrate, a first adhesive layer disposed on the image sensor, a second substrate disposed on the image sensor and attached to the image sensor via the first adhesive layer, a filter disposed on the second substrate and positioned directly above the image sensor, a third substrate disposed on the filter and attached to the filter via a second adhesive layer, and a lens structure disposed on the third substrate and positioned directly above the image sensor and the filter, wherein the sidewall surfaces of the first substrate are aligned with the sidewall surfaces of the second substrate.

[0085] In some embodiments, the sidewall surface of the first substrate may be a substantially vertical sidewall surface. In some embodiments, the filter may be spaced apart from the image sensor via a first adhesive layer and a second substrate. In some embodiments, the first substrate may include a printed circuit board, and the image sensor may be electrically coupled to the first substrate.

[0086] The foregoing has outlined features of several embodiments to enable those skilled in the art to better understand various aspects of this disclosure. Those skilled in the art should understand that they can readily use this disclosure as a basis for designing or modifying other processes and structures for performing the same purposes and / or achieving the same advantages of the embodiments described herein. Those skilled in the art should also recognize that such equivalent structures do not depart from the spirit and scope of this disclosure, and that various alterations, substitutions, and changes can be made to this document without departing from its spirit and scope.

[0087] Example 1. A method for forming a semiconductor structure, comprising:

[0088] Multiple first optical elements are formed on the first wafer;

[0089] Multiple second optical elements are formed on the second wafer;

[0090] Align the first wafer with the second wafer, wherein, after aligning the first wafer with the second wafer, each of the plurality of first optical elements vertically overlaps with the corresponding second optical element of the plurality of second optical elements;

[0091] After aligning the first wafer with the second wafer, the first wafer and the second wafer are bonded together to obtain the first bonding structure;

[0092] Multiple third optical elements are formed on the third wafer;

[0093] Align the second wafer of the first bonding structure with the third wafer, wherein, after aligning the second wafer with the third wafer, each of the plurality of second optical elements vertically overlaps with its corresponding third optical element among the plurality of third optical elements; and

[0094] After aligning the second wafer with the third wafer, the second wafer of the first bonding structure is bonded to the third wafer to obtain the second bonding structure.

[0095] Example 2. The method according to Example 1, wherein each of the plurality of first optical elements includes a beam splitter, each of the plurality of second optical elements includes a lens structure, and each of the plurality of third optical elements includes a vertical-cavity surface-emitting laser (VCSEL).

[0096] Example 3. The method according to Example 1, wherein each of the plurality of first optical elements includes a lens structure, each of the plurality of second optical elements includes a filter, and each of the plurality of third optical elements includes an image sensor.

[0097] Example 4. The method described in Example 3, wherein each lens structure comprises multiple lenses.

[0098] Example 5. The method described in Example 3 further includes:

[0099] A plurality of fourth optical elements are formed on the first wafer, wherein the type of the plurality of fourth optical elements is the same as the type of the plurality of first optical elements; and

[0100] A plurality of fifth optical elements are formed on the third wafer, wherein the type of the plurality of fifth optical elements is different from the type of the plurality of third optical elements.

[0101] Wherein, after obtaining the second bonding structure, each of the plurality of fourth optical elements vertically overlaps with the corresponding fifth optical element among the plurality of fifth optical elements.

[0102] Example 6. The method described in Example 5 further includes:

[0103] Provide the fourth and fifth wafers;

[0104] The upper part of a plurality of sixth optical elements is formed on the fourth wafer;

[0105] The lower portion of the plurality of sixth optical elements is formed on the fifth wafer;

[0106] Flip the fourth wafer;

[0107] After the fourth wafer is flipped, the fourth wafer is aligned with the fifth wafer; and

[0108] After the fourth wafer and the fifth wafer are aligned, the fourth wafer and the fifth wafer are bonded together to obtain a third bonding structure including the plurality of sixth optical elements.

[0109] Wherein, after the alignment and bonding of the fourth wafer and the fifth wafer, each of the upper portions and the corresponding lower portions of the lower portions form the corresponding optical elements of the plurality of sixth optical elements.

