阅读说明：本技术 半导体元件及其制备方法 (Semiconductor element and method for manufacturing the same ) 是由 施江林 吴珮甄 张庆弘 丘世仰 于 2019-10-11 设计创作，主要内容包括：本公开提供一种半导体元件及其制备方法。该半导体元件具有一第一晶粒、一第二晶粒、一第一重新分布层、一第二重新分布层、一第一互连结构以及一第二互连结构。该第二晶粒叠置在该第一晶粒上,该第一重新分布层配置在该第一晶粒的一第一基底与该第二晶粒的一第二层间介电层之间,且该第二重新分布层配置在该第二晶粒的一第二基底上。该第一互连结构将该第一重新分布层连接到该第一晶粒的多个第一金属线的其中一个,且该第二互连结构将该第二重新分布层连接到在该第二层间介电层中的多个第二金属线的其中一个。(The present disclosure provides a semiconductor device and a method of manufacturing the same. The semiconductor device has a first die, a second die, a first redistribution layer, a second redistribution layer, a first interconnect structure, and a second interconnect structure. The second die is stacked on the first die, the first redistribution layer is disposed between a first substrate of the first die and a second interlayer dielectric layer of the second die, and the second redistribution layer is disposed on a second substrate of the second die. The first interconnect structure connects the first redistribution layer to one of the first plurality of metal lines of the first die, and the second interconnect structure connects the second redistribution layer to one of the second plurality of metal lines in the second interlevel dielectric layer.)

1. A semiconductor component, comprising:

a first die including a first substrate, a first interlayer dielectric layer disposed on a front surface of the first substrate, and a plurality of first metal lines disposed in the first interlayer dielectric layer;

a second die overlying the first die and including a second substrate, a second interlayer dielectric layer disposed on a second front surface of the second substrate, and a plurality of second metal lines disposed in the second interlayer dielectric layer;

a first redistribution layer between the first substrate and the second interlayer dielectric layer;

a second redistribution layer disposed on the second substrate;

a first interconnect structure extending through the first substrate and through the first interlevel dielectric layer to connect the first redistribution layer to one of the first metal lines; and

a second interconnect structure extending through the second substrate and into the second interlevel dielectric layer to connect the second redistribution layer to one of the second metal lines.

2. The semiconductor device of claim 1, wherein the first redistribution layer is aligned with the first interconnect structure and offset from the second metal line when viewed in cross-section.

3. The semiconductor device of claim 1, wherein the second metal line fully connected to the first redistribution layer exposes the second interlayer dielectric layer.

4. The semiconductor device of claim 1, further comprising at least one solder bump electrically connected to the second redistribution layer.

5. The semiconductor device of claim 4, further comprising at least one under bump metallization layer interposed between the solder bumps and the second redistribution layer.

6. The semiconductor device of claim 1, further comprising a carrier bonded to the first die by a bonding layer.

7. The semiconductor device of claim 6, wherein the bonding layer comprises a native dielectric film grown on the carrier and a deposited dielectric layer on the first interlayer dielectric layer.

8. The semiconductor device of claim 6, wherein the first redistribution layer has a first thickness and the second redistribution layer has a second thickness, the second thickness being less than the first thickness.

9. A method for fabricating a semiconductor device comprises

Providing a first die comprising a first substrate, a first interlayer dielectric layer disposed on a first front surface of the first substrate, and a plurality of first metal lines disposed in the interlayer dielectric layer;

forming a first interconnect structure through the first substrate, through the first interlayer dielectric layer, and contacting one of the first metal lines;

forming a first redistribution layer completely connecting the first interconnect structure;

providing a second die comprising a second substrate, a second interlayer dielectric layer disposed on a second front surface of the second substrate, and a plurality of second metal lines in the second interlayer dielectric layer;

forming a second redistribution layer to completely connect one of the second metal lines;

stacking the second die on the first die and completely connecting the first redistribution layer to the second redistribution layer;

forming a second interconnect structure through the second substrate, through the second interlayer dielectric layer, and contacting one of the second conductive lines; and

a second redistribution layer is formed on the second substrate and completely connects the second interconnect structure.

10. The method of claim 9, wherein the first redistribution layer and the second redistribution layer have an identical pattern.

11. The method of claim 9, further comprising:

a dielectric layer is formed surrounding the first redistribution layer and the second redistribution layer.

12. The method of claim 9, further comprising:

providing a carrier;

forming a dielectric film on the first interlayer dielectric layer; and

bonding the first crystal grain and the carrier through the dielectric film.

13. The method of claim 12, further comprising performing a grinding process to thin the carrier after the second redistribution layer is formed.

14. The method of claim 9, wherein the forming of the first interconnect structure comprises:

forming at least one first opening to expose the first metal line; and

depositing a first conductive material in the first opening;

wherein the forming of the second interconnect structure comprises:

forming at least one second opening to expose the second metal line; and

depositing a second conductive material in the second opening.

15. The method of claim 14, further comprising:

depositing a first barrier layer on the first substrate and in the first opening prior to depositing the first conductive material;

performing a first planarization process after the first conductive material is deposited to remove portions of the first barrier layer and the first conductive material, thereby exposing the first substrate;

depositing a second barrier layer on the second substrate and in the second opening prior to depositing the second conductive material; and

after the second conductive material is deposited, a second planarization process is performed to remove portions of the second barrier layer and the second conductive material, thereby exposing the second substrate.

