阅读说明：本技术 半导体装置及其制造方法 (Semiconductor device and method for manufacturing the same ) 是由 杜卫星 张玉龙 欧阳爵 张铭宏 于 2020-04-10 设计创作，主要内容包括：本公开提供一种半导体装置及其制造方法。所述半导体装置包含衬底、安置于所述衬底上的III-V族层、安置于所述III-V族层上的电介质层,以及从所述电介质层延伸到所述衬底的倾斜侧壁。其中所述衬底包括与所述倾斜侧壁相对地朝向的相对粗糙表面。(The present disclosure provides a semiconductor device and a method of manufacturing the same. The semiconductor device includes a substrate, a group III-V layer disposed on the substrate, a dielectric layer disposed on the group III-V layer, and sloped sidewalls extending from the dielectric layer to the substrate. Wherein the substrate comprises a relatively rough surface facing opposite the sloped sidewalls.)

1. A semiconductor device, comprising:

a substrate;

a III-V layer disposed on the substrate;

a dielectric layer disposed on the III-V layer; and

a sloped sidewall extending from the dielectric layer to the substrate, wherein the substrate comprises a relatively rough surface facing opposite the sloped sidewall.

2. The semiconductor device of claim 1, further comprising a passivation layer covering the sloped sidewalls, wherein the passivation layer comprises an uneven surface facing opposite the sloped sidewalls.

3. The semiconductor device of claim 1, further comprising a passivation layer covering the sloped sidewalls, wherein the passivation layer comprises a relatively smooth surface facing opposite the sloped sidewalls.

4. The semiconductor device of claim 1, wherein a surface of the substrate and the sloped sidewalls define a first angle, and wherein the first angle is in a range of 90 degrees to 150 degrees.

5. The semiconductor device of claim 2, wherein the passivation layer covers an interface between the substrate and the III-V layer.

6. The semiconductor device of claim 2, wherein the uneven surface of the passivation layer is adjacent to an interface between the substrate and the III-V layer.

7. The semiconductor device of claim 2, wherein the first surface of the passivation layer is not coplanar with an interface between the substrate and the III-V layer.

8. The semiconductor device of claim 1, wherein the first surface of the substrate is not coplanar with an interface between the substrate and the III-V layer.

9. The semiconductor device of claim 1, wherein the relatively rough surface of the substrate is oppositely facing an interface between the substrate and the III-V layer.

10. The semiconductor device of claim 2, wherein the uneven surface of the passivation layer is oriented opposite an interface between the substrate and the III-V layer.

11. A semiconductor structure, comprising:

a substrate;

a III-V layer disposed on the substrate;

a dielectric layer disposed on the III-V layer;

a first sidewall extending from the dielectric layer to the substrate; and

a second sidewall disposed opposite the first sidewall and extending from the dielectric layer into the substrate,

wherein the first sidewall and the second sidewall define a groove.

12. The semiconductor structure of claim 11, further comprising a passivation layer, wherein the passivation layer comprises a first portion and a second portion, the first portion covering the first sidewall and the second portion covering a portion of a surface of the substrate.

13. The semiconductor structure of claim 12, wherein the second portion of the passivation layer exposes a portion of a surface of the substrate.

14. The semiconductor structure of claim 12, wherein a first surface of the first portion is not coplanar with an interface between the substrate and the III-V layer.

15. The semiconductor structure of claim 12, wherein the first surface of the substrate is not coplanar with an interface between the substrate and the III-V layer.

16. The semiconductor structure of claim 12, the surface of the substrate and the first sidewall defining a first angle, wherein the first angle is in a range of 90 degrees to 150 degrees.

17. The semiconductor structure of claim 12, the passivation layer further comprising a third portion and a fourth portion, the third portion covering the second sidewall and the fourth portion covering a portion of the surface of the substrate.

18. The semiconductor structure of claim 17, wherein the second portion and the fourth portion define an opening that exposes a portion of the surface of the substrate.

19. A method for fabricating a semiconductor device, comprising:

providing a semiconductor structure having a substrate, a group III-V layer, and a dielectric layer;

forming a recess extending from the dielectric layer to the substrate;

forming a metal layer covering the dielectric layer and the groove;

forming a photoresist layer on the metal layer; and

performing a first photolithography process and a second photolithography process on the photoresist layer; wherein

The focus setting of the first lithography process is different from the focus setting of the second lithography process.

20. The method of claim 19, further comprising:

forming a patterned metal layer; and

forming a passivation layer overlying the patterned metal layer, wherein the passivation layer covers sidewalls of the recess and a portion of the surface of the substrate.

21. The method of claim 20, further comprising:

a singulation process is performed along the grooves, wherein the singulation process passes through the passivation layer.

22. The method of claim 20, wherein the focus setting of the first lithography process is selected according to a top of the groove.

23. The method of claim 20, wherein the focus setting of the second lithography process is selected according to a bottom of the groove.

Technical Field

The present disclosure relates to semiconductor devices and methods of manufacturing the same, and more particularly to semiconductor devices having group III-V layers.

Background

Semiconductor components that include direct bandgap semiconductor materials, such as group III-V materials or group III-V compounds (class: III-V compounds), can operate under a variety of conditions, such as at different voltages and frequencies, due to their properties.

The semiconductor device may include a Heterojunction Bipolar Transistor (HBT), a Heterojunction Field Effect Transistor (HFET), a High Electron Mobility Transistor (HEMT), a modulation-doped fet (modfet), and the like.

