A bonding structure and a bonding method

Abstract

The present disclosure discloses a bonding structure, comprising a first bonding layer and a second bonding layer, wherein the first bonding layer comprises a first bonding surface; the first bonding surface comprises a first locking structure with a protruding structure; the second bonding layer comprises a second bonding surface; the second bonding surface comprises a second locking structure with a cavity structure corresponding to the protruding structure and used for accommodating the protruding structure; and the first locking structure and the second locking structure form an interlocking structure when bonded. The bonding structure of the present disclosure can withstand a larger bonding pressure, effectively improve the bonding quality and firmness while reducing the bonding pressure sensitivity, and has a broad application prospect in the field of semiconductors.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of semiconductor manufacturing, and more particularly, to a bonding structure with interlocking structure and a bonding method. BACKGROUND

[0002] The current main bonding methods include thermal ultrasonic bonding, thermal compression bonding and surface modification bonding, and the two bonding surfaces are in contact in a face-to-face manner during bonding. Referring to the attached drawings, the bonding process of the thermal ultrasonic bonding is shown in FIG. 1, the bonding process of the thermal compression bonding is shown in FIG. 2, and the bonding process of the surface modification bonding is shown in FIG. 3. Figure 1 In order to improve the bonding quality and firmness after bonding, a groove is generally formed on one of the bonding surfaces in the prior art, because the bonding metal will overflow due to extrusion during the bonding process after bearing the bonding temperature and pressure, and the groove on the bonding surface can accommodate the overflow of the metal, thereby preventing the metal from overflowing due to extrusion during the bonding process.

[0003] The existing bonding technology still has the following problems: In order to avoid excessive overflow of the bonding metal, a smaller bonding pressure and temperature are used, which results in lower bonding quality and firmness. If the bonding pressure and temperature are increased in order to ensure the bonding quality, the application of the bonding will be limited, and the high temperature and pressure make it impossible to achieve the bonding of wafers with devices and the bonding of thinner chips in the semiconductor manufacturing process, and the high bonding pressure and temperature will also generate a reaction force in the groove, which will also reduce the bonding quality and firmness.

[0004] The present disclosure is designed to solve the above technical problems, and a novel bonding structure is designed by improving the bonding surface, especially by forming an interlocking structure through the cooperative action of the two bonding surfaces, so that the bonding structure of the present disclosure can withstand a larger bonding pressure, effectively improve the bonding quality and firmness while reducing the bonding pressure sensitivity, and has a broad application prospect in the field of semiconductors. SUMMARY

[0005] In the following, a brief overview of the present disclosure will be given in order to provide a basic understanding of some aspects of the present disclosure. It should be understood that this overview is not an exhaustive overview of the present disclosure. It is not intended to determine the key or important parts of the present disclosure, nor to limit the scope of the present disclosure. Its purpose is only to give some concepts in a simplified form as a prelude to the more detailed description discussed later.

[0006] According to an aspect of the present disclosure, a bonding structure is provided, comprising a first bonding layer and a second bonding layer, wherein the first bonding layer comprises a first bonding surface; the first bonding surface comprises a first locking structure having a protrusion structure; the second bonding layer comprises a second bonding surface; the second bonding surface comprises a second locking structure having a cavity structure corresponding to the protrusion structure and configured to accommodate the protrusion structure; and the first locking structure and the second locking structure form an interlocking structure when bonded.

[0007] Further, wherein the protrusion structure comprises an end portion away from the first bonding surface and a connecting portion connecting the end portion and the first bonding surface, the end portion having a width greater than the connecting portion in a direction along the first bonding surface; and the cavity structure comprises a first opening portion away from the second bonding surface and a second opening portion between the second bonding surface and the first opening portion, the first opening portion having a width less than the second opening portion in a direction along the second bonding surface.

[0008] Further, wherein the end portion of the protrusion structure overflows outwardly and the first opening portion of the cavity structure overflows inwardly to form the interlocking structure when bonded.

[0009] Further, wherein the width of the end portion is less than the width of the first opening portion.

[0010] Further, wherein the end portion and the connecting portion form an inverted T-shaped structure, and the first opening portion and the second opening portion form a convex-shaped cavity structure.

