阅读说明：本技术 半导体结构及其形成方法 (Semiconductor structure and forming method thereof ) 是由 余振华 夏兴国 黄松辉 黄冠育 丁国强 侯上勇 吴集锡 于 2019-06-27 设计创作，主要内容包括：本发明的实施例提供了一种半导体结构,包括光子集成电路管芯、电子集成电路管芯、半导体坝和绝缘密封剂。光子集成电路管芯包括光学输入/输出部分和位于光学输入/输出部分附近的凹部,其中凹部适于横向插入至少一个光纤。电子集成电路管芯设置在光子集成电路管芯上方并且电连接至光子集成电路管芯。半导体坝设置在光子集成电路管芯上方。绝缘密封剂设置在光子集成电路管芯上方并且横向封装电子集成电路管芯和半导体坝。本发明的实施例还提供了其他的半导体结构以及形成方法。(Embodiments of the present invention provide a semiconductor structure comprising a photonic integrated circuit die, an electronic integrated circuit die, a semiconductor dam, and an insulating encapsulant. The photonic integrated circuit die includes an optical input/output portion and a recess located proximate the optical input/output portion, wherein the recess is adapted for lateral insertion of at least one optical fiber. An electronic integrated circuit die is disposed over and electrically connected to the photonic integrated circuit die. A semiconductor dam is disposed over the photonic integrated circuit die. An insulating encapsulant is disposed over the photonic integrated circuit die and laterally encapsulates the electronic integrated circuit die and the semiconductor dam. Embodiments of the invention also provide other semiconductor structures and methods of forming the same.)

1. A semiconductor structure, comprising:

a photonic integrated circuit die comprising an optical input/output portion and a recess located proximate to the optical input/output portion;

an electronic integrated circuit die disposed over and electrically connected to the photonic integrated circuit die;

a semiconductor dam disposed over the photonic integrated circuit die; and

an insulating encapsulant disposed over the photonic integrated circuit die, laterally encapsulating the electronic integrated circuit die, and in physical contact with the semiconductor dam.

2. The semiconductor structure of claim 1, wherein the electronic integrated circuit die is electrically connected to the photonic integrated circuit die by a plurality of micro-bumps.

3. The semiconductor structure of claim 1, wherein the semiconductor dam comprises a recess, and the recess is accessibly exposed by the recess of the semiconductor dam.

4. The semiconductor structure of claim 3, further comprising:

a protrusion disposed over the photonic integrated circuit die, wherein the protrusion is accessibly exposed by the recess of the semiconductor dam.

5. The semiconductor structure of claim 3, further comprising:

a glue layer located between the semiconductor dam and the photonic integrated circuit die.

6. The semiconductor structure of claim 1, further comprising at least one optical fiber located in the recess.

7. The semiconductor structure of claim 1, further comprising:

a circuit substrate, wherein the photonic integrated circuit die is disposed over and electrically connected to the circuit substrate.

8. The semiconductor structure of claim 7, further comprising:

a plurality of conductive bumps; and

an underfill disposed between the circuit substrate and the photonic integrated circuit die, wherein the photonic integrated circuit die is electrically connected to the circuit substrate through the conductive bumps, and the conductive bumps are encapsulated by the underfill.

9. A semiconductor structure, comprising:

a photonic integrated circuit die comprising an optical input/output portion and a fiber recess located proximate to the optical input/output portion;

an electronic integrated circuit die and a semiconductor dam disposed in a side-by-side manner over the photonic integrated circuit die, the electronic integrated circuit die being electrically connected to the photonic integrated circuit die;

an insulating encapsulant disposed over the photonic integrated circuit die, laterally encapsulating the electronic integrated circuit die, and in physical contact with multiple sides of the semiconductor dam, wherein side surfaces of the semiconductor dam are exposed accessible by the insulating encapsulant, and the semiconductor dam separates the fiber recess from the insulating encapsulant; and

at least one optical fiber located in the optical fiber recess.

10. A method of forming a semiconductor structure, comprising:

providing a photonic integrated circuit die comprising at least one optical input/output portion and at least one recess;

bonding an electronic integrated circuit die and a dummy die on the photonic integrated circuit die; and

removing a portion of the dummy die to form a semiconductor dam having a recess such that the at least one recess is exposed by the recess of the semiconductor dam.

Technical Field

Embodiments of the present invention relate to the field of semiconductors, and more particularly, to semiconductor structures and methods of forming the same.

Background

Optical transceiver modules are used in high-speed optical communication systems, which require high performance, tight packaging, and low power consumption. Optical transmission/reception functions are implemented in pluggable optical transceiver modules. Optical transceiver modules have a variety of international standard specifications in reaching communication speeds greater than 100 Gbps. Currently, the manufacturing process of compact optical transceiver modules is very complex and requires an increase in their yield.