Gallium nitride (GaN) is a compound of nitrogen and gallium and is a III-V material that may be used to fabricate III-V semiconductor devices. III-V semiconductor devices may have better electronic properties in terms of saturated electron velocity, high electron mobility, etc.

Disclosure of Invention

In some embodiments of the present disclosure, a semiconductor device is provided. The semiconductor device includes a substrate, a group III-V layer disposed on the substrate, a dielectric layer disposed on the group III-V layer, and sloped sidewalls extending from the dielectric layer to the substrate. Wherein the substrate comprises a relatively rough surface opposite the sloped sidewalls.

In some embodiments of the present disclosure, a semiconductor structure is provided. The semiconductor structure includes a substrate; a III-V layer disposed on a substrate; and a dielectric layer disposed on the III-V layer. The semiconductor structure includes a first sidewall extending from a dielectric layer into a substrate; and a second sidewall disposed opposite the first sidewall and extending from the dielectric layer into the substrate, wherein the first sidewall and the second sidewall define a recess.

In some embodiments of the present disclosure, a method for manufacturing a semiconductor device is provided. The method includes providing a semiconductor structure having a substrate, a III-V layer, and a dielectric layer. The method includes forming a recess extending from a dielectric layer to a substrate, and forming a metal layer overlying the dielectric layer and the recess. The method includes forming a photoresist layer on a metal layer. The method includes performing a first photolithography process and a second photolithography process on a photoresist layer. The focus setting of the first lithography process is different from the focus setting of the second lithography process.

Drawings

Aspects of the present disclosure are readily understood from the following detailed description when read in conjunction with the accompanying drawings. It should be noted that the various features may not be drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

Figure 1A is a simplified schematic cross-sectional view of a portion of a semiconductor wafer, according to certain embodiments of the present disclosure.

Figure 1B is a simplified schematic cross-sectional view of a portion of a semiconductor wafer, according to certain embodiments of the present disclosure.

Figure 1C is a simplified schematic cross-sectional view of a portion of a semiconductor wafer, according to certain embodiments of the present disclosure.

Fig. 2A, 2B, 2C, 2D, 2E, 2F, 2G, and 2H illustrate methods of fabricating semiconductor structures according to some embodiments of the present disclosure.

Fig. 2A, 2B, 2C, 2D, 2E, 2F, 2G, 2H, 2I-1, and 2J-1 illustrate methods of fabricating semiconductor structures according to some embodiments of the present disclosure.

Fig. 2A, 2B, 2C, 2D, 2E, 2F, 2G, 2H, 2I-2, and 2J-2 illustrate methods of fabricating semiconductor structures according to some embodiments of the present disclosure.

Fig. 3A shows a simplified schematic diagram of a plan view of a portion of a wafer including a plurality of semiconductor devices and pre-cut trenches, in accordance with certain embodiments of the present disclosure.

Figure 3B is a simplified schematic cross-sectional view of a portion of a semiconductor wafer, according to certain embodiments of the present disclosure.

Figure 3C shows a portion of a semiconductor device, according to certain embodiments of the present disclosure.

Figure 3D shows a portion of a semiconductor device, according to certain embodiments of the present disclosure.

Figure 3E shows a portion of a semiconductor device, according to certain embodiments of the present disclosure.

Fig. 4A shows a simplified schematic diagram of a plan view of a portion of a wafer including a plurality of semiconductor devices and pre-cut trenches, according to certain comparative embodiments of the present disclosure.

Figure 4B is a simplified schematic cross-sectional view of a portion of a semiconductor wafer, according to certain comparative embodiments of the present disclosure.

Figure 4C shows a portion of a semiconductor device, according to certain comparative embodiments of the present disclosure.

Detailed Description

The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to be limiting. In the present disclosure, references in the following description to the formation of a first feature over or on a second feature may include embodiments in which the first feature is formed in direct contact with the second feature, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. Moreover, 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.

Embodiments of the present disclosure are discussed in detail below. It should be appreciated, however, that the present disclosure provides many applicable concepts that can be embodied in a wide variety of specific contexts. The particular embodiments discussed are merely illustrative and do not limit the scope of the disclosure.

Direct bandgap materials such as III-V compounds may include, but are not limited to, materials such as gallium arsenide (GaAs), indium phosphide (InP), gallium nitride (GaN), indium gallium arsenide (InGaAs), aluminum gallium arsenide (InAlAs), and the like.

Figure 1A is a simplified schematic cross-sectional view of a portion of a semiconductor wafer, according to certain embodiments of the present disclosure.

Fig. 1A shows a semiconductor structure 100 in accordance with certain embodiments of the present disclosure. As shown in fig. 1A, semiconductor structure 100 includes a substrate 10, III-V layers 12 and 14, dielectric layers 16, 18, and 20, a metal layer 22, and a passivation layer 24. The semiconductor structure 100 further comprises a recess 100 t. In some embodiments, the recess 100t may also be referred to as a trench.

Substrate 10 may include, but is not limited to, silicon (Si), doped Si, silicon carbide (SiC), germanium silicide (SiGe), gallium arsenide (GaAs), or other semiconductor materials. Substrate 10 may include, but is not limited to, sapphire, silicon-on-insulator (SOI), or other suitable materials. In some embodiments, the substrate 10 may further include doped regions (not shown in fig. 1A), such as p-wells, n-wells, and the like.