[0011] Further, wherein the first bonding layer and the second bonding layer comprise at least one of Au, Al, Si, Ge, Ni, Cu and alloys thereof.

[0012] Further, wherein the first bonding layer or the second bonding layer has a thickness of 1000 nm-4000 nm and a surface uniformity less than 5%.

[0013] According to an aspect of the present disclosure, a bonding method is provided, comprising the steps of: forming a first bonding layer on a first substrate, the first bonding layer comprising a first bonding surface, the first bonding surface comprising a first locking structure having a protrusion structure; forming a second bonding layer on a second substrate, the second bonding layer comprising a second bonding surface, the second bonding surface comprising a second locking structure having a cavity structure corresponding to the protrusion structure and configured to accommodate the protrusion structure; and bonding the first substrate and the second substrate, the first locking structure and the second locking structure forming an interlocking structure when bonded.

[0014] Further, the step of forming the first bonding layer comprises: depositing a first bonding material layer on the first substrate, performing photolithography after forming a first photoresist layer on the first bonding material layer; and depositing a second bonding material layer on the first substrate, forming a first bonding surface with the first locking structure on the first substrate after stripping the first photoresist layer.

[0015] Further, the step of forming the second bonding layer comprises: depositing a third bonding material layer on the second substrate, performing photolithography after forming a second photoresist layer on the third bonding material layer; and depositing a fourth bonding material layer on the second substrate, forming a second bonding surface with the second locking structure on the second substrate after stripping the second photoresist layer.

[0016] Further, the protrusion structure comprises an end portion away from the first bonding surface and a connecting portion connecting the end portion and the first bonding surface, the end portion has a width greater than the connecting portion in a direction along the first bonding surface; and the cavity structure comprises a first opening portion away from the second bonding surface and a second opening portion between the second bonding surface and the first opening portion, the first opening portion has a width less than the second opening portion in a direction along the second bonding surface.

[0017] Further, the end portion of the protrusion structure overflows outwardly and the first opening portion of the cavity structure overflows inwardly to form the interlocking structure when bonding.

[0018] Further, the width of the end portion is less than the width of the first opening portion.

[0019] Further, the end portion and the connecting portion form an inverted T-shaped structure, and the first opening portion and the second opening portion form a convex cavity structure.

[0020] Further, the first, second, third and fourth bonding material layers comprise at least one of Au, Al, Si, Ge, Ni, Cu and alloys thereof.

[0021] Further, the first bonding material layer has a thickness of 500nm-2000nm and a surface uniformity less than 5%, the second bonding material layer has a thickness of 500nm-2000nm and a surface uniformity less than 5%, the third bonding material layer has a thickness of 500nm-2000nm and a surface uniformity less than 5%, and the fourth bonding material layer has a thickness of 500nm-2000nm and a surface uniformity less than 5%.

[0022] Furthermore, before bonding the first substrate and the second substrate, the method further includes a step of cleaning the first bonding surface and the second bonding surface.

[0023] One aspect of this disclosure provides a chip including the bonding structure of this disclosure.

[0024] A semiconductor device is provided according to one aspect of this disclosure, including the chip of this disclosure.

[0025] The solution disclosed herein can help achieve at least one of the following effects: effectively withstand greater bonding pressure, reduce bonding pressure sensitivity, prevent bonding metal overflow, and improve bonding quality and strength. Attached Figure Description

[0026] The specific details of this disclosure are described below with reference to the accompanying drawings, which will facilitate a more readily understanding of the above and other objects, features, and advantages of this disclosure. The drawings are merely for illustrating the principles of this disclosure. The dimensions and relative positions of the elements are not necessarily drawn to scale in the drawings.

[0027] Figure 1 A schematic diagram of the bonding structure in the prior art is shown;

[0028] Figures 2-5 A schematic diagram according to the first embodiment is shown;

[0029] Figures 6a-6c A schematic diagram according to the second embodiment is shown. Detailed Implementation

[0030] Exemplary aspects of this disclosure will be described below with reference to the accompanying drawings. For clarity and brevity, not all features implementing this disclosure are described in the specification. However, it should be understood that many disclosure-specific decisions can be made in developing any such implementation of this disclosure to achieve the developer's specific goals, and these decisions may vary depending on the specific implementation of this disclosure.