16. The method of claim 9, further comprising:

performing a first thinning process to thin the first substrate before the first interconnect structure is formed; and

a second thinning process is performed to thin the second substrate before the second interconnect structure is formed.

Technical Field

The present application claims priority and benefits of U.S. official application No. 16/401,587 of the 2019/05/02 application, the contents of which are incorporated herein by reference in their entirety.

The present disclosure relates to a semiconductor device and a method for manufacturing the same. In particular to a stacked die device and a method of making the same.

Background

As integrated circuit technology continues to advance, there is a continuing effort to improve performance and density, improve form factor (form factor), and reduce cost. One approach to achieving such advantages, which has been explored by many designers, is implemented by stacked three-dimensional (3D) integrated circuits. It is desirable to consider regions of a three-dimensional integrated circuit that have a stack of two or more wafers that are fabricated using different fabrication processes (fabrication processes) or that are electrically stacked using the same fabrication process to reduce the footprint of the integrated circuit device (footprint).

The above description of "prior art" is merely provided as background, and is not an admission that the above description of "prior art" discloses the subject matter of the present disclosure, does not constitute prior art to the present disclosure, and that any description of "prior art" above should not be taken as an admission that it is prior art to the present disclosure.

Disclosure of Invention

An embodiment of the present disclosure provides a semiconductor device. The semiconductor device includes a first die (first die), a second die, a first redistribution layer (first redistribution layer), a second redistribution layer, a first interconnect structure (first interconnect structure), and a second interconnect structure. The first die includes a first substrate, a first interlayer dielectric (ILD) layer disposed on a front surface of the first substrate, and a plurality of first metal lines disposed in the first ILD layer. The second die is stacked on the first die and includes a second substrate, a second interlayer dielectric layer disposed on a second front surface of the second substrate, and a plurality of second metal lines disposed in the second interlayer dielectric layer. The first redistribution layer is between the first substrate and the second interlayer dielectric layer. The second redistribution layer is disposed on the second substrate. The first interconnect structure penetrates through the first substrate and penetrates through the first interlayer dielectric layer to connect the first redistribution layer to one of the first metal lines. The second interconnect structure penetrates through the second substrate and into the second interlayer dielectric layer to connect the second redistribution layer to one of the second metal lines.

According to some embodiments of the present disclosure, the first redistribution layer is aligned with the first interconnect structure and offset from the second metal line when viewed in a cross-sectional view.

According to some embodiments of the present disclosure, the second metal line completely connected to the first redistribution layer exposes the second interlayer dielectric layer.

According to some embodiments of the present disclosure, the semiconductor device further includes at least one solder bump (solder bump) electrically connected to the second redistribution layer.

According to some embodiments of the present disclosure, the semiconductor device further includes at least one Under Bump Metallization (UBM) interposed between the solder bumps and the second redistribution layer.

According to some embodiments of the present disclosure, the semiconductor device further includes a carrier (carrier) bonded to the first die by a bonding layer.

According to some embodiments of the present disclosure, the bonding layer includes a native dielectric film (native dielectric film) grown on the support and a deposited dielectric layer (deposited dielectric layer) on the first interlayer dielectric layer.

According to some embodiments of the disclosure, the first redistribution layer has a first thickness and the second redistribution layer has a second thickness, the second thickness being less than the first thickness.

Another embodiment of the present disclosure provides a method for manufacturing a semiconductor device. The preparation method comprises the following steps: providing a first die comprising a first substrate, a first interlayer dielectric layer disposed on a first front surface of the first substrate, and a plurality of first metal lines disposed in the interlayer dielectric layer; forming a first interconnect structure through the first substrate, through the first interlayer dielectric layer, and contacting one of the first metal lines; forming a first re-routing layer (re-routing layer) completely connecting the first interconnect structure; providing a second die comprising a second substrate, a second interlayer dielectric layer disposed on a second front surface of the second substrate, and a plurality of second metal lines in the second interlayer dielectric layer; forming a second redistribution layer to completely connect one of the second metal lines; stacking the second die on the first die and completely connecting the first redistribution layer to the second redistribution layer; forming a second interconnect structure through the second substrate, through the second interlayer dielectric layer, and contacting one of the second conductive lines; and forming a second redistribution layer on the second substrate and fully connecting the second interconnect structure.

According to some embodiments of the present disclosure, the first redistribution layer. The second redistribution layer has a pattern identical to that of the first redistribution layer.

According to some embodiments of the present disclosure, the method further includes forming a dielectric layer surrounding the first redistribution layer and the second redistribution layer.

According to some embodiments of the disclosure, the method of preparing further comprises: providing a carrier; forming a dielectric film (dielectric film) on the first interlayer dielectric layer; and bonding the first crystal grain and the carrier through the dielectric film.

According to some embodiments of the present disclosure, the manufacturing method further includes performing a grinding process after the second redistribution layer is formed to thin the carrier.

According to some embodiments of the present disclosure, the forming of the first interconnect structure includes: forming at least one first opening to expose the first metal line; and depositing a first conductive material in the first opening; wherein the forming of the second interconnect structure comprises: forming at least one second opening to expose the second metal line; and depositing a second conductive material in the second opening.