The III-V layers 12 and 14 may be disposed on the substrate 10. The III-V layers 12 and 14 may be stacked on the substrate 10 in some embodiments, the III-V layers 12 and 14 may be doped III-V layers. In some embodiments, the semiconductor structure 100 may include more than two III-V layers. In some embodiments, the semiconductor structure 100 may include only one III-V layer.

III-V layers 12 and 14 may include, but are not limited to, for example, doped gallium nitride (doped GaN), doped aluminum gallium nitride (doped AlGaN), doped indium gallium nitride (doped InGaN), and other doped III-V compounds. The III-V layers 12 and 14 may include, but are not limited to, for example, p-type dopants, n-type dopants, or other dopants. In some embodiments, exemplary dopants may include, for example (but not limited to), magnesium (Mg), zinc (Zn), cadmium (Cd), silicon (Si), germanium (Ge), and the like.

The dielectric layers 16, 18, and 20 may comprise, but are not limited to, for example, an oxide or nitride, such as silicon nitride (SiN), silicon oxide (SiO2), and the like. The dielectric layers 16, 18 and 20 may comprise, for example, but not limited to, a composite layer of oxides and nitrides, such as Al2O3/SiN, Al2O3/SiO2, AlN/SiN, AlN/SiO₂And the like.

In some embodiments, the semiconductor structure 100 may include more than three dielectric layers. In some embodiments, the semiconductor structure 100 may include only one dielectric layer.

A metal layer 22 may be located on the dielectric layer 20. In some embodiments, the metal layer 22 may comprise, but is not limited to, for example, a refractory metal or a compound thereof. For example, the metal layer 22 may include, but is not limited to, for example, niobium (Nb), molybdenum (Mo), tantalum (Ta), tungsten (W), rhenium (Re), titanium (Ti), vanadium (V), chromium (Cr), zirconium (Zr), hafnium (Hf), ruthenium (Ru), osmium (Os), iridium (Ir), and other metals, or compounds of these metals, such as tantalum nitride (TaN), titanium nitride (TiN), tungsten carbide (WC), and the like.

A passivation layer 24 may be disposed on the dielectric layer 20. A passivation layer 24 may be disposed on the metal layer 22. The passivation layer 24 may cover at least a portion of the dielectric layer 20. The passivation layer 24 may cover at least a portion of the metal layer 22.

Referring to fig. 1A, a recess 100t extends from dielectric layer 20 to substrate 10. The passivation layer 24 may be disposed to cover the sidewalls 100w of the groove 100 t. The passivation layer 24 may be disposed to cover the surface 10s of the substrate 10.

The semiconductor structure 100 may include one or more contacts. In some embodiments, the semiconductor structure 100 may include a metal contact 18c1 disposed within the dielectric layers 16 and 18. In some embodiments, the semiconductor structure 100 may include a metal contact 18c2 disposed within the dielectric layers 16 and 18. In some embodiments, the semiconductor structure 100 may include a metal contact 20c1 disposed within the dielectric layer 20. In some embodiments, the semiconductor structure 100 may include a metal contact 20c2 disposed within the dielectric layer 20.

The semiconductor structure 100 may include one or more interlayer connection elements. In some embodiments, the semiconductor structure 100 may include an interlayer connection element 18v1 electrically connected between the metal contact 18c1 and the metal contact 20c 1. In some embodiments, the semiconductor structure 100 may include an interlayer connection element 18v2 electrically connected between the metal contact 18c2 and the metal contact 20c 2. In some embodiments, the semiconductor structure 100 may include an interlayer connection element 20v1 electrically connected between the metal contact 20c1 and the metal layer 22. In some embodiments, the semiconductor structure 100 may include an interlayer connection element 20v2 electrically connected between the metal contact 20c2 and the metal layer 22.

Each of the interlayer connection elements 18v1, 18v2, 20v1, and 20v2 may be referred to as a through hole.

Referring to fig. 1A, a semiconductor structure 100 includes regions 100A, 100B, and 100C. Region 100A may be referred to as a scribe line or scribe area. The semiconductor structure 100 may be divided or separated along the region 100A into a number of semiconductor devices (not shown in fig. 1A, which may include the structures in regions 100B and 100C) by a dicing/sawing technique.

Techniques that may be used to cut/saw the semiconductor structure 100 include, but are not limited to, mechanical cutting or sawing, laser ablation or laser grooving, plasma cutting, wet or dry etching of trenches or trenches, and/or laser induced cracking/splitting.

The region 100B may include a protective structure (e.g., a seal ring). For example, a seal ring may be disposed around the integrated circuit (which may be disposed in region 100C) to implement protection. For example, when dicing techniques are applied to these semiconductor structures 100 along the region 100A, the seal ring in the region 100B may prevent the propagation of cracks (which may emerge from the dicing region 100A) in order to protect the structures within the region 100C.

The structure comprising the metal contact 18C1, the interlayer connection element 18v1, the metal contact 20C1, the interlayer connection element 20v1, and the metal layer 22 may have a metal, alloy, or other suitable material to protect the circuitry (e.g., internal circuitry within the region 100C) from damage.

The structure comprising the metal contact 18C2, the interlayer connection element 18v2, the metal contact 20C2, the interlayer connection element 20v2, and the metal layer 22 may have a metal, alloy, or other suitable material to protect the circuitry (e.g., internal circuitry within the region 100C) from damage.

Region 100C may be an area occupied by a circuit or integrated circuit. Region 100C may be referred to as an active device region.