Disclosure of Invention

According to an embodiment of the present invention, there is provided a semiconductor structure including: a photonic integrated circuit die comprising an optical input/output portion and a recess located proximate to the optical input/output portion; an electronic integrated circuit die disposed over and electrically connected to the photonic integrated circuit die; a semiconductor dam disposed over the photonic integrated circuit die; and an insulating encapsulant disposed over the photonic integrated circuit die, laterally encapsulating the electronic integrated circuit die, and in physical contact with the semiconductor dam.

According to an embodiment of the present invention, there is provided a semiconductor structure including: a photonic integrated circuit die comprising an optical input/output portion and a fiber recess located proximate to the optical input/output portion; an electronic integrated circuit die and a semiconductor dam disposed in a side-by-side manner over the photonic integrated circuit die, the electronic integrated circuit die being electrically connected to the photonic integrated circuit die; an insulating encapsulant disposed over the photonic integrated circuit die, laterally encapsulating the electronic integrated circuit die, and in physical contact with multiple sides of the semiconductor dam, wherein side surfaces of the semiconductor dam are exposed accessible by the insulating encapsulant, and the semiconductor dam separates the fiber recess from the insulating encapsulant; and at least one optical fiber in the optical fiber recess.

According to an embodiment of the present invention, there is provided a method of forming a semiconductor structure, including: providing a photonic integrated circuit die comprising at least one optical input/output portion and at least one recess; bonding an electronic integrated circuit die and a dummy die on the photonic integrated circuit die; and removing a portion of the dummy die to form a semiconductor dam having a recess such that the at least one recess is exposed by the recess of the semiconductor dam.

Drawings

The invention is best understood from the following detailed description when read with the accompanying drawing figures. It should be emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various elements may be arbitrarily increased or reduced for clarity of discussion.

Fig. 1A-1C schematically illustrate a process flow for fabricating a dummy die according to some embodiments of the invention.

Fig. 2 schematically illustrates a perspective view of a single dummy die, in accordance with some embodiments of the present invention.

Figures 3A-3K schematically illustrate a process flow for fabricating a chip on wafer on substrate (CoWoS) package according to some embodiments of the present invention.

Fig. 4 schematically illustrates a perspective view of the interposer shown in fig. 3A and a single dummy die shown in fig. 2, in accordance with some embodiments of the present invention.

Figure 5 schematically illustrates a top view of the CoWoS package shown in figure 3K, according to some embodiments of the invention.

Fig. 6 schematically illustrates a cross-sectional view along line II-II' shown in fig. 5, according to some embodiments of the invention.

Figures 7 and 8 schematically illustrate cross-sectional views of a CoWoS package according to various embodiments of the present invention.

Fig. 9-11 schematically illustrate top views of a CoWoS package according to various embodiments of the present invention.

Detailed Description

The following description provides many different embodiments, or examples, for implementing different features of the invention. Specific examples of components and arrangements are described below to simplify the present disclosure. Of course, these are merely examples and are not intended to be limiting. For example, the formation of a first feature over a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed between the first and second features, such that the first and second features are not in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

For ease of description, spatially relative positional terms such as "below …," "below …," "below," "above …," "upper," and the like may be used herein to describe one element or component's relationship to another (or other) element or component as illustrated in the figures. It will be understood that these spatially relative positional terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Fig. 1A-1C schematically illustrate a process flow for fabricating a dummy die according to some embodiments of the invention. Fig. 2 schematically illustrates a perspective view of a single dummy die, in accordance with some embodiments of the present invention. Figures 3A-3K schematically illustrate a process flow for fabricating a CoWoS package according to some embodiments of the invention. Fig. 4 schematically illustrates a perspective view of the interposer shown in fig. 3A and a single dummy die shown in fig. 2, in accordance with some embodiments of the present invention.

Referring to fig. 1A, a dummy semiconductor wafer W1 including a plurality of dummy dies 100 is provided. The dummy dies 100 in the dummy semiconductor wafer W1 are arranged in an array and physically connected to each other. The dummy semiconductor wafer W1 may be a silicon dummy wafer. In some embodiments, the dummy semiconductor wafer W1 may include a plurality of trenches TR (e.g., ring-shaped trenches) formed therein, the trenches TR being arranged in an array, and each dummy die 100 may include at least one trench TR, respectively. The trenches TR extend from the top surface of the dummy semiconductor wafer W1 down to the inside of the dummy semiconductor wafer W1. In some alternative embodiments, the dummy semiconductor wafer W1 may include a plurality of trenches TR (e.g., annular trenches) formed therein and a plurality of alignment grooves AR (e.g., L-shaped alignment grooves or cross-shaped alignment grooves), wherein the trenches TR are arranged in an array, the alignment grooves AR correspond to the arrangement of the trenches TR, and each dummy die 100 may include at least one trench TR and at least one alignment groove AR, respectively. The trenches TR and the alignment grooves AR extend from the top surface of the dummy semiconductor wafer W1 down to the inside of the dummy semiconductor wafer W1. For example, each alignment groove AR is located around a corner of one of the trenches TR, respectively.