According to some embodiments of the disclosure, the method of preparing further comprises: depositing a first barrier layer (first barrier layer) on the first substrate and in the first opening prior to depositing the first conductive material; performing a first planarization process after the first conductive material is deposited to remove portions of the first barrier layer and the first conductive material, thereby exposing the first substrate; depositing a second barrier layer on the second substrate and in the second opening prior to depositing the second conductive material; and performing a second planarization process after the second conductive material is deposited to remove portions of the second barrier layer and the second conductive material, thereby exposing the second substrate.

According to some embodiments of the disclosure, the method of preparing further comprises: performing a first thinning process (first thinning process) to thin the first substrate before the first interconnect structure is formed; and performing a second thinning process to thin the second substrate before the second interconnect structure is formed.

The foregoing has outlined rather broadly the features and advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages will be described hereinafter which form the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures or processes for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the disclosure as set forth in the appended claims.

Drawings

The disclosure may be more completely understood in consideration of the following detailed description and the appended claims, in connection with the accompanying drawings, in which like reference numerals refer to like elements.

Fig. 1 is a schematic cross-sectional view of a semiconductor system according to some embodiments of the present disclosure.

Fig. 2 is a schematic cross-sectional view of a semiconductor system according to some embodiments of the present disclosure.

Fig. 3 is a flow chart illustrating a method of fabricating a semiconductor device according to some embodiments of the present disclosure.

Fig. 4-25 are schematic cross-sectional views of intermediate stages of a method of fabricating a semiconductor device according to some embodiments of the present disclosure.

Wherein the reference numerals are as follows:

10 semiconductor system

10A semiconductor system

12 mainboard

14 semiconductor element

14A semiconductor element

20a first die

20b second die

20c third grain

20d fourth crystal grain

30 vector

32 bonding layer

34 first redistribution layer

36 second redistribution layer

38 dielectric material

40 solder bump

42 underbump metallization layer

50 preparation method

122 support assembly

124 wiring pad

142 depositing a dielectric film

210a first substrate

210b second substrate

210c third substrate

210d fourth substrate

212a front surface

212b second front surface

214a first rear surface

214b second rear surface

220a first interlayer dielectric layer

220b second interlayer dielectric layer

220c third interlayer dielectric layer

220d fourth interlayer dielectric layer

222b top surface

230a first metal line

230b second metal line

230c third metal line

230d fourth Metal line

232b top surface

240a first interconnect structure

240b second interconnect structure

240c third interconnect Structure

250a first barrier layer

250b second barrier layer

260a first opening

270a first conductive material

270b second conductive material

280a first precursor layer

280b second precursor layer

282a first rewiring layer

282b second rewiring layer

284a first dielectric layer

284b second dielectric layer

290b second opening

300 third precursor layer

301 surface

302 native dielectric film

362 Top surface

382 top surface

502 step

504 step

Step 506

508 step

Step 510

512 step

514 step

516 step

518 step

520 step

522 step

Step 524

526 step

528 step

530 step

532 step

534 step

536 step

538 step

540 step

542 step

544 step

546 step

548 step

610 first photoresist pattern

620 first mask

630 second photoresist pattern

640 second mask

1222 surface of

2822a top surface

2822b Top surface

2842a top surface

2842b Top surface

C center shaft

T1 first thickness

T2 second thickness

T3 thickness

T4 thickness

T5 thickness

T6 thickness

T7 thickness

T8 thickness

Detailed Description

The following description of the present disclosure, which is accompanied by the accompanying drawings incorporated in and forming a part of the specification, illustrates embodiments of the present disclosure, however, the present disclosure is not limited to the embodiments. In addition, the following embodiments may be appropriately integrated to complete another embodiment.

References to "one embodiment," "an example embodiment," "other embodiments," "another embodiment," etc., indicate that the embodiment described in this disclosure may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, repeated usage of the phrase "in an embodiment" does not necessarily refer to the same embodiment, but may.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The present disclosure is directed to a semiconductor device and a method of fabricating the same. The following description is provided to provide detailed steps and structures for a thorough understanding of the present disclosure. It is apparent that the implementation of the disclosure does not limit the specific details known to a person with ordinary skill in the art. In addition, well-known structures and steps are not shown in detail to avoid unnecessarily limiting the disclosure. Preferred embodiments of the present disclosure are described in detail below. However, the present disclosure may be practiced in other embodiments, which depart from the specific details. The scope of the present disclosure is not limited by the detailed description but is defined by the claims.

Fig. 1 is a schematic cross-sectional view of a semiconductor system 10 in accordance with some embodiments of the present disclosure. Referring to fig. 1, a semiconductor system 10 includes a main board (main board)12 and a semiconductor device 14, the semiconductor device 14 is mounted on and electrically connected to the main board 12, wherein the semiconductor device 14 includes a first die 20a and a second die 20b, and the first die 20a and the second die 20b are vertically stacked to form a front-to-back configuration.

In some embodiments, the motherboard 12 may be a circuit board (circuit board) or a motherboard (thermal board) of an electronic system (electronic system), such as a computer system (computer). In some embodiments, the motherboard 12 has a support member (support member)122 and a plurality of wiring pads (wiring pads)124, the wiring pads 124 being disposed on a surface 1222 of the support member 122. In some embodiments, the support member 122 may be made of a dielectric material, such as bismaleimide-triazine (BT) resin or FR4 (composed of woven fiberglass cloth and fire-retardant epoxy resin adhesive)/glass; the wiring pads 123 may be gold-plated conductors, copper-plated conductors, or aluminum-plated conductors.