A relatively thin portion (not shown in fig. 1A) below the recess 100t in the region 100A of the semiconductor structure 100 may save costs. For example, the time for a dicing/sawing operation on the semiconductor structure 100 may be reduced. For example, power consumed by the cutting/sawing operation may be minimized. For example, the life of a cutting tool (e.g., a knife or a blade of a knife) may be extended.

The relatively thin portion (not shown in fig. 1A) under the recess 100t in the region 100A of the semiconductor structure 100 also resists cracking or delamination. The separation process performed within the recess 100t does not pass through an interlayer interface (e.g., the interface between the substrate 10 and the III-V layer 12), and thus cracking or delamination caused by lattice mismatch can be avoided.

The lattice mismatch between the substrate 10 and the III-V layer 12 may render the interface between the substrate 10 and the III-V layer 12 susceptible to damage when dicing techniques are applied to the semiconductor structure 100. The passivation layer 24 defining the recess 100t in the region 100A may cover the interface between the substrate 10 and the III-V layer 12 for protection. Therefore, the yield of manufacturing can be improved. For example, cracks or delamination due to the cutting operation may be prevented from propagating at the interface between the substrate 10 and the passivation layer 24 by the passivation layer 24 covering the sidewalls of the substrate 10 and the III-V layer 12.

Figure 1B is a simplified schematic cross-sectional view of a portion of a semiconductor wafer, according to certain embodiments of the present disclosure.

Fig. 1B shows a semiconductor structure 100' in accordance with certain embodiments of the present disclosure. As shown in fig. 1B, semiconductor structure 100 'includes substrate 10, III-V layers 12 and 14, dielectric layers 16, 18 and 20, metal layer 22, and passivation layer 24'. The semiconductor structure 100' further includes a recess 100 t. In some embodiments, the recess 100t may also be referred to as a trench.

The semiconductor structure 100' shown in fig. 1B is similar to the semiconductor structure 100 shown in fig. 1A, except that the passivation layer 24' of the semiconductor structure 100' includes an opening 24h1 near the bottom of the recess 100 t. The opening 24h1 exposes a portion of the bottom of the groove 100 t. The opening 24h1 exposes a portion of the substrate 10. The opening 24h1 exposes a portion of the surface 10s of the substrate 10.

Referring to fig. 1B, the passivation layer 24' includes a portion 24a disposed on the surface 10s of the substrate 10. The passivation layer 24' includes a portion 24b disposed on the surface 10s of the substrate 10. Opening 24h1 may be defined by portion 24a and portion 24 b.

The semiconductor structure 100' may be cut/sawed along the opening 24h 1. Cutting/sawing the semiconductor structure 100' along the opening 24h1 may provide a number of benefits. For example, the portion of the substrate 10 exposed by the opening 24h1 has a smaller thickness than other portions of the semiconductor structure 100', and cutting/sawing the semiconductor structure 100' along the opening 24h1 may reduce the cost of the overall manufacturing process.

Furthermore, cutting/sawing the semiconductor structure 100' along the opening 24h1 involves only cutting/sawing the substrate 10, which is a single layer structure. Therefore, no cracking or delamination is introduced in the manufacturing process.

In some embodiments, the opening 24h1 may be utilized as an alignment mark during a pre-cutting procedure of the semiconductor structure 100'. In some embodiments, the openings 24h1 may increase the accuracy of the pre-cutting procedure. In some embodiments, the opening 24h1 may increase the speed of the pre-cutting procedure. In some embodiments, the openings 24h1 may improve the yield of the semiconductor structure 100'.

Reference is now made to the dotted circle a shown in fig. 1B. In some embodiments, portion 24a covers corner 100r of groove 100 t. In some embodiments, portion 24a covers interface 10i between substrate 10 and III-V layer 12. The portion 24a may prevent moisture from entering the interface 10i between the substrate 10 and the III-V layer 12. The portion 24a prevents contaminants from entering the interface 10i between the substrate 10 and the III-V layer 12. In addition, the portion 24a can prevent cracks or delamination due to the dicing operation from spreading at the interface between the substrate 10 and the passivation layer 24.

Figure 1C is a simplified schematic cross-sectional view of a portion of a semiconductor wafer, according to certain embodiments of the present disclosure.

Fig. 1C shows a semiconductor structure 100 "in accordance with certain embodiments of the present disclosure. As shown in fig. 1C, semiconductor structure 100 "comprises substrate 10, III-V layers 12 and 14, dielectric layers 16, 18 and 20, metal layer 22, and passivation layer 24". The semiconductor structure 100 "further comprises a recess 100 t. In some embodiments, the recess 100t may also be referred to as a trench.

The semiconductor structure 100 "shown in fig. 1C is similar to the semiconductor structure 100 shown in fig. 1A, except that the passivation layer 24" of the semiconductor structure 100 "includes an opening 24h 2. The opening 24h2 exposes a portion of the bottom of the groove 100 t. The opening 24h2 exposes a portion of the substrate 10. The opening 24h2 exposes a portion of the surface 10s of the substrate 10.

The recess 100t may include sloped sidewalls 100 w. The sidewalls 100w may include sidewalls 12w, 14w, 16w, 18w, and 20 w. The sidewall 100w is adjacent to the region 100B including the protection structure. The sidewall 12w connects the III-V layer 14 and the substrate 10. The sidewalls 14w connect the group III-V layer 12 and the dielectric layer 16. The sidewalls 16w connect the group III-V layer 14 and the dielectric layer 18. Sidewalls 18w connect dielectric layer 16 and dielectric layer 20. Sidewalls 100w extend from dielectric layer 20 to substrate 10. The sidewall 100w connects the upper surface 24s "of the passivation layer 24" to the surface 10s of the substrate 10.