[0031] It should also be noted that, in order to avoid obscuring the contents of this disclosure with unnecessary details, only the device structure closely related to the solution according to this disclosure is shown in the accompanying drawings, while other details that are not closely related to this disclosure are omitted.

[0032] It should be understood that this disclosure is not limited to the described embodiments by virtue of the following description with reference to the accompanying drawings. In this document, features may be substituted or borrowed between different embodiments where feasible, and one or more features may be omitted in one embodiment.

[0033] First Implementation Plan

[0034] See Figures 2-5 The same reference numerals in the figures denote the same elements. Figures 2-5 A first embodiment of the bonding structure of this disclosure is shown.

[0035] See Figure 2 The bonding structure includes a first device substrate 10a and a second device substrate 10b. A first bonding material layer 11a is formed on the first device substrate 10a, and a third bonding material layer 11b is formed on the second device substrate 10b. A first locking structure 12a, including a protruding structure, is formed on the surface of the first bonding material layer 11a. Specifically, the first locking structure can be a protruding inverted T-shaped structure. The first bonding material layer 11a and the first locking structure 12a constitute a first bonding layer. Corresponding to the first locking structure, a second locking structure 12b, including a cavity structure, is formed on the surface of the third bonding material layer 11b. The cavity structure corresponds to the protruding structure and is used to accommodate the protruding structure. Specifically, the second locking structure 12b can be a convex-shaped cavity structure. The third bonding material layer 11b and the second locking structure 12b constitute a second bonding layer.

[0036] See Figure 3 When bonding the first device substrate 10a and the second device substrate 10b, the protruding structure of the first locking structure and the cavity structure of the second locking structure are aligned. The width of the protruding part at the top of the inverted T-shaped protrusion is smaller than the width of the opening at the top of the convex cavity structure, so that the protruding structure is located inside the cavity structure. During heating and pressure bonding, the protruding part at the top of the protruding structure of the inverted T-shaped first locking structure 12a extends to both sides within the convex cavity structure of the second locking structure 12b. Simultaneously, the two ends of the upper opening of the convex cavity of the second locking structure 12b extend inwards after being compressed, so that the inverted T-shaped protrusion and the convex cavity structure form an interlocking structure. See [reference needed]. Figure 3 As shown by the middle arrow, the bonding material that overflows under pressure during bonding can form an interlocking structure through the bonding structure disclosed herein. Even if a large pressure is applied during bonding, the interlocking structure disclosed herein can form a left-right extrusion, which can improve the bonding quality and strength under the condition of withstanding a large bonding pressure.

[0037] It is understood that the first locking structure 12a of this disclosure is not limited to a protruding inverted T-shaped structure, and correspondingly, the second locking structure 12b is not limited to a convex cavity structure, as long as the bonding material overflowing under pressure during bonding can be squeezed horizontally by the two locking structures to form an interlocking structure. For example, see Appendix Figure 4 As shown, the first locking structure can be a protruding L-shape, and the second locking structure can be an inverted L-shape, forming an interlocking structure through the horizontal protrusions of the two L-shapes.

[0038] It is further understood that the bonding cross-sections of the first and second locking structures in the embodiments of this disclosure are both vertical cross-sections. See the appendix for details. Figure 5 As shown, it can also be set as an inclined profile. This can be formed due to etching processes or other reasons during the formation of the bonding structure, or it can be artificially made so that the first locking structure and the second locking structure can be more easily accommodated and aligned during bonding.

[0039] It is understood that the first and second bonding layers include at least one of Au, Al, Si, Ge, Ni, Cu, and their alloys. The thickness of the first or second bonding layer is 1000 nm to 4000 nm, and the surface uniformity is less than 5%.

[0040] Second Implementation Plan

[0041] See Figures 6a-6c The same reference numerals in the figures denote the same elements. Figures 6a-6c A second embodiment of the bonding method of this disclosure is shown.