In some embodiments, the semiconductor device 14 further includes a carrier 30, wherein the first die 20a is stacked and bonded to the carrier 30 in a dielectric-to-dielectric bonding (di-electric bonding) process, wherein a bonding layer 32 may be interposed between the first die 20a and the carrier 30. In some embodiments, the carrier 30 may be a bare silicon wafer (bare silicon wafer) without any electrical circuitry (electrical circuitry) disposed thereon. In some embodiments, the bonding layer 32 has a deposited dielectric film (deposited dielectric film)142 and a native dielectric film (native dielectric film)302, the deposited dielectric film 142 being, for example, silicon dioxide (SiO)₂) And is located on the first crystal grain 20a, and when the carrier 30 is exposed to oxygen and water in the air, a native dielectric film 302 is formed. In some embodiments, the deposited dielectric film 142 provides a high quality bonding interface to facilitate bonding with the carrier 30.

In some embodiments, the first die 20a and the second die 20b may be fabricated using the same fabrication process. For example, the first die 20a and the second die 20b may form a memory stack (memory stack). However, in some embodiments, the first die 20a and the second die 20b may be fabricated using different fabrication flows. For example, one of the first die 20a and the second die 20b may be a memory device (memory device), and the other of the first die 20a and the second die 20b may be a processor (processor), an image sensor (image sensor), or an Application Specific Integrated Circuit (ASIC) device.

The first die 20a has a first substrate 210a and a first interlayer dielectric (ILD) layer 220a, the first ILD 220a is disposed on a front surface 212a of the first substrate 210 a. In some embodiments, the first substrate 210a may also include a number of different layers, which are not separately drawn and which combine to form different microelectronic elements (microelectronics), which may include transistors, resistors, diodes, capacitors, inductors, fuses, or other suitable elements, or combinations thereof. The different layers may include dielectric layers (dielectric layers), gate layers (gate layers), interfacial layers (interfacial layers), diffusion/barrier layers (diffusion/barrier layers), conductive layers (conductive layers), other suitable layers, or combinations thereof. The different layers of the first substrate 210a may also include different doped regions (doped regions), isolation features (isolation features), other features, or combinations thereof. Furthermore, such microelectronic devices may be interconnected to form a portion of the first substrate 210, such as a logic device, a memory device, a radio frequency (rf) device, an input/output (i/o) device, a system-on-chip (system-on-chip) device, other suitable type of device, or a combination thereof.

In some embodiments, a first interlayer dielectric layer 220a covers the microelectronic elements, the doped regions, and the isolation features. In some embodiments, the deposited dielectric film 142 is deposited on the first interlayer dielectric layer 220 a. In some embodiments, the first interlayer dielectric layer 220a is a dielectric (dielectric) and may comprise an oxide (oxide), a nitride (nitride), or an oxynitride (oxynitride).

In some embodiments, the first die 20a further includes a plurality of first metal lines (230 a), the first metal lines 230a being disposed in the first interlayer dielectric layer 220 a. In some embodiments, the first metal line 230a may be electrically connected to the microelectronic element and may include aluminum, copper, tungsten, titanium, or the like.

In some embodiments, the semiconductor device 14 further includes at least one first interconnection structure (first interconnection structure)240a, and the first interconnection structure 240a completely connects at least one of the first metal lines 230 a. In some embodiments, the first interconnect structure 240a penetrates through the first substrate 210a and penetrates the first interlayer dielectric layer 220a, and contacts the first metal line 230a closest to the first substrate 210 a. In some embodiments, the first interconnect structure 240a may include aluminum, copper, tungsten, cobalt (Co), polysilicon (polysilicon), or other suitable conductive material.

In some embodiments, the semiconductor device 14 may further include a first barrier layer 250a, the first barrier layer 250a being interposed between the first substrate 210a and the first interconnect structure 240a, between the first interlayer dielectric layer 220a and the first interconnect structure 240a, and between the first metal line 230a and the first interconnect structure 240 a. In some embodiments, the first barrier layer 250a functions as a glue layer. In some embodiments, refractory metals (refractory metals), refractory metal nitrides (refractory metal nitrides), and combinations thereof are typically used in first barrier layer 250 a. In some embodiments, the first barrier layer 250a may comprise titanium, titanium nitride (TiN), tantalum (Ta), tantalum nitride (TaN), titanium silicon nitride (TiSiN), tantalum silicon nitride (TaSiN), or the like. In some embodiments, a seed layer (not shown) may be interposed between the first interconnect structure 240a and the first barrier layer 250a to facilitate formation of the first interconnect structure 240 a.

The second die 20b has a second substrate 210b, a second interlayer dielectric layer 220b and a plurality of second metal lines 230b, the second interlayer dielectric layer 220b is disposed on a second front surface 212b of the second substrate 210b, and the second metal lines 230b are disposed in the second interlayer dielectric layer 220 b. In some embodiments, the second substrate 210b may also include a number of different layers that are not separately drawn and which combine to form different microelectronic elements, doped regions, and isolation features covered by the second interlayer dielectric layer 220 b. In some embodiments, some of the second metal lines 230b are exposed through the second interlayer dielectric layer 220b to provide a landing area (landing area) of a first redistribution layer (first redistribution layer)34, which will be described in detail later.