The groove 100t may include sloped sidewalls 100w 2. The side wall 100w2 may include side walls 12w2, 14w2, 16w2, 18w2 and 20w 2. The sidewall 100w2 is adjacent to the region 100B containing the protection structure.

The opening 24h2 exposes the sidewall 100w of the recess 100 t. As shown in fig. 1C, the sidewalls 12w of the III-V layer 12 are exposed. The sidewalls 14w of the III-V layer 14 are exposed. The sidewalls 16w of the dielectric layer 16 are exposed. Sidewalls 18w of dielectric layer 18 are exposed. Sidewalls 20w of dielectric layer 20 are exposed.

The semiconductor structure 100 "may be cut/sawed along the grooves 100 t. As previously discussed, cutting/sawing the semiconductor structure 100 "along the grooves 100t may bring a number of benefits. In some embodiments, the recess 100t may be utilized as an alignment mark during a pre-dicing process of the semiconductor structure 100 ". In some embodiments, the groove 100t may increase the accuracy of the pre-cutting procedure. In some embodiments, the groove 100t may increase the speed of the pre-cutting procedure. In some embodiments, the recess 100t may improve yield of the semiconductor structure 100 ".

Fig. 2A, 2B, 2C, 2D, 2E, 2F, 2G, and 2H illustrate methods of fabricating semiconductor structures according to some embodiments of the present disclosure.

The operations shown in fig. 2A, 2B, 2C, 2D, 2E, 2F, 2G, and 2H may be used to produce a semiconductor structure similar to the semiconductor structure 100 shown in fig. 1A.

Referring to fig. 2A, a substrate 10 is provided and III-V layers 12 and 14 are disposed on an upper surface of the substrate 10. Dielectric layers 16, 18, and 20 are then disposed on the upper surface of the III-V layer 14. A patterned photoresist layer 30 is provided (e.g., formed) on the dielectric layer 20. The patterned photoresist layer 30 defines an opening 30 h. The opening 30h exposes a portion of the dielectric layer 20. The opening 30h exposes the surface 20s of the dielectric layer 20.

Referring to fig. 2B, portions of substrate 10, III-V layers 12 and 14, and dielectric layers 16, 18, and 20 are removed and a recess 100t is formed. Subsequently, the patterned photoresist layer 30 is then removed.

In some embodiments, the groove 100t may be formed by an etching process. In some embodiments, the groove 100t may be formed by dry etching, wet etching, or a combination of dry etching and wet etching. In some embodiments, the groove 100t may be formed by laser ablation or laser grooving. In some embodiments, the groove 100t may be formed by any other suitable technique.

An angle θ exists between the sidewall 100w and the surface 10s of the substrate 10. The angle θ varies depending on the technique used to form the groove 100 t.

In some embodiments, the angle θ is in the range of 90 degrees to 100 degrees. In some embodiments, the angle θ is in the range of 100 degrees to 110 degrees. In some embodiments, the angle θ is in the range of 110 degrees to 120 degrees. In some embodiments, the angle θ is in the range of 120 degrees to 130 degrees. In some embodiments, the angle θ is in the range of 130 degrees to 140 degrees. In some embodiments, the angle θ is in the range of 140 degrees to 150 degrees. In some embodiments, the angle θ is in the range of 90 degrees to 150 degrees.

Referring to fig. 2C, a metal layer 22 is formed on the dielectric layer 20 and the recess 100 t. A metal layer 22 covers the upper surface of the dielectric layer 20. The metal layer 22 covers the sidewalls 100w of the recess 100 t. The metal layer 22 covers the surface 10s of the substrate 10.

In some embodiments, the metal layer 22 may be formed by Physical Vapor Deposition (PVD), Chemical Vapor Deposition (CVD), Atomic Layer Deposition (ALD), plating, and/or other suitable deposition steps.

Referring to fig. 2D, a photoresist layer 31 is provided (e.g., formed) on the metal layer 22. A photoresist layer 31 may be conformally formed on the metal layer 22.

Referring to fig. 2E, a photolithography process is performed to remove certain portions of the photoresist layer 31 in order to form a patterned photoresist layer. After the photolithography process, portions 31a, 31b, 31c and 31d of the photoresist layer 31 remain.

Among the portions 31a, 31b, 31c and 31d, the portions 31a and 31b are required, while the portions 31b and 31c should be removed.

If the portions 31b and 31c are not removed, the portions of the metal layer 22 under the portions 31b and 31c cannot be removed in a subsequent process and thus will remain in the recess 100 t. The remaining metal layer will be located around the bottom corner of the recess 100 t. The remaining metal layer within the recess 100t may adversely affect the dicing/sawing process of the semiconductor structure. For example, the remaining metal layer within the groove 100t may cause damage to a wafer sawing/cutting machine used to cut/saw the wafer via the groove 100 t.

The portions 31b and 31c may result from the focus setting of the lithographic apparatus used. That is, because the groove 100t has a depth, if focus is set according to the top of the groove 100t, the photoresist layer 31 at the bottom of the groove 100t will fall out of focus. On the other hand, if the focus is set according to the bottom of the groove 100t, the photoresist layer 31 around the top of the groove 100t will fall out of focus.