[0110] Example 7. The method described in Example 6 further includes:

[0111] Align the fifth wafer with the first wafer, wherein, after the fifth wafer is aligned with the first wafer, each of the plurality of sixth optical elements vertically overlaps with its corresponding first optical element among the plurality of first optical elements; and

[0112] After the fifth wafer is aligned with the first wafer, the fifth wafer is bonded to the first wafer to obtain the fourth bonding structure.

[0113] Example 8. The method described in Example 7 further includes:

[0114] The fourth bonding structure is cut to form a plurality of first optical modules and a plurality of second optical modules.

[0115] Example 9. According to the method described in Example 8,

[0116] Each of the plurality of first optical modules includes one of the plurality of first optical elements, one of the plurality of second optical elements, and one of the plurality of third optical elements.

[0117] Each of the plurality of second optical modules includes one of the plurality of fourth optical elements, one of the plurality of fifth optical elements, and one of the plurality of six optical elements.

[0118] Example 10. The method according to Example 8, wherein each of the plurality of first optical modules and each of the plurality of second optical modules includes a vertical sidewall.

[0119] Example 11. A method for forming a semiconductor structure, comprising:

[0120] Multiple first optical elements are formed on the first wafer;

[0121] Multiple second optical elements are formed on the second wafer;

[0122] Multiple third optical elements are formed on the third wafer;

[0123] After forming the plurality of first optical elements and the plurality of second optical elements, the first wafer and the second wafer are aligned;

[0124] After the first wafer and the second wafer are aligned, the first wafer and the second wafer are bonded together;

[0125] After forming the plurality of third optical elements, the second wafer is aligned with the third wafer;

[0126] After the second wafer and the third wafer are aligned, the first wafer and the second wafer are bonded to the third wafer to obtain a bonded structure; and

[0127] The bonding structure is cut to form a plurality of first optical modules, wherein each of the plurality of first optical modules includes one of the plurality of first optical elements, one of the plurality of second optical elements and one of the plurality of third optical elements, and wherein each of the plurality of first optical modules includes a vertical sidewall.

[0128] Example 12. The method according to Example 11, wherein the bonding of the first wafer to the second wafer includes:

[0129] An adhesive layer is applied over the plurality of second optical elements;

[0130] Pressing the adhesive layer against the bottom surface of the first wafer; and

[0131] A heating process is performed to cure the adhesive layer.

[0132] Example 13. The method described in Example 11 further includes:

[0133] Before aligning the first wafer with the second wafer, flip the first wafer.

[0134] Example 14. The method according to Example 13, wherein the bonding of the first wafer to the second wafer includes:

[0135] Before the first wafer is flipped, a first adhesive layer is applied over the plurality of first optical elements;

[0136] A second adhesive layer is applied over the plurality of second optical elements;

[0137] After the first wafer is flipped and after the first wafer is aligned with the second wafer,

[0138] Pressing the first adhesive layer against the second adhesive layer; and

[0139] A heating process is performed to cure the first adhesive layer and the second adhesive layer.

[0140] Example 15. The method described in Example 11 further includes:

[0141] After the first wafer and the second wafer are bonded, the first wafer and the second wafer are thinned.

[0142] Example 16. The method according to Example 11 further includes:

[0143] A workpiece is provided, the workpiece comprising a fourth wafer, a fifth wafer, and a plurality of fourth optical elements vertically sandwiched between the fourth wafer and the fifth wafer.

[0144] The upper part of each of the plurality of fourth optical elements is spaced apart from the corresponding lower part of each of the plurality of fourth optical elements by an adhesive layer.

[0145] Example 17. An optical module comprising:

[0146] First substrate;

[0147] An image sensor is disposed on the first substrate and electrically coupled to the first substrate;

[0148] A first adhesive layer is disposed on the image sensor;

[0149] A second substrate is disposed on the image sensor and attached to the image sensor through the first adhesive layer;

[0150] A filter is disposed on the second substrate and directly above the image sensor;

[0151] A third substrate is disposed on the filter and attached to the filter via a second adhesive layer; and

[0152] A lens structure is disposed on the third substrate and directly above the image sensor and the filter.