As shown in fig. 1A, in some embodiments, the depth of the trench TR is greater than the alignment groove AR. For example, the depth of the trench TR may be in a range from about 50 to about 600 microns, which may be about 7 to about 80% of the thickness of the dummy semiconductor wafer W1, and the depth of the alignment groove AR may be in a range from about 30 to about 300 microns, which may be about 4 to about 40% of the thickness of the dummy semiconductor wafer W1. The trench TR and the alignment groove AR may be formed by etching or other suitable processes.

Referring to fig. 1B, after providing the dummy semiconductor wafer W1, a printing process is performed on the dummy semiconductor wafer W1 to form a plurality of wall structures WS in the trenches TR, a plurality of alignment marks AM in the alignment grooves AR and a plurality of protective coatings PC partially covering the top surface of the dummy semiconductor wafer W1. The wall structures WS and the alignment marks AM are embedded in the dummy semiconductor wafer W1, and the wall structures WS and the alignment marks AM are not covered by the protective coating PC. In some embodiments, the wall structure WS may be an annular wall structure, and the alignment mark AM may be an L-shaped alignment mark or a cross-shaped alignment mark. For example, the wall structure WS, the alignment mark AM, and the protective coating PC are formed by a three-dimensional (3D) printing process such that the thickness and volume of the wall structure WS, the alignment mark AM, and the protective coating PC may be different. The material of the wall structure WS, the alignment mark AM and the protective coating PC may comprise a polymer (e.g. polyimide, etc.). The wall structure WS may partially fill the trench TR to allow placement of the protrusion P (not shown in fig. 1B, but shown and described below with reference to fig. 3A) at least partially in the trench TR, the alignment mark AM may completely fill the alignment groove AR, and the protective coating PC may cover a portion of the top surface of the dummy semiconductor wafer W1, which portion is surrounded by the annular wall structure WS. Since the wall structures WS partially fill the trenches TR and do not protrude from the top surface of the dummy semiconductor wafer W1, the wall structures WS are not in direct contact with the protective coating PC. For example, the height of the wall structures WS may be in the range from about 50 microns to about 600 microns, which is about 7% to about 80% of the thickness of the dummy semiconductor wafer W1. In some embodiments, the top surfaces of the wall structures WS are lower than the top surfaces of the individual dummy dies 100a, and the difference in level between the surfaces of the wall structures WS and the top surfaces of the individual dummy dies 100a is in a range from about 3 microns to about 50 microns.

The cross-sectional view of the single dummy die 100a shown in fig. 1C is taken along the cross-sectional line L-L' shown in fig. 2. Referring to fig. 1C, a dummy semiconductor wafer W1 is attached to a sawing tape T, which is carried by a frame F. A separation process (e.g., a wafer sawing process) is then performed to separate the dummy semiconductor wafer W1, thereby obtaining a plurality of individual dummy dies 100 a.

As shown in fig. 1C and 2, the single dummy die 100a includes a trench TR, a wall structure WS partially filled in the trench TR, an alignment mark AM, and a protective coating PC. The trenches TR and the wall structures WS define a central region and a peripheral region of the single dummy die 100a, wherein a region surrounded by the wall structures WS may be referred to as the central region, and a region outside the wall structures WS may be referred to as the peripheral region. The wall structures WS and the alignment marks AM are embedded in a single dummy die 100 a. The wall structures WS and the alignment marks AM each extend from the top surface of the single dummy die 100a down to the interior of the single dummy die 100 a. The protective coating PC partially covers the top surface of the central region of the single dummy die 100 a. The wall structures WS and the alignment marks AM are not covered by the protective coating PC. The protective coating PC may cover a portion of the top surface of the individual dummy die 100a, which portion is surrounded by the annular wall structure WS. Since the wall structures WS partially fill the trenches TR and do not protrude from the top surfaces of the individual dummy dies 100a, the wall structures WS embedded in the individual dummy dies 100a are not in direct contact with the protective coating PC. For example, the height of the wall structures WS may be in a range from about 50 microns to about 600 microns, which is about 7% to about 80% of the thickness of a single dummy die 100 a. In some alternative embodiments, a single dummy die 100a may not include alignment marks AM.