In some embodiments, the semiconductor component 14 further includes at least one second interconnect structure 240b, the second interconnect structure 240b extending from a second back surface 214b to one of the second metal lines 230b, the second back surface 214b being disposed opposite the second front surface 212 b. In some embodiments, the semiconductor device 14 may further include a second barrier layer 250b, wherein the second barrier layer 250b is disposed around the second interconnect structure 240b and is interposed between the second interconnect structure 240b and the corresponding second metal line 230 b.

A first redistribution layer 34 between the first die 20a and the second die 20b connects the first interconnect structure 240a to the second metal line 230 b. In other words, first interconnect structure 240a connects first metal line 230a to first redistribution layer 34. In some embodiments, from the cross-sectional view, the first redistribution layer 34 is aligned with the first interconnect structure 240a and offset from the corresponding second metal line 230 b. In some embodiments, the first redistribution layer 34 may include aluminum, tungsten, titanium, gold, platinum (Pt), or a combination thereof.

In some embodiments, the semiconductor element 14 may further include a second redistribution layer 36, the second redistribution layer 36 being connected to the second interconnect structure 240 b. In other words, the second interconnect structure 240b connects the second metal line 230b to the second redistribution layer 36. In some embodiments, the first redistribution layer 34 has a first thickness T1, and the second redistribution layer 36 has a second thickness T2, the second thickness T2 being less than the first thickness T1.

In some embodiments, the semiconductor device 14 may further include a dielectric material 38, and the dielectric material 38 is disposed around the first redistribution layer 34 and the second redistribution layer 36. Dielectric material 38 may increase the mechanical strength (mechanical strength) of the connection (attachment) between first die 20a and second die 20b and reduce corrosion (corrosion) of first redistribution layer 34 and second redistribution layer 26. In some embodiments, the dielectric material 38 may comprise an oxide, such as silicon dioxide.

The semiconductor device 14 may further include at least one solder bump (solder bump)40, wherein the solder bump 40 is electrically connected to the second redistribution layer 36. In some embodiments, the solder bumps 40 fully connected to the wiring pads 124 are used as input/output (I/O) connections to electrically connect the semiconductor device 14 to the motherboard 12. In some embodiments, the solder bump 40 is located at a position corresponding to the wire pad 124 so as to be completely and electrically connected. In some embodiments, the semiconductor device 14 may further include at least one Under Bump Metallization (UBM)42, the UBM 42 being interposed between the second redistribution layer 36 and the solder bumps 40. In some embodiments, the underbump metallization layer 42 comprises aluminum.

Fig. 2 is a schematic cross-sectional view of a semiconductor system 10A in accordance with some embodiments of the present disclosure. Referring to fig. 2, a semiconductor system 10A has a motherboard 12 and a semiconductor device 14A, the semiconductor device 14A is mounted on the motherboard 12 and has first to fourth dies 20A-20 d vertically stacked in a front-to-back configuration. Specifically, the third die 20c is stacked on the fourth die 20d, the second die 20b is stacked on the third die 20c, and the first die 20a is stacked on the second die 20 b. In some embodiments, the first die 20a is bonded to a carrier 30 by a bonding layer 32, wherein the bonding layer 32 is disposed on a first interlayer dielectric layer 220a of the first die 20a to provide a high quality bonding interface. In some embodiments, the bonding layer 32 contacts some of the first metal lines 230a exposed through the first interlayer dielectric layer 220 a.

In some embodiments, the semiconductor device 14A further includes a plurality of first redistribution layers 34, and the first redistribution layers 34 are disposed between two adjacent wafers 20a and 20b, 20b and 20c, and 20c and 20 d. In particular, one of the first redistribution layers 34, e.g., between the first die 20a and the second die 20b, connects at least one of the second metal lines 230b of the second die 20b to at least one first interconnect structure 240 a; another first redistribution layer 34, for example located between the second die 20b and the third die 20c, connects at least one of said third metal lines 230c of the third die 20c to at least one second interconnect structure; and yet another first redistribution layer 34, e.g., located between third die 20c and fourth die 20d, connects at least one of the fourth metal lines 230d of fourth die 20d to at least one third interconnect structure 240 c.

In some embodiments, the semiconductor device 14A further includes a second redistribution layer 36, the second redistribution layer 36 completely connecting the at least one fourth metal line 230d of the fourth die 240d to the one or more Under Bump Metallization (UBM) 42. In some embodiments, the semiconductor device 14A further includes one or more solder bumps 40, the solder bumps 40 being disposed on an Under Bump Metallization (UBM)42 connected to the second redistribution layer 36. In some embodiments, a dielectric material 38 is applied between a first substrate 210a of the first die 20a and a second interlayer dielectric 220b of the second die 20b, between a second substrate 210b of the second die 20b and a third interlayer dielectric 220c of the third die 20c, and between a third substrate 210c of the third die 20c and a fourth interlayer dielectric 220d of the fourth die 20 d; and dielectric material 38 surrounds first redistribution layer 34. In some embodiments, the dielectric material 38 is also coated on a fourth substrate 210d of the fourth die 20d and surrounds the second redistribution layer 36.