[0042] Specifically, the bonding method disclosed herein has the following steps:

[0043] See Figure 6a A first bonding material layer 11a is deposited on the first substrate 10a. The thickness of the first bonding material layer 11a is 500 nm-2000 nm, and the surface uniformity is less than 5%. (See also...) Figure 6b After forming a first photoresist layer r1 on the first bonding material layer 11a, photolithography is performed. The thickness of the first photoresist layer r1 is 2 micrometers to 10 micrometers. The first photoresist layer r1 can be a negative photoresist or can use other similar techniques, such as lift-off techniques. The pattern formed by photolithography of the first photoresist layer r1 is used to form a first locking structure 12a including a protrusion structure after subsequent photoresist stripping; see also Figure 6c A second bonding material layer is deposited on a first substrate 10a. After the first photoresist layer is peeled off, a first bonding surface is formed on the first substrate 10a. The first bonding surface includes a first locking structure 12a with a protruding structure. The thickness of the second bonding material layer is 500nm-2000nm, and the surface uniformity is less than 5%. The damage to the first and second bonding material layers during the peeling off of the first photoresist layer is less than 100 angstroms, and no photoresist residue is ensured.

[0044] See further Figure 6a A third bonding material layer 11b is deposited on the second substrate 10b. The thickness of the third bonding material layer 11b is 500nm-2000nm, and the surface uniformity is less than 5%. (See also...) Figure 6bAfter forming a second photoresist layer r2 on the third bonding material layer 11b, photolithography is performed. The thickness of the second photoresist layer r2 is 2 micrometers to 10 micrometers. The second photoresist layer r2 can be a negative photoresist or can use other similar techniques, such as lift-off techniques. The pattern formed by photolithography of the second photoresist layer r2 is used to form a second locking structure 12b, including a cavity structure, after subsequent photoresist stripping. See also Figure 6c A fourth bonding material layer is deposited on the second substrate 10b. After the second photoresist layer is peeled off, a second bonding surface is formed on the second substrate 10b. The second bonding surface includes a second locking structure 12b with a cavity structure, which corresponds to the protrusion structure on the first substrate 10a and is used to accommodate the protrusion structure. The thickness of the fourth bonding material layer is 500nm-2000nm, and the surface uniformity is less than 5%. The damage to the third and fourth bonding material layers during the peeling off of the second photoresist layer is less than 100 angstroms, and no photoresist residue is ensured. Then, the surfaces of the first substrate and the second substrate are cleaned. Finally, the first substrate and the second substrate are bonded. Similar to the first embodiment, the first locking structure 12a and the second locking structure 12b interlock the overflowing bonding material during bonding.

[0045] It is understood that, similar to the first embodiment, the first locking structure 12a of this disclosure is not limited to a protruding inverted T-shaped structure, and correspondingly, the second locking structure 12b is not limited to a convex cavity structure, as long as the bonding material overflowing under pressure during bonding can form an interlocking structure by forming a horizontal compression through the two locking structures. For example, the first locking structure can be a protruding L-shaped structure, and the second locking structure can be an inverted L-shaped structure, with the interlocking structure formed by the horizontal protrusions of the two L-shaped structures.

[0046] The bonding structure disclosed herein can be used for chip manufacturing or packaging, and the chip disclosed herein can be used to manufacture semiconductor devices.

[0047] The foregoing description of this disclosure in conjunction with specific implementation schemes is exemplary and not intended to limit the scope of protection of this disclosure. Those skilled in the art can make various modifications and variations to this disclosure based on its spirit and principles, and such modifications and variations are also within the scope of this disclosure.

Claims

1. A bonding structure, comprising a first bonding layer and a second bonding layer, characterized in that: The first bonding layer includes a first bonding surface; The first bonding surface includes a first locking structure with a protruding structure; The second bonding layer includes a second bonding surface; The second bonding surface includes a second locking structure having a cavity structure, the cavity structure corresponding to the protrusion structure and used to accommodate the protrusion structure; as well as The first locking structure and the second locking structure form an interlocking structure when bonded; The protrusion structure includes an end away from the first bonding surface and a connecting portion connecting the end to the first bonding surface, wherein the end has a width greater than that of the connecting portion in the direction along the first bonding surface; as well as The cavity structure includes a first opening away from the second bonding surface and a second opening located between the second bonding surface and the first opening, wherein the first opening has a width smaller than that of the second opening in the direction along the second bonding surface.