Referring to fig. 3A, an interposer wafer INT including a plurality of photonic integrated circuit dies 200 is provided. The photonic integrated circuit dies 200 in the interposer wafer INT are arranged in an array and physically connected to each other. Each photonic integrated circuit die 200 may include an electrical joint portion 200a, at least one optical input/output portion 200b configured to transmit and receive optical signals, and at least one recess 200c located proximate to the at least one optical input/output portion 200b, respectively. For example, the optical signal as described above is pulsed light, a combination of light and Continuous Wave (CW), or the like. In some embodiments, the electrical bonding portion 200a of the photonic integrated circuit die 200 may include structures to form semiconductor vias (TSVs, described below with reference to fig. 3G), semiconductor structures (e.g., transistors, capacitors, etc.), wires, or other conductors for electrical connection, and the optical input/output portion 200b of the photonic integrated circuit die 200 may include semiconductor devices and optical devices for processing optical signals. For example, the semiconductor device formed in the optical input/output section 200b may include a transistor, a capacitor, a photodiode, or a combination thereof, and the optical device formed in the optical input/output section 200b may include an edge coupler, a modulator, a waveguide, a filter, or a combination thereof. AS shown in fig. 3A, the interposer wafer INT may include a first active surface AS1 and a first back surface RS1 opposite the first active surface AS1, wherein the electrical engagement portions 200a, optical input/output portions 200b, and recesses 200c of the photonic integrated circuit die 200 are formed on the first active surface AS1 of the interposer wafer INT. In some embodiments, the recesses 200c formed on the first active surface AS1 of the interposer wafer INT may be V-shaped recesses (AS shown in fig. 4) formed by etching (e.g., stacking dielectric layers and passivation layers over the wafer INT, forming openings, lining the openings with a dielectric such AS silicon nitride, lining the openings, and wet etching the wafer INT by the lining before removing the layers) or other suitable processes. The number of recesses 200c formed on each photonic integrated circuit die 200 is not limiting in the present invention.

AS shown in fig. 3A, the interposer wafer INT may further include a plurality of conductive bumps B1 formed on the first active surface AS 1. In some embodiments, the conductive bumps B1 may be micro-bumps (e.g., solder bumps, copper bumps, or other metal bumps) formed on the first active surface AS1 of the interposer wafer INT. For example, multiple groups of conductive bumps B1 may be formed on the interposer wafer INT, and each group of conductive bumps B1 may be formed on one photonic integrated circuit die 200, respectively. In addition, the interposer wafer INT may further include a plurality of protrusions P formed on the first active surface AS 1. In some embodiments, the protrusions P are formed of the same material and serve as conductive bumps, but they may also be different. The protrusion P may be an annular protrusion, which surrounds the recess 200 c. The size (e.g., thickness and width), location, and shape of the protrusion P may be designed to correspond to the trench TR of the single dummy die 100a shown in fig. 2. For example, the height of the protrusions P may range from about 5 microns to about 50 microns.

Referring to fig. 3B, 3C, and 4, a plurality of glue layers G are formed on the first active surface AS1 of the interposer wafer INT. The single dummy die 100a is then picked and placed on the first active surface AS1 of the interposer wafer INT. A single dummy die 100a is attached on the first active surface AS1 of the interposer wafer INT by a glue layer G. The glue layer G may be a thermally cured polymer that is formed on the first active surface AS1 of the interposer wafer INT by a drop coating process or the like. The glue layer G may serve AS an adhesive for bonding the individual dummy die 100a and the first active surface AS1 of the interposer wafer INT together. The glue layer G may be laterally spaced from the protrusions P. In some alternative embodiments, the glue layer G may be bonded to the protrusions P. The thickness of the glue layer G may be less than the height of the protrusions P, as shown in fig. 3B. Furthermore, the distribution of the glue layers G may correspond to the peripheral area of the single dummy die 100a, such that the recesses 200c formed on the first active surface AS1 of the interposer wafer INT are not covered by the glue layers G.

After the single dummy die 100a is attached on the interposer wafer INT, the peripheral region of the single dummy die 100a is bonded to the interposer wafer INT by the glue layer G, and the middle region of the single dummy die 100a covers the recess 200 c. The protrusions P may extend towards the wall structures WS and protrude into the trenches TR of the individual dummy dies 100 a. In some embodiments, the protrusions P are in direct contact with the wall structures WS of the individual dummy die 100a, and the trenches TR of the individual dummy die 100a are completely or partially filled by the protrusions P and the wall structures WS. In some alternative embodiments, the protrusions P do not contact the wall structures WS of a single dummy die 100 a. The protrusions P and the trenches TR may facilitate alignment of the individual dummy die 100a with the interposer wafer INT.

After attaching the individual dummy die 100a on the interposer wafer INT, the protective coating PC of the individual dummy die 100a may cover and protect the recesses 200c of the interposer wafer INT from damage. As shown in fig. 3C, in some embodiments, the protective coating PC can be held a lateral distance from the protrusions P to help prevent the protective coating PC from interfering with the protrusions P. For example, the lateral distance between the protective coating PC and the protrusion P may be in the range from about 10 microns to about 100 microns. In some alternative embodiments, the protective coating PC may be in contact with the protrusion P. The thickness of the protective coating PC may be substantially equal to the thickness of the glue layer G. For example, the thickness of the protective coating PC and the glue layer G may range from about 100 microns to about 2000 microns. Additionally, the protective coating PC may be in contact with the first active surface AS1 of the interposer wafer INT, but not permanently bonded to the first active surface AS1 of the interposer wafer INT.