Fig. 3 is a flow chart illustrating a method of fabricating a semiconductor device 14 according to some embodiments of the present disclosure. Fig. 4-25 are schematic cross-sectional views of intermediate stages of a method 50 of fabricating a semiconductor device 14 according to some embodiments of the present disclosure. The stages shown in fig. 4-25 are also drawn schematically in the flow chart of fig. 3. In the following discussion, the stages of fabrication illustrated in fig. 4-25 are discussed with reference to the process steps illustrated in fig. 3.

Referring to fig. 4, a first die 20a and a carrier 30 are provided according to a step 502 in fig. 3. In some embodiments, the first die 20a has a first substrate 210a, a first interlayer dielectric layer 220a and a plurality of first metal lines 230a, the first interlayer dielectric layer 220a is disposed on a front surface 212a of the first substrate 210a, and the first metal lines 230a are disposed in the first interlayer dielectric layer 220 a. In fig. 4, the first die 20a is disposed upside down such that the first interlayer dielectric layer 220a faces the carrier 30. The first substrate 210a may be a doped bulk silicon (doped bulk silicon), an undoped bulk silicon (undoped bulk silicon), or an active layer of a semiconductor-on-insulator (SOI), and may have a number of different layers, which are not separately drawn and which combine to form different microelectronic elements, doped regions, and isolation features. In some embodiments, the first substrate 210a has an initial thickness T3, which may be 775 μm, for example.

In some embodiments, a dielectric film 142 containing oxide is deposited on the first interlayer dielectric layer 220a using a vapor deposition process. In some embodiments, a native dielectric film 302 is grown on a surface 301 of the carrier 30. In some embodiments, the carrier 30 has a thickness T4, for example, greater than 750 μm, such as 775 μm.

Referring to fig. 5, in some embodiments, first die 20a is bonded to carrier 30 in accordance with a step 504 of fig. 3. In some embodiments, first die 20a is bonded to carrier 30 with a dielectric-to-dielectric bonding process, such as an oxide fusion bonding (oxide bonding) process.

Referring to fig. 6, in some embodiments, a first thinning process is performed to thin the first substrate 210a according to a step 506 in fig. 3. In some embodiments, a portion of the first substrate 210a is removed to thin the first die 20 a. In FIG. 6, the first substrate 210a has a thickness T5, for example, the thickness T5 may be 50 μm. In some embodiments, the first thinning process may be implemented using suitable techniques, such as a grinding process, a polishing process, and/or a chemical etching process.

Referring to fig. 7 and 8, in some embodiments, one or more first openings 260a are formed to expose at least one of the first metal lines 230a, according to a step 508 in fig. 3. In some embodiments, a first photoresist pattern 610 is coated on a first rear surface 214a of the first substrate 210a, and a first etching process is performed to remove the first substrate 210a and the portion of the first interlayer dielectric layer 220a to form the first opening 260 a. In some embodiments, an exposure process and a development process are performed on a first photoresist material completely covering the first back surface 214a to form the first photoresist pattern.

In some embodiments, portions of the first rear surface 214a that are etched are exposed through the first photoresist pattern 610. In some embodiments, the first opening 260a stops at the first metal line 230 a. In some embodiments, the first etching process may etch the first substrate 210a and the first interlayer dielectric layer 220a using a plurality of etchants (etchants) selected according to a material to be etched. In some embodiments, the first substrate 210a and the first interlayer dielectric 220a may be etched using a dry etching process, a wet etching process, a combination thereof, or any other suitable anisotropic etching process. After the first etching process is performed, the first photoresist pattern 610 is removed, for example, by an ashing process or a wet strip process, which chemically changes the first photoresist pattern 610 so that it is not attached to the first substrate 210 a.

Referring to fig. 9, in some embodiments, a first barrier layer (first barrier layer)250a is selectively deposited on the first back surface 214a and in the first opening 260a according to a step 510 in fig. 3. In some embodiments, the first barrier layer 250a is a substantially conformal layer (conformal layer). In some embodiments, the first barrier layer 250a is formed using a Physical Vapor Deposition (PVD) process, for example.

Referring to fig. 10, in some embodiments, a first conductive material 270a is deposited on the first barrier layer 250a according to step 512 of fig. 3. In some embodiments, the first conductive material 270a has a thickness sufficient to fill the first opening 260 a. In some embodiments, the first conductive material 270a is formed by an electroplating process or a Chemical Vapor Deposition (CVD) process.

Referring to fig. 11, in some embodiments, a first planarization process is performed to expose the first substrate 210a according to step 514 of fig. 3. Accordingly, one or more interconnect structures 240a are formed. In some embodiments, the first barrier layer 250a and the first conductive material 270a are planarized to expose the first back surface 214 a. In some embodiments, the first planarization process includes a Chemical Mechanical Polishing (CMP) process and/or a wet etching process.

Referring to fig. 12, in some embodiments, according to a step 516 in fig. 3, a first precursor layer (first precursor layer)280a is deposited to cover the first back surface 214a, the first interconnect structure 240a and the first barrier layer 250 a. In some embodiments, the first precursor layer 280a may be a metal layer containing aluminum, tungsten, cobalt (cobalt), titanium, gold, platinum, or an alloy thereof. In some embodiments, the first precursor layer 280a is formed by a Chemical Vapor Deposition (CVD) process, a Physical Vapor Deposition (PVD) process, a sputtering process, an evaporation process, or an electroplating process.

Next, a first mask 620 is provided over the first precursor layer 280a to pattern the first precursor layer 280 a. In some embodiments, a portion of the first precursor layer 280a is exposed through the first mask 620, and the first interconnect structure 240a is disposed under the first mask 620.