To create a patterned photoresist layer extending from the top to the bottom of the groove, a two-step photolithography process is proposed (that is, the operations shown in fig. 2E and 2F).

Referring to fig. 2F, a photolithography process is performed to remove portions 31b and 31 c. The remaining portions 31a and 31d may be referred to as a patterned photoresist layer 31'. In some embodiments, the focus used in the operation shown in fig. 2E is different from the focus used in the operation shown in fig. 2F. In some embodiments, the focus used in the operation shown in fig. 2E is shorter than the focus used in the operation shown in fig. 2F.

In some embodiments, the focus used in the operation shown in fig. 2E is selected according to the distance between the top of the groove 100t and the lithographic apparatus. In some embodiments, the focus used in the operation shown in fig. 2F is selected according to the distance between the bottom of the groove 100t and the lithographic apparatus.

Referring to fig. 2G, a portion of the metal layer 22 is removed. Subsequently, the patterned photoresist layer 31' is removed. The remaining portion of the metal layer 22 may also be referred to as a patterned metal layer.

Referring to fig. 2H, a passivation layer 24 is formed on the metal layer 22 and the groove 100 t. The passivation layer 24 may be conformally formed along the sidewalls of the groove 100 t.

Fig. 2A, 2B, 2C, 2D, 2E, 2F, 2G, 2H, 2I-1, and 2J-1 illustrate methods of fabricating semiconductor structures according to some embodiments of the present disclosure.

The operations shown in fig. 2A, 2B, 2C, 2D, 2E, 2F, 2G, 2H, 2I-1, and 2J-1 may be used to produce a semiconductor structure similar to the semiconductor structure 100 shown in fig. 1B.

The operations shown in FIG. 2I-1 may be performed after the operations shown in FIG. 2H. Referring to fig. 2I-1, a patterned photoresist layer 32 is formed on the passivation layer 24. Patterned photoresist layer 32 includes opening 32h1 near the bottom of groove 100 t. The opening 32h1 exposes a portion of the passivation layer 24. The opening 32h1 exposes the surface 24s of the passivation layer 24.

The operations shown in FIG. 2J-1 may be performed after the operations shown in FIG. 2I-1. Referring to fig. 2J-1, a portion of passivation layer 24 is removed, and patterned photoresist layer 32 is subsequently removed. The operation shown in fig. 2J-1 creates opening 24h1 from passivation layer 24. The opening 24h1 exposes a portion of the substrate 10. The opening 24h1 exposes the surface 10s of the substrate 10.

Fig. 2A, 2B, 2C, 2D, 2E, 2F, 2G, 2H, 2I-2, and 2J-2 illustrate methods of fabricating semiconductor structures according to some embodiments of the present disclosure.

The operations shown in fig. 2A, 2B, 2C, 2D, 2E, 2F, 2G, 2H, 2I-2, and 2J-2 may be used to produce a semiconductor structure similar to the semiconductor structure 100 shown in fig. 1C.

The operations shown in fig. 2I-2 may be performed after the operations shown in fig. 2H. Referring to fig. 2I-2, a patterned photoresist layer 32 is formed on the passivation layer 24. Patterned photoresist layer 32 includes openings 32h 2. The opening 32h2 exposes a portion of the passivation layer 24.

The operations shown in fig. 2J-2 may be performed after the operations shown in fig. 2I-2. Referring to fig. 2J-2, a portion of the passivation layer 24 is removed, and the patterned photoresist layer 32 is subsequently removed. The operation shown in fig. 2J-2 creates opening 24h2 from passivation layer 24. The opening 24h2 exposes the recess 100 t. The opening 24h2 exposes the sidewall 100w of the recess 100 t. The opening 24h2 exposes a portion of the substrate 10. The opening 24h1 exposes the surface 10s of the substrate 10.

Fig. 3A shows a simplified schematic diagram of a plan view of a portion of a wafer including a plurality of semiconductor devices and pre-cut trenches, in accordance with certain embodiments of the present disclosure.

Referring to fig. 3A, a wafer 40 includes semiconductor devices 42d1, 42d2, 42d3, and 42d 4. The semiconductor device 42d1 includes a seal ring 42s1 around the perimeter of the semiconductor device 42d 1. The semiconductor device 42d2 includes a seal ring 42s2 around the perimeter of the semiconductor device 42d 2. The semiconductor device 42d3 includes a seal ring 42s3 around the perimeter of the semiconductor device 42d 3. The semiconductor device 42d4 includes a seal ring 42s4 around the perimeter of the semiconductor device 42d 4.

The groove 100t is disposed between the semiconductor device 42d1 and the semiconductor device 42d 2. The groove 100t is disposed between the semiconductor device 42d1 and the semiconductor device 42d 3. The groove 100t is disposed between the semiconductor device 42d2 and the semiconductor device 42d 4. The groove 100t is disposed between the semiconductor device 42d3 and the semiconductor device 42d 4. The semiconductor devices 42d1, 42d2, 42d3 and 42d4 may be separated by sawing the wafer 40 along the grooves 100 t.

In some embodiments, the grooves 100t have a width of about 40 micrometers (μm). In some embodiments, region 100A has a width of about 40 μm.

Figure 3B is a simplified schematic cross-sectional view of a portion of a semiconductor wafer, according to certain embodiments of the present disclosure. The semiconductor structure 100d of fig. 3B may be a cross-sectional view of a portion of the wafer 40 along the dotted line a-a' of fig. 3A.

Figure 3C shows a portion of a semiconductor device, according to certain embodiments of the present disclosure.

Fig. 3C shows a portion of a semiconductor device 42d 1. The semiconductor device 42d1 may be singulated from the wafer 40. In some embodiments, the semiconductor devices 42d1 may be singulated from the wafer 40 using a metal blade. In some embodiments, the semiconductor device 42d1 may be singulated from the wafer 40 using a water-cooled circular saw with diamond tines.

Referring to dotted circle B shown in fig. 3C, the upper surface 24s of the passivation layer 24 may not be coplanar with the interface 10 i. Also, the upper surface 10s of the substrate 10 may not be coplanar with the interface 10 i. As previously discussed with respect to FIG. 1B, the configuration of portion 24a includes several advantages. For example, the portion 24a may prevent moisture from entering the interface 10i between the substrate 10 and the III-V layer 12. The portion 24a prevents contaminants from entering the interface 10i between the substrate 10 and the III-V layer 12. In addition, the crack or delamination due to the cutting operation can be prevented from spreading on the interface between the substrate 10 and the passivation layer 24 by the portion 24 a.

Referring again to the dotted circle B shown in fig. 3C, a blade or saw used to singulate the semiconductor devices 42d1 may pass through the passivation layer 24 and introduce an uneven edge to the passivation layer 24. A blade or saw used to singulate the semiconductor devices 42d1 may introduce an uneven edge to the substrate 10.

As shown in dotted circle B, the passivation layer 24 may have a relatively rough surface 24w1 adjacent to the substrate 10. The passivation layer 24 may have a relatively uneven surface 24w1 adjacent to the substrate 10. The passivation layer 24 may have a relatively rough surface 24w1 adjacent to the interface 10 i. The passivation layer 24 may have a relatively uneven surface 24w1 adjacent to the interface 10 i. The passivation layer 24 may have a relatively rough surface 24w1 facing opposite the interface 10 i. The passivation layer 24 may have a relatively uneven surface 24w1 facing opposite the interface 10 i. The passivation layer 24 may have a relatively rough surface 24w1 adjacent to the sidewall 100 w. The passivation layer 24 may have an uneven surface 24w1 facing opposite the sidewall 100 w. The passivation layer 24 may have a relatively rough surface 24w1 facing opposite the sidewall 100 w.

The substrate 10 may have a relatively rough surface 10w adjacent to the interface 10 i. The substrate 10 may have a relatively uneven surface 10w adjacent to the interface 10 i. Substrate 10 may have a relatively rough surface 10w facing opposite/away from interface 10 i. The substrate 10 may have a relatively uneven surface 10w facing opposite/back to the interface 10 i. The substrate 10 may have a relatively rough surface 10w adjacent to the sidewalls 100 w. The substrate 10 may have a relatively uneven surface 10w facing opposite/away from the sidewall 100 w.

Figure 3D shows a portion of a semiconductor device, according to certain embodiments of the present disclosure. Fig. 3D shows a portion of a semiconductor device 42D 1'. The semiconductor device 42d1' may be singulated from the wafer 40.

Referring to the dotted circle C shown in fig. 3D, a blade or saw used to divide the semiconductor device 42D1' introduces an uneven edge to the substrate 10. The blade or saw used to singulate the semiconductor devices 42d1' does not pass through the passivation layer 24 and therefore does not introduce uneven edges into the passivation layer 24.

As shown in dotted circle C, the passivation layer 24 may have a relatively smooth surface 24w2 adjacent to the substrate 10. Passivation layer 24 may have a relatively smooth surface 24w2 adjacent interface 10 i. Passivation layer 24 may have a relatively smooth surface 24w2 facing opposite interface 10 i. The passivation layer 24 may have a relatively smooth surface 24w2 facing opposite the sidewall 100 w.

The substrate 10 may have a relatively rough surface 10w adjacent to the interface 10 i. The substrate 10 may have a relatively uneven surface 10w adjacent to the interface 10 i. The substrate 10 may have a relatively rough surface 10w facing opposite the interface 10 i. The substrate 10 may have a relatively uneven surface 10w facing opposite the interface 10 i.

Figure 3E shows a portion of a semiconductor device, according to certain embodiments of the present disclosure. Fig. 3E shows a portion of the semiconductor device 42d1 ". The semiconductor device 42d1 "may be singulated from the wafer 40.

Referring to the dotted circle D shown in fig. 3E, a blade or saw used to divide the semiconductor device 42D1' may introduce uneven edges to the substrate 10. The substrate 10 may have a relatively rough surface 10w adjacent to the interface 10 i. The substrate 10 may have a relatively uneven surface 10w adjacent to the interface 10 i. The substrate 10 may have a relatively rough surface 10w facing opposite the interface 10 i. The substrate 10 may have a relatively uneven surface 10w facing opposite the interface 10 i. The substrate 10 may have a relatively rough surface 10w facing opposite the sidewall 100 w.

Fig. 4A shows a simplified schematic diagram of a plan view of a portion of a wafer including a plurality of semiconductor devices and pre-cut trenches, according to certain comparative embodiments of the present disclosure.

Referring to fig. 4A, a wafer 60 includes semiconductor devices 62d1, 62d2, 62d3, and 62d 4. The semiconductor device 62d1 includes a seal ring 62s1 around the perimeter of the semiconductor device 62d 1. The semiconductor device 62d2 includes a seal ring 62s2 around the perimeter of the semiconductor device 62d 2. The semiconductor device 62d3 includes a seal ring 62s3 around the perimeter of the semiconductor device 62d 3. The semiconductor device 62d4 includes a seal ring 62s4 around the perimeter of the semiconductor device 62d 4.

The groove 62t1 surrounds the periphery of the seal ring 62s 1. The groove 62t2 surrounds the periphery of the seal ring 62s 2. The groove 62t3 surrounds the periphery of the seal ring 62s 3. The groove 62t4 surrounds the periphery of the seal ring 62s 4.

Figure 4B is a simplified schematic cross-sectional view of a portion of a semiconductor wafer, according to certain comparative embodiments of the present disclosure.

Fig. 4B shows a semiconductor structure 200 in accordance with certain comparative embodiments of the present disclosure. The semiconductor structure 200 of fig. 4B may be a cross-sectional view of a portion of the wafer 60 along the dotted line B-B' of fig. 4A.

Semiconductor device 200 includes regions 200A, 200B, and 200C. Region 200A may be referred to as a scribe line or scribe area. Semiconductor devices (not shown) included in the semiconductor device 200 may be separated or singulated by cutting/sawing the semiconductor device 200 along the regions 200A. Region 200B is a seal ring and region 200C is a region in which a semiconductor device (not shown) is located, and may be referred to as an active device region.

Semiconductor structure 200 includes a groove 200t1 disposed adjacent to one side of region 200A and a groove 200t2 disposed adjacent to the other side of region 200A.

Referring to region 200A of fig. 4B, this region of the semiconductor structure 200 comprises a multilayer structure. Thus, the blade or saw used in the singulation process will necessarily pass through several interfaces. For example, dicing/sawing along region 200A will pass through interface 10i between substrate 10 and III-V layer 12. Because of the lattice mismatch between the substrate 10 and the III-V layer 12, cutting through the interface 10i tends to cause cracking or delamination. According to the embodiment shown in fig. 4B, cracks 12C may form from the interface 10i and diffuse toward the direction of the regions 200B and 200C. Cracking or delamination resulting from the cutting/sawing along the region 200A will adversely affect the yield of the overall manufacturing process.

Referring to both fig. 4A and 4B, the groove 62t1 shown in fig. 4A may correspond to the groove 200t1 shown in fig. 4B. The groove 62t3 shown in fig. 4A may correspond to the groove 200t2 shown in fig. 4B. The seal rings 62s1 and 62s3 shown in fig. 4A may correspond to the region 200B shown in fig. 4B. The semiconductor devices 62d1 and 62d3 shown in fig. 4A may be positioned in the region 200C of fig. 4B.

In some embodiments, grooves 200t1, region 200A, and grooves 200t2 have a total width of about 80 μm. In some embodiments, grooves 200t1, region 200A, and grooves 200t2 have a total width of about 120 μm. In some embodiments, the total width of groove 200t1, region 200A, and groove 200t2 is in the range of 80 μm to 120 μm.

Due to the widths of groove 200t1, region 200A, and groove 200t2, the effective usable area of wafer 60 shown in fig. 4A is less than the effective usable area of wafer 40 shown in fig. 3A. In some embodiments, the effective usable area of wafer 60 may be 30% less than the effective usable area of wafer 40. In some embodiments, the effective usable area of wafer 60 may be up to 40% smaller than the effective usable area of wafer 40. Here, the effective use area refers to a percentage of the total area of the wafer occupied by the semiconductor device.

Figure 4C shows a portion of a semiconductor device, according to certain comparative embodiments of the present disclosure.

Fig. 4C shows a portion of the semiconductor device 62d 1. The semiconductor device 62d1 may be singulated from the wafer 60. In some embodiments, the semiconductor devices 62d1 may be singulated from the wafer 60 using a blade, saw, or laser. Referring to fig. 4C, the semiconductor device 62d1 includes a groove 200t 1. The passivation layer 24 may extend toward the groove 200t1 and cover the sidewalls of the groove 200t 1.

As used herein, spatial relationship terms, such as "below," "lower," "above," "upper," "lower," "left," "right," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as shown in the figures. The spatial relationship 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 spatial relationship descriptors used herein interpreted accordingly as well. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present.

As used herein, the terms "approximately," "substantially," and "about" are used to describe and account for minor variations. When used in conjunction with an event or circumstance, the terms can refer to the exact occurrence of the event or circumstance as well as the fact that the event or circumstance occurs in close proximity. As used herein with respect to a given value or range, the term "about" generally means within ± 10%, ± 5%, ± 1%, or ± 0.5% of the given value or range. Ranges may be expressed herein as from one end point to the other end point or between the two end points. Unless otherwise specified, all ranges disclosed herein are inclusive of the endpoints. The term "substantially coplanar" may refer to two surfaces located within a few micrometers (μm) along the same plane, such as within 10 μm, within 5 μm, within 1 μm, or within 0.5 μm located along the same plane. When referring to "substantially" the same numerical value or property, the term can refer to a value that is within ± 10%, ± 5%, ± 1%, or ± 0.5% of the mean of the stated values.

The foregoing has outlined features of several embodiments and detailed aspects of the present disclosure. The embodiments described in this disclosure may be readily utilized as a basis for designing or modifying other processes and structures for carrying out the same or similar purposes and/or achieving the same or similar advantages of the embodiments introduced herein. Such equivalent constructions do not depart from the spirit and scope of the present disclosure, and various changes, substitutions, and alterations may be made therein without departing from the spirit and scope of the present disclosure.