Referring to fig. 3C, a plurality of electronic integrated circuit dies 300 including conductive bumps B2 formed thereon are provided and mounted on an interposer wafer INT. In some embodiments, electronic integrated circuit die 300 may be picked and placed on first active surface AS1 of interposer wafer INT such that electronic integrated circuit die 300 may cover electrical bonding portion 200a of photonic integrated circuit die 200. Each electronic integrated circuit die 300 may include a second active surface AS2 and a second back surface RS2 opposite the second active surface AS2, respectively. After electronic integrated circuit die 300 is picked and placed on interposer wafer INT, second active surface AS2 of electronic integrated circuit die 300 may face interposer wafer INT and electronic integrated circuit die 300 may be bonded to interposer wafer INT through conductive bumps B1, conductive bumps B2, and solder material between conductive bumps B1 and B2. For example, a reflow process of the conductive bump B1 may be performed to facilitate bonding between the electronic integrated circuit die 300 and the interposer wafer INT. In some embodiments, the number of electronic integrated circuit dies 300 may be equal to the number of photonic integrated circuit dies 200 included in the interposer wafer INT. In some alternative embodiments, the number of electronic integrated circuit dies 300 may be greater than the number of photonic integrated circuit dies 200 included in the interposer wafer INT. The number of electronic integrated circuit dies 300 is not limiting in the present invention.

In some embodiments, the attachment of the single dummy die 100a is performed prior to the bonding of the electronic integrated circuit die 300. In some alternative embodiments, the bonding of the electronic integrated circuit die 300 is performed prior to the attachment of the single dummy die 100 a.

Referring to fig. 3D, after performing the reflow process of the conductive bumps B1 and B2 as described above, an underfill UF1 may be formed between the electronic integrated circuit die 300 and the interposer wafer INT, thereby laterally encapsulating the conductive bumps B1 and B2. The underfill UF1 not only protects the conductive bumps B1 and B2 from fatigue, but also improves the reliability of the bond between the electronic integrated circuit die 300 and the interposer wafer INT. In some embodiments, the materials of bondline G and underfill UF1 may be thermally cured polymers, and may be cured simultaneously by a thermal curing process.

In some other embodiments, the formation of underfill UF1 may be omitted.

Although the bonding and electrical connection between the electronic integrated circuit die 300 and the interposer wafer INT (as shown in fig. 3C) may be achieved by the conductive bumps B1 and B2 encapsulated by the underfill UF1, the bonding and electrical connection between the electronic integrated circuit die 300 and the interposer wafer INT is not limited by the present invention. Other suitable chip-to-wafer bonding processes (e.g., a chip-to-wafer hybrid bonding process) may also be used.

Referring to fig. 3E and 3F, an insulating encapsulant 400 is formed on the interposer wafer INT to encapsulate the individual dummy die 100a, electronic integrated circuit die 300, underfill UF1, and glue layer G. In some embodiments, the insulating sealant 400 may be formed by an overmolding process followed by a first grinding process. During the overmolding process, an insulating molding material is formed on the interposer wafer INT to encapsulate the electronic integrated circuit die 300, the underfill UF1, and the glue layer G, such that the electronic integrated circuit die 300, the underfill UF1, and the glue layer G are not exposed. Then, as shown in fig. 3F, the insulating molding material is ground or polished until the second back surface RS2 of the electronic integrated circuit die 300 and the back surface of the dummy die 100a are exposed. After performing the first grinding process, a polished insulating encapsulant 400a that laterally encapsulates the dummy die 100a and the electronic integrated circuit die 300 is formed over the interposer wafer INT. The first grinding process of the insulating molding material as described above may be a Chemical Mechanical Polishing (CMP) process, a mechanical grinding process, a combination thereof, or other suitable process.

Referring to fig. 3G, a thinning process is performed to reduce the thickness of the interposer wafer INT from the first back surface RS 1. In some embodiments, a grinding or polishing process may be performed on the first back surface RS1 of the interposer wafer INT until the electrical bonding portions 200a of the photonic integrated circuit die 200 are exposed from the first back surface RS1 of the interposer wafer INT, i.e., forming TSVs is completed. The thinning process of the interposer wafer INT as described above may be a Chemical Mechanical Polishing (CMP) process, a mechanical grinding process, a combination thereof, or other suitable process.

After performing the thinning process of the interposer wafer INT, redistribution traces RDL and conductive bumps B3 may be formed on the first back surface RS1 of the interposer wafer INT. In some embodiments, the conductive bumps B3 formed on the first back surface RS1 of the interposer wafer INT may be controlled collapse chip connection bumps (C4 bumps). For example, multiple groups of conductive bumps B3 may be formed on the first back surface RS1 of the interposer wafer INT, and each group of conductive bumps B3 may be formed on one photonic integrated circuit die 200, respectively.