Referring to fig. 13, in some embodiments, according to a step 518 in fig. 3, a first patterning process is performed to etch the first precursor layer 280a through the first mask 620, thereby forming a first re-routing layer 282 a. After the first patterning process is performed, the first mask 620 is removed. In some embodiments, the first redistribution layer 282a is formed by removing the portion of the first precursor layer 280a exposed through the first mask 620. In some embodiments, the first redistribution layer 282a may be located on a central axis C of the first interconnect structure 240a when viewed in cross-section. In some embodiments, the portion of the first redistribution layer 282a covers the first back surface 214 a.

Referring to fig. 14, in some embodiments, according to a step 520 in fig. 3, a first dielectric layer 284a is deposited on the first rear surface 214a exposed by the first redistribution layer 282 a. In some embodiments, a first dielectric layer 284a is disposed around the first redistribution layer 282 a. In some embodiments, the first redistribution layer 282a has a top surface 2822a, and the first dielectric layer 284a has a top surface 2842a, the top surface 2842a and the top surface 2822a are coplanar. In some embodiments, the first dielectric layer 284a is formed using a Chemical Vapor Deposition (CVD) process.

Referring to fig. 15, in some embodiments, a second die 20b is provided according to a step 522 in fig. 3. In some embodiments, the second die 20b has a second substrate 210b, a second interlayer dielectric layer 220b, and a plurality of second metal lines 230b, the second interlayer dielectric layer 220b is disposed on the first substrate 210b, the second metal lines 230b are disposed in the second interlayer dielectric layer 2230b, wherein at least one of the second metal lines 230b is exposed through the second interlayer dielectric layer 220 b. In some embodiments, the second metal line 230b passing through the second interlayer dielectric layer 220b has a top surface 232b, and the top surface 232b is coplanar with a top surface 222b of the second interlayer dielectric layer 220 b. In FIG. 15, the second substrate 210b has a thickness T6, which is about 755 μm.

Next, a second precursor layer 280b is deposited on the top surfaces 222b, 232 b. In some embodiments, the material and method of formation of the second precursor layer 280b is substantially the same as the first precursor layer 280 a.

Further, a first mask 620 is provided over the second precursor layer 280b to define a pattern of a second redistribution layer 282b as shown in fig. 16. In some embodiments, the portion of the second metal line 230b exposed in the second interlayer dielectric layer 220b is deposited under the first mask 620.

Referring to fig. 16, in some embodiments, a second patterning process is performed to etch the second precursor layer 280b, thereby forming a second redistribution layer 282b, according to a step 524 in fig. 3. In some embodiments, the second redistribution layer 282b is formed by removing the portion of the second precursor layer 280b exposed through the first mask 620. After the second patterning process is performed, the first mask 620 is removed. In some embodiments, the first redistribution layer 582a and the second redistribution layer 282b have an identical pattern.

Referring again to fig. 16, in some embodiments, a second dielectric layer 284b is deposited to cover the top surfaces 222b, 232b exposed by the second redistribution layer 282b and to surround the second redistribution layer 282b, in accordance with step 526 of fig. 3. In some embodiments, the second redistribution layer 282b has a top surface 2822b, and the second dielectric layer 284b has a top surface 2842b, the top surface 2842b and the top surface 2822b being coplanar. In some embodiments, the material and formation method of the second dielectric layer 284b are substantially the same as those of the first dielectric layer 284 a.

Referring to fig. 17, in some embodiments, the second die 20b overlaps and bonds the first die 20a in accordance with a step 528 of fig. 3. In some embodiments, the second die 20b is disposed upside down such that the second redistribution layer 282b faces the first redistribution layer 282 a. After the bonding process is performed, the second redistribution layer 282b directly connects the first redistribution layer 282a, thereby forming a first redistribution layer 34, and the second dielectric layer 284b contacts the first dielectric layer 284a, thereby forming a dielectric material 38 between the first die 20a and the second die 20 b. After the first die 20a and the second die 20b are bonded, an annealing process is performed to bond the first redistribution layer 282a to the second redistribution layer 282b and to fuse (fuse) the first dielectric layer 284a to the second dielectric layer 284 b.

Referring to fig. 18, in some embodiments, a second thinning process is performed to thin the second substrate 210b according to step 530 in fig. 3. In some embodiments, a portion of the second substrate 210b is removed to thin the second die 20 b. In FIG. 18, the second substrate 210b has a thickness T7, which is about 50 μm.

Referring to fig. 19, in some embodiments, one or more second openings 290b are formed to expose at least one of the second metal lines 230b according to step 532 in fig. 3. In some embodiments, the second opening 290b is formed by coating a second photoresist pattern 630 on a second back surface 214b disposed opposite to the second front surface 212b and performing a second etching process to remove portions of the second substrate 210b and the second interlayer dielectric layer 220b not covered by the second photoresist pattern 630. After the second etching process is performed, the second photoresist pattern 630 is removed, for example, by an ashing process or a wet stripping process.

Referring to fig. 20, in some embodiments, a second barrier layer 250b may be selectively deposited on the second back surface 214b and in the second opening 290b according to a step 534 in fig. 3. In some embodiments, the second barrier layer 250b has a substantially uniform thickness. The material and formation method of the second barrier layer 250b are substantially the same as those of the first barrier layer 250 a.

Next, according to step 536 of fig. 3, a second conductive material 270b is deposited on the second barrier layer 250 b. In some embodiments, the second conductive material 270b has a thickness sufficient to fill the second opening 290b surrounded by the second barrier layer 250 b. The material and formation method of the second conductive material 270b are substantially the same as those of the first conductive material 270 a.

Referring to fig. 21, in some embodiments, a second planarization process is performed to expose the second substrate 210b, according to step 538 of fig. 3. Accordingly, one or more second interconnect structures 240b are formed. During the second planarization process, portions of the second barrier layer 250b and the second conductive material 270b are removed to expose the second back surface 214 b.

Referring to fig. 22, in some embodiments, a third precursor layer 300 is deposited on the second back surface 214b, the second interconnect structure 240b and the second barrier layer 250b, according to a step 540 in fig. 3. In some embodiments, the material and formation method of the third precursor layer 300 is substantially the same as the first precursor layer 280 a.

Next, as shown in fig. 23, a second mask 640 is provided on the third precursor layer 300. In some embodiments, the second interconnect structure 240b is disposed below the second mask 640.

Referring again to fig. 23, in some embodiments, a third patterning process is performed to etch the third precursor layer 300 through the second mask 640 and expose a portion of the second back surface 214b, according to step 542 of fig. 3. Accordingly, a second redistribution layer 36 is formed. After the third patterning process is performed, the second mask 640 is removed. In some embodiments, the second redistribution layer 36 is formed by removing the portion of the third precursor layer 300 exposed through the second mask 640. In some embodiments, the second redistribution layer 36 covers the portion of the second back surface 214 b.

Next, according to a step 544 in fig. 3, a dielectric layer 38 is deposited to cover the portion of the second back surface 214b exposed by the second redistribution layer 36 and to surround the second redistribution layer 36. In some embodiments, the second redistribution layer 36 has a top surface 362, the dielectric layer 38 has a top surface 382, and the top surface 382 is coplanar with the top surface 362. In some embodiments, the material and formation method of the dielectric layer 38 are substantially the same as those of the first dielectric layer 284a and the second dielectric layer 284 b.

Referring to fig. 24, in some embodiments, one or more Under Bump Metallization (UBM)42 are formed on second redistribution layer 36 and one or more solder bumps 40 are disposed on Under Bump Metallization (UBM)42, in accordance with a step 546 in fig. 3. In some embodiments, the solder bumps 40 are mounted by initially placing a solder flux (not shown) on the Under Bump Metallization (UBM) 42. Soldering fluxes generally have an acidic component (acid component) that removes oxide barriers (oxide barriers) and an adhesion (adhesive quality) that helps prevent movement during processing. Once the solder bumps 40 contact the solder flux, a reflow (reflow) is performed to reflow the solder bumps 40 with the material of the solder flux to fully bond the solder bumps 40 to the Under Bump Metallization (UBM) 42.

Referring to fig. 25, in some embodiments, a grinding process is performed to thin the carrier 30, in accordance with a step 548 in fig. 3. Thus, the semiconductor element 14 is completely formed. In some embodiments, carrier 30 is thinned to a thickness T8, e.g., less than or equal to 50 μm.

An embodiment of the present disclosure provides a semiconductor device. The semiconductor device includes a first die, a second die, a first redistribution layer, a second redistribution layer, a first interconnect structure, and a second interconnect structure. The first die includes a first substrate, a first interlayer dielectric layer disposed on a front surface of the first substrate, and a plurality of first metal lines disposed in the first interlayer dielectric layer. The second die is stacked on the first die and includes a second substrate, a second interlayer dielectric layer disposed on a second front surface of the second substrate, and a plurality of second metal lines disposed in the second interlayer dielectric layer. The first redistribution layer is between the first substrate and the second interlayer dielectric layer. The second redistribution layer is disposed on the second substrate. The first interconnect structure penetrates through the first substrate and penetrates through the first interlayer dielectric layer to connect the first redistribution layer to one of the first metal lines. The second interconnect structure penetrates through the second substrate and into the second interlayer dielectric layer to connect the second redistribution layer to one of the second metal lines.

Another embodiment of the present disclosure provides a method for manufacturing a semiconductor device. The preparation method comprises the following steps: providing a first die comprising a first substrate, a first interlayer dielectric layer disposed on a first front surface of the first substrate, and a plurality of first metal lines disposed in the interlayer dielectric layer; forming a first interconnect structure through the first substrate, through the first interlayer dielectric layer, and contacting one of the first metal lines; forming a first re-routing layer (re-routing layer) completely connecting the first interconnect structure; providing a second die comprising a second substrate, a second interlayer dielectric layer disposed on a second front surface of the second substrate, and a plurality of second metal lines in the second interlayer dielectric layer; forming a second redistribution layer to completely connect one of the second metal lines; stacking the second die on the first die and completely connecting the first redistribution layer to the second redistribution layer; forming a second interconnect structure through the second substrate, through the second interlayer dielectric layer, and contacting one of the second conductive lines; and forming a second redistribution layer on the second substrate and fully connecting the second interconnect structure.

Although the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims. For example, many of the processes described above may be performed in different ways and replaced with other processes or combinations thereof.

Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present disclosure. Accordingly, such processes, machines, manufacture, compositions of matter, means, methods, or steps, are included within the scope of the present application.