2. The bonding structure as described in claim 1, wherein, During bonding, the end of the protruding structure overflows outward, and the first opening of the cavity structure overflows inward, forming the interlocking structure.

3. The bonding structure as described in claim 1, wherein, The width of the end is less than the width of the first opening.

4. The bonding structure as described in claim 1, wherein, The end portion and the connecting portion form an inverted T-shaped structure, and the first opening portion and the second opening portion form a convex cavity structure.

5. The bonding structure as described in claim 1, wherein, The first bonding layer and the second bonding layer include at least one of Au, Al, Si, Ge, Ni, Cu and their alloys.

6. The bonding structure as described in claim 1, wherein, The thickness of the first bonding layer or the second bonding layer is 1000nm-4000nm, and the surface uniformity is less than 5%.

7. A bonding method, the method comprising the following steps: A first bonding layer is formed on a first substrate, the first bonding layer including a first bonding surface, the first bonding surface including a first locking structure having a protrusion structure; A second bonding layer is formed on a second substrate. The second bonding layer includes a second bonding surface. The second bonding surface includes a second locking structure with a cavity structure, the cavity structure corresponding to the protrusion structure and used to accommodate the protrusion structure. as well as The first substrate and the second substrate are bonded together, and the first locking structure and the second locking structure form an interlocking structure during bonding; wherein, the protrusion structure includes an end away from the first bonding surface and a connection portion connecting the end and the first bonding surface, and the end has a width greater than the width of the connection portion in the direction along the first bonding surface; as well as The cavity structure includes a first opening away from the second bonding surface and a second opening located between the second bonding surface and the first opening, wherein the first opening has a width smaller than that of the second opening in the direction along the second bonding surface.

8. The bonding method as described in claim 7, wherein, The steps for forming the first bonding layer include: A first bonding material layer is deposited on a first substrate, and a first photoresist layer is formed on the first bonding material layer followed by photolithography; and A second bonding material layer is deposited on the first substrate, and after the first photoresist layer is stripped, a first bonding surface with the first locking structure is formed on the first substrate.

9. The bonding method as described in claim 8, wherein, The steps for forming the second bonding layer include: A third bonding material layer is deposited on a second substrate, and a second photoresist layer is formed on the third bonding layer followed by photolithography; and A fourth bonding material layer is deposited on the second substrate, and after the second photoresist layer is stripped, a second bonding surface with the second locking structure is formed on the second substrate.

10. The bonding method as described in claim 7, wherein, During bonding, the end of the protruding structure overflows outward, and the first opening of the cavity structure overflows inward, forming the interlocking structure.

11. The bonding method as described in claim 7, wherein, The width of the end is less than the width of the first opening.

12. The bonding method as described in claim 7, wherein, The end portion and the connecting portion form an inverted T-shaped structure, and the first opening portion and the second opening portion form a convex cavity structure.

13. The bonding method as described in claim 9, wherein, The first, second, third, and fourth bonding material layers include at least one of Au, Al, Si, Ge, Ni, Cu, and their alloys.

14. The bonding method as described in claim 9, wherein, The thickness of the deposited first bonding material layer is 500nm-2000nm, and the surface uniformity is less than 5%. The thickness of the deposited second bonding material layer is 500nm-2000nm, and the surface uniformity is less than 5%. as well as The thickness of the deposited third bonding material layer is 500nm-2000nm, and the surface uniformity is less than 5%. The thickness of the deposited fourth bonding material layer is 500nm-2000nm, and the surface uniformity is less than 5%.

15. The bonding method as described in claim 7, wherein, Before bonding the first substrate and the second substrate, the method further includes a step of cleaning the first bonding surface and the second bonding surface.

16. A chip comprising the bonding structure as described in any one of claims 1-6.

17. A semiconductor device comprising the chip of claim 16.

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