After the thinning process of the interposer wafer INT is performed, the insulating molding material is further ground or polished by a second grinding process. During the second grinding process of the insulating encapsulant 400a, not only the insulating molding material is partially removed, but also portions of the electronic integrated circuit die 300 and the individual dummy die 100a are removed. After performing the second grinding process, dummy die 100b having a reduced thickness, electronic integrated circuit die 300a having a reduced thickness, and polished insulating encapsulant 400b are formed over the interposer wafer INT. As shown in fig. 3G, after the second grinding process is performed, the wall structures WS are exposed from the rear surface of the dummy die 100 b. The second grinding process of the insulating molding material as described above may be a Chemical Mechanical Polishing (CMP) process, a mechanical grinding process, a combination thereof, or other suitable process.

Referring to fig. 3H, a separation process is performed to separate the wafer-level structure shown in fig. 3G into a plurality of individual optical transceivers OTC. Portions of the insulating sealant 400b, the dummy die 100b, and the glue layer G may be removed through a separation process. As shown in fig. 3H, the alignment mark AM, portions of the wall structures WS, portions of the middle region of the dummy die 100b, and portions of the peripheral region of the dummy die 100b may be removed by a separation process. After the separation process is performed, the end of the recess 200c is exposed accessible from the sidewall of the single optical transceiver OTC.

Referring to fig. 3I, after performing the separation process, one single optical transceiver OTC is picked up and placed on the circuit substrate SUB. The conductive bump B3 of the single optical transceiver OTC is electrically connected to the wiring of the circuit substrate SUB. In some embodiments, the circuit substrate SUB is a printed circuit board that includes a plurality of conductive balls (e.g., solder balls, etc.) formed on a bottom surface. In other words, the circuit substrate SUB is a Ball Grid Array (BGA) circuit substrate.

Referring to fig. 3J, after bonding the single optical transceiver OTC with the circuit substrate SUB, an ablation process is performed to remove the wall structure WS embedded in the dummy die 100b, thereby causing the middle region CR and the protective coating PC of the dummy die 100b to be peeled off from the peripheral region D of the dummy die 100b and the photonic integrated circuit die 200. In some embodiments, the ablation process is a laser ablation process for partially or completely removing the wall structure WS. After removing the wall structure WS between the peripheral region D and the middle region CR of the dummy die 100b, the middle region of the dummy die 100b and the protective coating PC may be picked up and removed, thereby exposing the protrusions P and the recesses 200c on the photonic integrated circuit die 200. The peripheral region D may serve as a semiconductor dam (dam) (e.g., a silicon dam) for restricting the distribution of the insulating sealant 400 b. For example, the semiconductor dam D is electrically floating. After removing the middle region CR of the dummy die 100b, a chip-on-wafer-on-substrate (cogos) package with a small form factor is formed. In some embodiments, the width or length of a CoWoS package with a small form factor may range from about 1 cm to about 5 cm, while the thickness of a CoWoS package with a small form factor may range from about 1 mm to about 3 mm.

Other components and processes may also be included. For example, test structures may be included to aid in verification testing of 3D packages or 3D-IC devices. For example, the test structures may include the use of test pads, probes, and/or probe cards formed in a redistribution layer or on a substrate that allows for testing of 3D packages or 3D-ICs, and the like. The verification test may be performed on the intermediate structure as well as on the final structure. Further, the structures and methods disclosed herein may be used in conjunction with testing methodologies that incorporate intermediate verification of known good dies to increase yield and reduce cost.

In some embodiments, underfill UF2 may be formed between the single optical transceiver OTC and the circuit substrate SUB to laterally encapsulate photonic integrated circuit die 200 and conductive bumps B3. In some alternative embodiments, the formation of underfill UF2 may be omitted.

Referring to fig. 3K, after removing the middle region CR of the dummy die 100b, an optical fiber FB is provided and assembled into the recess 200 c. In some embodiments, an optical fiber FB is provided and inserted laterally into the recess. The optical fiber FB extends laterally along the recess 200c and is optically coupled to the optical input/output portion 200b of the photonic integrated circuit die 200. Since the optical fiber FB assembled to the recess 200c extends laterally, the assembly including the optical transceiver OTC and the optical fiber FB is compact.

As shown in fig. 3K, peripheral region D (e.g., semiconductor dam) is spaced a distance D1 from electronic integrated circuit die 300 a. In other words, distance D1 represents the width of the portion of insulating encapsulant 400b between electronic integrated circuit die 300a and peripheral region D (e.g., semiconductor dam). For example, distance D1 ranges from between about 30 microns to about 200 microns.