[0153] Wherein, the sidewall surface of the first substrate is aligned with the sidewall surface of the second substrate.

[0154] Example 18. The optical module according to Example 17, wherein the sidewall surface of the first substrate is a substantially vertical sidewall surface.

[0155] Example 19. An optical module according to Example 17, wherein the filter is spaced apart from the image sensor by the first adhesive layer and the second substrate.

[0156] Example 20. An optical module according to Example 17, wherein the first substrate includes a printed circuit board, and the image sensor is electrically coupled to the first substrate.

Claims

1. A method for forming a semiconductor structure, comprising: Multiple first optical elements are formed on the first wafer; Multiple second optical elements are formed on the second wafer; Align the first wafer with the second wafer, wherein, after aligning the first wafer with the second wafer, each of the plurality of first optical elements vertically overlaps with the corresponding second optical element of the plurality of second optical elements; After aligning the first wafer with the second wafer, the first wafer and the second wafer are bonded together to obtain the first bonding structure; Multiple third optical elements are formed on the third wafer; Align the second wafer of the first bonding structure with the third wafer, wherein, after aligning the second wafer with the third wafer, each of the plurality of second optical elements vertically overlaps with its corresponding third optical element among the plurality of third optical elements; and After aligning the second wafer with the third wafer, the second wafer of the first bonding structure is bonded to the third wafer, thereby obtaining the second bonding structure. The method further includes: Provide the fourth and fifth wafers; The upper part of a plurality of sixth optical elements is formed on the fourth wafer; The lower portion of the plurality of sixth optical elements is formed on the fifth wafer; Flip the fourth wafer; After the fourth wafer is flipped, the fourth wafer is aligned with the fifth wafer; and After the fourth wafer and the fifth wafer are aligned, the fourth wafer and the fifth wafer are bonded together to obtain a third bonding structure including the plurality of sixth optical elements. Wherein, after the alignment and bonding of the fourth wafer and the fifth wafer, each of the upper portions and the corresponding lower portions of the lower portions form the corresponding optical elements of the plurality of sixth optical elements.

2. The method according to claim 1, wherein, Each of the plurality of first optical elements includes a beam splitter, each of the plurality of second optical elements includes a lens structure, and each of the plurality of third optical elements includes a vertical-cavity surface-emitting laser (VCSEL).

3. The method according to claim 1, wherein, Each of the plurality of first optical elements includes a lens structure, each of the plurality of second optical elements includes a filter, and each of the plurality of third optical elements includes an image sensor.

4. The method according to claim 3, wherein, Each lens structure includes multiple lenses.

5. The method according to claim 3, further comprising: A plurality of fourth optical elements are formed on the first wafer, wherein the type of the plurality of fourth optical elements is the same as the type of the plurality of first optical elements; and A plurality of fifth optical elements are formed on the third wafer, wherein the type of the plurality of fifth optical elements is different from the type of the plurality of third optical elements. Wherein, after obtaining the second bonding structure, each of the plurality of fourth optical elements vertically overlaps with the corresponding fifth optical element among the plurality of fifth optical elements.

6. The method according to claim 5, further comprising: Align the fifth wafer with the first wafer, wherein, after the fifth wafer is aligned with the first wafer, each of the plurality of sixth optical elements vertically overlaps with its corresponding first optical element among the plurality of first optical elements; and After the fifth wafer is aligned with the first wafer, the fifth wafer is bonded to the first wafer to obtain the fourth bonding structure.

7. The method according to claim 6, further comprising: The fourth bonding structure is cut to form a plurality of first optical modules and a plurality of second optical modules.

8. The method according to claim 7, in, Each of the plurality of first optical modules includes one of the plurality of first optical elements, one of the plurality of second optical elements, and one of the plurality of third optical elements, and Each of the plurality of second optical modules includes one of the plurality of fourth optical elements, one of the plurality of fifth optical elements, and one of the plurality of sixth optical elements.

9. The method according to claim 7, wherein, Each of the plurality of first optical modules and each of the plurality of second optical modules includes a vertical sidewall.

10. A method for forming a semiconductor structure, comprising: Multiple first optical elements are formed on the first wafer; Multiple second optical elements are formed on the second wafer; Multiple third optical elements are formed on the third wafer; After forming the plurality of first optical elements and the plurality of second optical elements, the first wafer and the second wafer are aligned; After the first wafer and the second wafer are aligned, the first wafer and the second wafer are bonded together; After forming the plurality of third optical elements, the second wafer is aligned with the third wafer; After the second wafer and the third wafer are aligned, the first wafer and the second wafer are bonded to the third wafer to obtain a bonded structure; as well as The bonding structure is cut to form a plurality of first optical modules, wherein each of the plurality of first optical modules includes one of the plurality of first optical elements, one of the plurality of second optical elements, and one of the plurality of third optical elements, and wherein each of the plurality of first optical modules includes a vertical sidewall. The method further includes: Provide the fourth and fifth wafers; The upper part of a plurality of fourth optical elements is formed on the fourth wafer; The lower portion of the plurality of fourth optical elements is formed on the fifth wafer; Flip the fourth wafer; After the fourth wafer is flipped, the fourth wafer is aligned with the fifth wafer; and After the fourth wafer and the fifth wafer are aligned, the fourth wafer and the fifth wafer are bonded together to obtain a second bonding structure including the plurality of fourth optical elements. Wherein, after the alignment and bonding of the fourth wafer and the fifth wafer, each of the upper portions and the corresponding lower portions of the lower portions form the corresponding optical elements of the plurality of fourth optical elements.

11. The method according to claim 10, wherein, The bonding between the first wafer and the second wafer includes: An adhesive layer is applied over the plurality of second optical elements; Pressing the adhesive layer against the bottom surface of the first wafer; and A heating process is performed to cure the adhesive layer.

12. The method of claim 10, further comprising: Before aligning the first wafer with the second wafer, flip the first wafer.

13. The method according to claim 12, wherein, The bonding between the first wafer and the second wafer includes: Before the first wafer is flipped, a first adhesive layer is applied over the plurality of first optical elements; A second adhesive layer is applied over the plurality of second optical elements; After the first wafer is flipped and after the first wafer is aligned with the second wafer, Pressing the first adhesive layer against the second adhesive layer; and A heating process is performed to cure the first adhesive layer and the second adhesive layer.

14. The method of claim 10, further comprising: After the first wafer and the second wafer are bonded, the first wafer and the second wafer are thinned.

15. An optical module, comprising: First substrate; An image sensor is disposed on the first substrate and electrically coupled to the first substrate; A first adhesive layer is disposed on the image sensor; A second substrate is disposed on the image sensor and attached to the image sensor through the first adhesive layer; A filter is disposed on the second substrate and directly above the image sensor; A third substrate is disposed on the filter and attached to the filter by a second adhesive layer; as well as A lens structure is disposed on the third substrate and directly above the image sensor and the filter. Wherein, the sidewall surface of the first substrate is aligned with the sidewall surface of the second substrate. The optical module further includes: A fourth substrate is disposed on the lens structure and attached to the lens structure through a third adhesive layer; The lower part of the beam splitter is disposed on the fourth substrate; A fourth adhesive layer is disposed on the lower part of the beam splitter; The upper part of the beam splitter is disposed above the fourth adhesive layer and directly above the lower part of the beam splitter; The fifth substrate is disposed on the upper part of the beam splitter.

16. The optical module according to claim 15, wherein, The sidewall surface of the first substrate is a substantially vertical sidewall surface.

17. The optical module according to claim 15, wherein, The filter is spaced apart from the image sensor by the first adhesive layer and the second substrate.

18. The optical module according to claim 15, wherein, The first substrate includes a printed circuit board, and the image sensor is electrically coupled to the first substrate.

Images