Fig. 4 schematically illustrates a perspective view of the interposer shown in fig. 3A and a single dummy die shown in fig. 2. In an embodiment, a single dummy die 100a is picked and placed on the first active surface AS1 of the interposer wafer INT. A single dummy die 100a is attached on the first active surface AS1 of the interposer wafer INT by a glue layer G. Figure 5 schematically illustrates a top view of a CoWoS package according to some embodiments of the invention. Fig. 3K schematically illustrates a cross-sectional view along the line I-I' shown in fig. 5, according to some embodiments of the invention. Fig. 6 schematically illustrates a cross-sectional view along line II-II' shown in fig. 5, according to some embodiments of the invention.

As shown in fig. 3K, 5 and 6, after removing the middle region CR (shown in fig. 3J) of the dummy die 100b, a notch N is formed over the photonic integrated circuit die 200 to expose the recess 200c, thereby enabling easier assembly of the optical fiber FB into the recess 200 c. Therefore, the yield of the optical fiber FB assembly can be improved.

Figures 7 and 8 schematically illustrate cross-sectional views of a CoWoS package according to various embodiments of the present invention.

Referring to fig. 3K and 7, the CoWoS package shown in fig. 3K and 7 is similar, but the insulating sealant 400b shown in fig. 7 is not filled between the electronic integrated circuit die 300a and the peripheral region D (e.g., the semiconductor dam). Underfill UF1 is dispensed to entirely fill the space between electronic integrated circuit die 300a and peripheral region D, such as by dispensing underfill UF1 between peripheral region D and electronic integrated circuit die 300 a. As shown in fig. 7, peripheral region D (e.g., semiconductor dam) is spaced a distance D2 from electronic integrated circuit die 300 a. In other words, distance D2 represents the width of the portion of underfill UF1 between electronic integrated circuit die 300a and peripheral region D (e.g., semiconductor dam). For example, distance D2 ranges from between about 30 microns to about 200 microns.

Referring to fig. 7 and 8, the CoWoS package shown in fig. 7 and 8 is similar, but the perimeter region D (e.g., semiconductor dam) shown in fig. 8 is separated from the electronic integrated circuit die 300a by portions of underfill UF1 and portions of insulating encapsulant 400 b. For example, underfill UF1 is dispensed to fill the portion of the space between electronic integrated circuit die 300a and peripheral region D, allowing insulating encapsulant 400b to fill the remainder of the space between electronic integrated circuit die 300a and peripheral region D. For example, distance D2 ranges from between about 30 microns to about 200 microns.

Fig. 9-11 schematically illustrate top views of a CoWoS package according to various embodiments of the present invention.

Referring to fig. 5 and 9, the top views of the CoWoS package shown in fig. 5 and 9 are similar, but the CoWoS package shown in fig. 9 does not include the protrusion P.

Referring to fig. 9 and 10, the top views of the CoWoS package shown in fig. 9 and 10 are similar, but the dam D of the CoWoS package shown in fig. 10 is a comb-shaped dam. As shown in fig. 10, the comb-shaped semiconductor dam D includes a plurality of parallel notches N. In some embodiments, the notches N expose the recess 200c, and the parallel notches N may extend substantially parallel to the recess 200 c.

Referring to fig. 10 and 11, the top views of the CoWoS package shown in fig. 10 and 11 are similar, but the CoWoS package shown in fig. 11 further includes a plurality of protrusions P, wherein each protrusion P is respectively distributed to correspond to one recess N of the semiconductor dam D.

By employing the embodiments described herein, photonic fibers may be incorporated in an interposer, such as a silicon interposer. Furthermore, by implementing the embodiments in a System On Integrated Chip (SOIC), electrical losses can be minimized, resulting in a more efficient final device.

According to some embodiments of the present invention, a photonic integrated circuit die, an electronic integrated circuit die, a semiconductor dam, and an insulating encapsulant are provided. The photonic integrated circuit die includes an optical input/output portion and a recess located proximate the optical input/output portion, wherein the recess is adapted for lateral insertion of at least one optical fiber. An electronic integrated circuit die is disposed over and electrically connected to the photonic integrated circuit die. A semiconductor dam is disposed over the photonic integrated circuit die. An insulating encapsulant is disposed over the photonic integrated circuit die and laterally encapsulates the electronic integrated circuit die and the semiconductor dam.

According to some other embodiments of the present invention, a structure is provided that includes a photonic integrated circuit die, an electronic integrated circuit die, a semiconductor dam, and an insulating encapsulant. The photonic integrated circuit die includes an optical input/output portion and a fiber insertion recess located near the optical input/output portion. An electronic integrated circuit die and a semiconductor dam are disposed in a side-by-side manner over the photonic integrated circuit die, wherein the electronic integrated circuit die is electrically connected to the photonic integrated circuit die. An insulating encapsulant is disposed over the photonic integrated circuit die and laterally encapsulates the electronic integrated circuit die and the semiconductor dam, wherein a side surface of the semiconductor dam is accessibly exposed by the insulating encapsulant, and the semiconductor dam separates the optical fiber insertion recess from the insulating encapsulant.

According to some alternative embodiments of the present invention, a method is provided that includes the following steps. A photonic integrated circuit die is provided that includes at least one optical input/output portion and at least one recess located proximate to the optical input/output portion. The electronic integrated circuit die and the dummy die are bonded on the photonic integrated circuit die. A portion of the dummy die is removed to form a semiconductor dam having a recess such that at least one recess is exposed by the recess of the semiconductor dam.

According to an embodiment of the present invention, there is provided a semiconductor structure including: a photonic integrated circuit die comprising an optical input/output portion and a recess located proximate to the optical input/output portion; an electronic integrated circuit die disposed over and electrically connected to the photonic integrated circuit die; a semiconductor dam disposed over the photonic integrated circuit die; and an insulating encapsulant disposed over the photonic integrated circuit die, laterally encapsulating the electronic integrated circuit die, and in physical contact with the semiconductor dam.

According to an embodiment of the present invention, the electronic integrated circuit die is electrically connected to the photonic integrated circuit die by a plurality of micro-bumps.

According to an embodiment of the present invention, the semiconductor dam includes a recess, and the recess is accessibly exposed by the recess of the semiconductor dam.

According to an embodiment of the present invention, further comprising: a protrusion disposed over the photonic integrated circuit die, wherein the protrusion is accessibly exposed by the recess of the semiconductor dam.

According to an embodiment of the present invention, further comprising: a glue layer located between the semiconductor dam and the photonic integrated circuit die.

According to an embodiment of the invention, further comprising at least one optical fiber located in the recess.

According to an embodiment of the present invention, further comprising: a circuit substrate, wherein the photonic integrated circuit die is disposed over and electrically connected to the circuit substrate.

According to an embodiment of the present invention, further comprising: a plurality of conductive bumps; and an underfill disposed between the circuit substrate and the photonic integrated circuit die, wherein the photonic integrated circuit die is electrically connected to the circuit substrate through the conductive bumps, and the conductive bumps are encapsulated by the underfill.

According to an embodiment of the present invention, there is provided a semiconductor structure including: a photonic integrated circuit die comprising an optical input/output portion and a fiber recess located proximate to the optical input/output portion; an electronic integrated circuit die and a semiconductor dam disposed in a side-by-side manner over the photonic integrated circuit die, the electronic integrated circuit die being electrically connected to the photonic integrated circuit die; an insulating encapsulant disposed over the photonic integrated circuit die, laterally encapsulating the electronic integrated circuit die, and in physical contact with multiple sides of the semiconductor dam, wherein side surfaces of the semiconductor dam are exposed accessible by the insulating encapsulant, and the semiconductor dam separates the fiber recess from the insulating encapsulant; and at least one optical fiber in the optical fiber recess.

According to an embodiment of the present invention, the semiconductor dam includes a notch, the optical fiber recess is accessibly exposed by the notch of the semiconductor dam, and the insulating sealant is not located in the notch of the semiconductor dam.

According to an embodiment of the present invention, further comprising: a protrusion disposed over the photonic integrated circuit die, wherein the protrusion is accessibly exposed by the recess of the semiconductor dam.

According to an embodiment of the present invention, a top surface of the electronic integrated circuit die is flush with a top surface of the semiconductor dam.

According to an embodiment of the present invention, further comprising: a circuit substrate, wherein the photonic integrated circuit die is disposed over and electrically connected to the circuit substrate.

According to an embodiment of the present invention, further comprising: a plurality of conductive bumps; and an underfill disposed between the circuit substrate and the photonic integrated circuit die, wherein the photonic integrated circuit die is electrically connected to the circuit substrate through the conductive bumps, the conductive bumps are encapsulated by the underfill, and at least a portion of the underfill is covered by the insulating encapsulant.

According to an embodiment of the present invention, the underfill completely fills the space between the electronic integrated circuit die and the semiconductor dam.

According to an embodiment of the present invention, the underfill and the insulating sealant completely fill a space between the electronic integrated circuit die and the semiconductor dam.

According to an embodiment of the present invention, there is provided a method of forming a semiconductor structure, including: providing a photonic integrated circuit die comprising at least one optical input/output portion and at least one recess; bonding an electronic integrated circuit die and a dummy die on the photonic integrated circuit die; and removing a portion of the dummy die to form a semiconductor dam having a recess such that the at least one recess is exposed by the recess of the semiconductor dam.

According to an embodiment of the present invention, further comprising: assembling at least one optical fiber into the at least one recess.

According to an embodiment of the present invention, further comprising: mounting the photonic integrated circuit die with the electronic integrated circuit die and the dummy die bonded thereto over a circuit substrate prior to removing a portion of the dummy die.

According to an embodiment of the present invention, further comprising: laterally packaging the electronic integrated circuit die and the dummy die bonded on the photonic integrated circuit die prior to removing a portion of the dummy die.

The components of the various embodiments are discussed above so that those of ordinary skill in the art may better understand the various aspects of the present invention. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure.