Manufacturing method of packaging structure

Abstract

The invention provides a manufacturing method of a packaging structure, and the method comprises the following steps: providing a to-be-packaged product which comprises a substrate layer and an air bridge disposed on the substrate layer; forming a first protective layer on the substrate layer, wherein the first protective layer surrounds the air bridge; patterning the first protection layer; removing a part of the first protection layer around the air bridge to form a notch, wherein one side, deviating from the substrate layer, of the notch is open; and forming a second protection layer on one side, deviating from the substrate layer, of the first protection layer, wherein the second protection layer covers the notch. According to the manufacturing method provided by the invention, the first protection layer is directly formed on the substrate layer, and the second protection layer covering the notch is formed on the first protection layer after the first protection layer is patterned to form the notch, so that the air bridge is effectively protected, and the manufacturing method is simple in process, low in manufacturing cost and high in yield. The original to-be-packaged product is not damaged, and the formed first protection layer and the second protection layer are stable in structure, so that the air bridge can be effectively protected.

Description

Technical Field

[0001] This invention relates to the field of chip manufacturing, and more particularly to a method for manufacturing a packaging structure. Background Technology

[0002] In some existing chips, air bridges need to be placed on their substrate. These air bridges have poor support, and due to chip structure requirements, their internal cavities cannot be filled with other materials for support. In existing technology, to protect the air bridge structure, a cap-shaped structure is pre-fabricated during chip packaging, and then the cap-shaped structure is pressed onto the chip to cover the air bridge. This method is complex, costly, and prone to damaging the chip, and is unsuitable for applications requiring wafer-level packaging. Summary of the Invention

[0003] The purpose of this invention is to provide a method for manufacturing a packaging structure that is simple in process, low in manufacturing cost, and avoids damage to the chip.

[0004] To achieve the above objectives, the present invention provides a method for manufacturing a packaging structure, comprising the following steps: A product to be packaged is provided, the product to be packaged including a substrate layer and an air bridge disposed on the substrate layer; A first protective layer is formed on the substrate layer, the first protective layer surrounding the air bridge; Patterning the first protective layer: Removing a portion of the first protective layer around the air bridge to form a slot, the slot being open on the side opposite to the substrate layer; A second protective layer is formed on the side of the first protective layer opposite to the substrate layer, and the second protective layer covers the slot.

[0005] As a further improvement of the present invention, the product to be packaged further includes a connection structure disposed on the substrate layer, and the first protective layer formed on the substrate layer surrounds the connection structure; The step of “patterning the first protective layer” further includes the following steps: removing a portion of the first protective layer to form a first window, the first window extending through the connection structure and the side of the first protective layer opposite to the substrate layer.

[0006] As a further improvement of the present invention, a second protective layer formed on the side of the first protective layer opposite to the substrate layer covers the first window; The manufacturing method further includes the following steps: Patterning the second protective layer: Removing a portion of the second protective layer to form a second window, the position of which corresponds to the position of the first window.

[0007] As a further improvement of the present invention, the connection structure is a rewiring layer, and the manufacturing method further includes the following steps: A bump is formed on the redistribution layer, the bump being located within the first opening.

[0008] As a further improvement of the present invention, the first protective layer is made of a negative photosensitive material, and the step of "patterning the first protective layer" includes the following steps: A mask is used to cover part of the first protective layer. The area of ​​the first protective layer covered by the mask is the first non-exposed area, and the area not covered by the mask is the first exposed area. The position of the slot and the first window coincides with the position of the first non-exposed area. The first protective layer is exposed to cause denaturation in the first exposed area; The first unexposed area is dissolved using a developer to form the groove and the first window.

[0009] As a further improvement of the present invention, the step of "forming a second protective layer on the side of the first protective layer away from the substrate layer, the second protective layer covering the slot" includes the following steps: Provides a solid-state second protective layer; The solid second protective layer is adhered to the side of the first protective layer away from the substrate layer, and the second protective layer covers the slot.

[0010] As a further improvement of the present invention, the material of the second protective layer is a negative photosensitive material, and the step of "patterning the second protective layer" includes the following steps: A mask is used to cover part of the second protective layer. The area of ​​the second protective layer covered by the mask is the second non-exposed area, and the area not covered by the mask is the second exposed area. The position of the second window coincides with the position of the second non-exposed area. The second protective layer is exposed to cause denaturation in the second exposed area; The second unexposed area is dissolved using a developer to form the second window.

[0011] As a further improvement of the present invention, both the first protective layer and the second protective layer are made of polyimide.

[0012] As a further improvement of the present invention, the length and width of the slot are both no greater than 80 micrometers.

[0013] As a further improvement of the present invention, the packaging structure is a wafer-level packaging structure, and the product to be packaged includes a plurality of chip units, wherein the chip units are provided with the air bridge.

[0014] Beneficial effects: The manufacturing method of the packaging structure provided by this invention directly forms a first protective layer on a substrate layer. After patterning the first protective layer to form a slot, a second protective layer is then formed on the first protective layer to cover the slot, effectively protecting the air bridge. Therefore, the air bridge structure will not be damaged during subsequent packaging of the product to be packaged. Compared with existing technologies, the above manufacturing method has a simple process, low manufacturing cost, does not damage the original product to be packaged, and the formed first and second protective layers are structurally stable, effectively protecting the air bridge. Attached Figure Description

[0015] Figure 1 A flowchart illustrating a method for manufacturing a packaging structure according to an embodiment of the present invention; Figure 2-9 This is a schematic diagram illustrating the steps of a method for manufacturing a packaging structure according to an embodiment of the present invention; Figure 10 A top view of the product to be packaged in a method for manufacturing a packaging structure according to an embodiment of the present invention.

[0016] In the picture: 10. Product to be packaged; 11. Substrate layer; 12. Air bridge; 121. Cavity; 13. Chip unit; 20. First protective layer; 21. Groove; 22. First window; 23. First non-exposure area; 24. First exposure area; 30. Second protective layer; 31. Second window; 32. Second non-exposure area; 33. Second exposure area; 40. Connection structure; 41. Rerouting layer; 50. Bumps. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any modifications to the mechanism, method, or function made by those skilled in the art based on these embodiments are included within the scope of protection of the present invention.

[0018] The terms used herein, such as "up," "down," "left," "right," "front," and "back," indicating spatial relative position, are for illustrative purposes to describe the relationship of one feature relative to another, as shown in the accompanying drawings. It is understood that, depending on the product's placement, these terms may be intended to include different orientations besides those shown in the figures, and should not be construed as limiting the claims. Furthermore, the descriptive term "horizontal" used herein is not entirely equivalent to being perpendicular to the direction of gravity, and allows for a certain angle of inclination.

[0019] like Figure 1-9 As shown, an embodiment of the present invention provides a method for manufacturing a packaging structure, the method comprising the following steps: like Figure 2 As shown, a product to be packaged 10 is provided, which includes a substrate layer 11 and an air bridge 12 disposed on the substrate layer 11.

[0020] The product to be packaged 10 can be prefabricated, and the substrate layer 11 can be made of materials such as gallium arsenide and silicon as needed. The air bridge 12 is a bridge-shaped structure with an internal cavity 121, which can be made of metal materials such as aluminum and copper. The cavity 121 of the air bridge 12 has a specific function in the chip, such as allowing other structures to pass through and reducing parasitic capacitance.

[0021] like Figure 3 As shown, a first protective layer 20 is formed on the substrate 11, and the first protective layer 20 surrounds the air bridge 12.

[0022] When the first protective layer 20 surrounds the air bridge 12, the first protective layer 20 is disposed around the air bridge 12 and can be attached to the outer periphery of the air bridge 12. The first protective layer 20 is higher than the air bridge 12 so as to cover the top of the air bridge 12. For example, the height of the air bridge 12 can be 7.5 micrometers, and the height of the first protective layer 20 can be 10 to 15 micrometers.

[0023] like Figure 4-5 As shown, a first protective layer 20 is patterned. Patterning the first protective layer 20 specifically includes the following steps: removing a portion of the first protective layer 20 around the air bridge 12 to form a slot 21, within which the air bridge 12 is located. The slot 21 is open on the side facing away from the substrate layer 11.

[0024] like Figure 6 As shown, a second protective layer 30 is formed on the side of the first protective layer 20 away from the substrate layer 11, and the second protective layer 30 covers the slot 21.

[0025] After the above steps are performed, the air bridge 12 is located in the slot 21, and the side of the slot 21 facing away from the substrate layer 11 is closed by the second protective layer 30. The first protective layer 20 and the second protective layer 30 can protect the air bridge 12.

[0026] The manufacturing method of the packaging structure provided in this embodiment directly forms a first protective layer 20 on the substrate layer 11. After patterning the first protective layer 20 to form a slot 21, a second protective layer 30 is then formed on the first protective layer 20 to cover the slot 21, effectively protecting the air bridge 12. Therefore, when the product 10 to be packaged is subsequently packaged, the air bridge 12 structure will not be damaged. Compared with the prior art, the above manufacturing method has a simple process, low manufacturing cost, and will not damage the original product 10 to be packaged. Furthermore, the formed first protective layer 20 and second protective layer 30 have stable structures and can effectively protect the air bridge 12.

[0027] like Figure 3-5 As shown, in this embodiment, the product to be packaged 10 further includes a connection structure 40 disposed on the substrate layer 11. A first protective layer 20 formed on the substrate layer 11 surrounds the connection structure 40; that is, when the first protective layer 20 is formed, it is disposed around the connection structure 40 and can be attached to the outer periphery of the connection structure 40. The first protective layer 20 is higher than the connection structure 40 so as to cover the top of the connection structure 40.

[0028] The above-mentioned step "patterning the first protective layer 20" also includes the following steps: removing a portion of the first protective layer 20 to form a first window 22, wherein the first window 22 extends through the connecting structure 40 and the side of the first protective layer 20 facing away from the substrate layer 11.

[0029] The connecting structure 40 is a structure that needs to connect with other structures. After the first window 22 is formed on the first protective layer 20, during the subsequent encapsulation process of the product 10 to be packaged, other structures that need to connect with the connecting structure 40 extend into the first window 22 and can connect with the connecting structure 40. Both the slot 21 and the first window 22 are formed after removing part of the material from the first protective layer 20. Both can be made simultaneously using the same process, thus reducing process steps and improving production efficiency.

[0030] like Figure 6 As shown, in this embodiment, the second protective layer 30 formed on the side of the first protective layer 20 away from the substrate layer 11 covers the first opening 22, that is, when the second protective layer 30 is formed, it covers the first opening 22.

[0031] like Figure 7-8 As shown, the manufacturing method of the packaging structure also includes the following steps: The second protective layer 30 is patterned. Patterning the second protective layer 30 specifically includes the following steps: removing a portion of the second protective layer 30 to form a second window 31, the position of which corresponds to the first window 22. After the second window 31 is formed, the first window 22 can communicate with the outside world through the second window 31.

[0032] In the above steps, the second protective layer 30 covers the first opening 22 during its formation, and then a portion of the material of the second protective layer 30 is removed to form the second opening 31 corresponding to the first opening 22. During the subsequent encapsulation process of the product 10 to be packaged, other structures that need to be connected to the connecting structure 40 can enter the first opening 22 through the second opening 31.

[0033] The above-mentioned method of first forming a second protective layer 30 covering the first window 22, and then removing part of the second protective layer 30 to form the second window 31, makes it possible to form the second protective layer 30 without controlling the formation area of ​​the second protective layer 30. When forming the second protective layer 30, there is no need to consider the position of the first window 22, and it can directly cover the entire first protective layer 20, making the second protective layer 30 easier to form in terms of process.

[0034] In this embodiment, the connection structure 40 is a rewiring structure. For example... Figure 9 As shown, the manufacturing method of the packaging structure also includes the following steps: A bump 50 is made on the redistribution layer 41, and the bump 50 is located inside the first window 22.

[0035] In subsequent packaging processes, bump 50 can serve as an interconnect unit, enabling redistribution layer 41 to achieve electrical connections with other structures. Compared to traditional wire bonding packaging, the placement of bump 50 can shorten the signal transmission path of the chip, reduce parasitic inductance and capacitance, and reduce signal delay and crosstalk.

[0036] It is conceivable that in other embodiments of the present invention, the connection structure 40 may be other structures besides the redistribution layer 41, which are not limited here.

[0037] In this embodiment, the first protective layer 20 is made of a negative photosensitive material. When exposed to light, the negative photosensitive material undergoes internal denaturation, and the unexposed areas can be dissolved and removed by a developing solution.

[0038] like Figure 4-5 As shown, the above step "patterning the first protective layer 20" specifically includes the following steps: A mask is used to partially cover the first protective layer 20. The first protective layer 20 has a first non-exposed area 23 and a first exposed area 24. The area of ​​the first protective layer 20 covered by the mask is the first non-exposed area 23, and the area of ​​the first protective layer 20 not covered by the mask is the first exposed area 24. The positions of the notch 21 and the first window 22 coincide with the position of the first non-exposed area 23. The first protective layer 20 is exposed to cause the first exposed area 24 to undergo denaturation. The first unexposed area 23 is dissolved using a developer to form a groove 21 and a first window 22.

[0039] When using the developer to dissolve the first non-exposed area 23, a spin coating development process can be used. By rotating the developer at high speed, the development rate and the edge morphology of the groove 21 and the first window 22 can be precisely controlled.

[0040] In the above steps, a mask is used to cover the first non-exposed area 23 corresponding to the positions of the slot 21 and the first window 22. This ensures that when the first protective layer 20 is subsequently exposed, only the first exposed area 24, which is not covered by the mask, will undergo denaturation. After denaturation, the first exposed area 24 is less soluble in the developing solution. Therefore, the developing solution will only dissolve the first non-exposed area 23, resulting in the removal of only the material corresponding to the positions of the slot 21 and the first window 22 from the first protective layer 20. By employing these steps, high-precision patterning of the first protective layer 20 can be achieved, ensuring that the formed slot 21 and the first window 22 are accurately positioned and have clear boundaries.

[0041] Regarding the statement that "the positions of the slot 21 and the first window 22 coincide with the position of the first non-exposure area 23", it should be noted that the second protective layer 30 has two first non-exposure areas 23. One of the two first non-exposure areas 23 corresponds to the position of the slot 21, and the other corresponds to the position of the first window 22.

[0042] After dissolving the first non-exposed area 23 with a developer, the manufacturing method of the packaging structure may further include the following steps: Bake the first protective layer 20 to cure it; Plasma cleaning slot 21 and first opening 22.

[0043] In the above steps, baking the first protective layer 20 can further solidify the remaining first exposure area 24 of the first protective layer 20, thereby ensuring the structural strength of the first protective layer 20. Using plasma to clean the slot 21 and the first opening 22 can further remove material from the first protective layer 20 in order to precisely shape the slot 21 and the first opening 22.

[0044] In other embodiments of the present invention, the first protective layer 20 may be made of a positive photosensitive material. The exposed areas of the positive photosensitive material can be removed using a developing solution. In this case, the positions of the slot 21 and the first window 22 should coincide with the first exposure area 24.

[0045] The above step of "forming a second protective layer 30 on the side of the first protective layer 20 away from the substrate layer 11, the second protective layer 30 covering the slot 21" includes the following steps: Provides a solid-state second protective layer 30; The solid second protective layer 30 is attached to the side of the first protective layer 20 away from the substrate layer 11, and the second protective layer 30 covers the slot 21.

[0046] In the above steps, the solid second protective layer 30 is the already formed second protective layer 30, and the second protective layer 30 will not flow in a liquid state. The second protective layer 30 can be first wrapped around the roller, and then rolled on the first protective layer 20 to make the second protective layer 30 adhere to the first protective layer 20.

[0047] Compared to the method of first applying a liquid second protective layer 30 and then curing the liquid second protective layer 30, the above steps use a solid second protective layer 30 to adhere to the second protective layer 30, which can prevent the second protective layer 30 from flowing into the groove 21 and the second window 31, and can ensure the flatness of the second protective layer 30.

[0048] In this embodiment, the second protective layer 30 is made of a negative photosensitive material. For example... Figure 7-8 As shown, the above step "patterning the second protective layer 30" specifically includes the following steps: A mask is used to partially cover the second protective layer 30. The second protective layer 30 has a second non-exposed area 32 and a second exposed area 33. The area of ​​the second protective layer 30 covered by the mask is the second non-exposed area 32, and the area of ​​the second protective layer 30 not covered by the mask is the second exposed area 33. The position of the second window 31 coincides with the position of the second non-exposed area 32. The second protective layer 30 is exposed to cause the second exposure area 33 to undergo denaturation. The second unexposed area 32 is dissolved using a developer to form the second window 31.

[0049] When using the developer to dissolve the first non-exposed area 23, a spin coating development process can be used. By rotating the developer at high speed, the development rate and the edge morphology of the groove 21 and the first window 22 can be precisely controlled.

[0050] In the above steps, a mask is used to cover the second non-exposed area 32 corresponding to the position of the second window 31. This ensures that when the second protective layer 30 is subsequently exposed, only the second exposed area 33, which is not covered by the mask, will undergo denaturation. After denaturation, the second exposed area 33 is less soluble in the developing solution. Therefore, the developing solution will only dissolve the second non-exposed area 32, resulting in the removal of only the material corresponding to the position of the second window 31 from the second protective layer 30. By employing these steps, high-precision patterning of the second protective layer 30 can be achieved, ensuring that the formed second window 31 is accurately positioned and has clear boundaries.

[0051] In this embodiment, both the first protective layer 20 and the second protective layer 30 are made of polyimide (PI). Polyimide has excellent heat resistance, chemical stability and mechanical strength, and can effectively protect the air bridge 12 in subsequent packaging processes.

[0052] In this embodiment, after dissolving the second non-exposed area 32 with the developer, the manufacturing method of the packaging structure may further include the following steps: Plasma cleaning second window 31; Bake the second protective layer 30 to cure the first protective layer 20.

[0053] In the above steps, plasma cleaning of the second window 31 can further remove material from the second protective layer 30 to precisely shape the second window 31. Baking the second protective layer 30 can further solidify the remaining second exposure area 33 of the second protective layer 30, thereby ensuring the structural strength of the second protective layer 30.

[0054] Solid polyimide in the form of a "dry film" is difficult to remove after baking. Therefore, cleaning the second window 31 with plasma before baking in the above steps is easy to implement in terms of process.

[0055] It is conceivable that, in other embodiments of the present invention, the material of the second protective layer 30 may be a positive photosensitive material. In this case, the position of the second window 31 should coincide with the second exposure area 33.

[0056] Generally, photosensitive materials are not sensitive to yellow light. The manufacturing method of the encapsulation structure in this embodiment can be carried out under yellow light.

[0057] In this embodiment, the length and width of the slot 21 are both no greater than 80 micrometers. Thus, the second protective layer 30 will not collapse at the slot 21 when subjected to pressure. The thickness of the second protective layer 30 is 35 to 40 micrometers to provide sufficient strength.

[0058] like Figure 1 , 10 As shown, in this embodiment, the packaging structure is a wafer-level packaging structure. The product to be packaged 10 includes several chip units 13, and air bridges 12 are provided on the chip units 13. Wafer-level packaging means that the several chip units 13 of the product to be packaged 10 are packaged at the wafer level. After the first protective layer 20 and the second protective layer 30 are formed, the first protective layer 20 and the second protective layer 30 can protect the air bridges 12 on the multiple chip units 13. With the first protective layer 20 and the second protective layer 30 effectively protecting the air bridges 12, there is no need to worry about the air bridges 12 being affected by chemical corrosion, water flow impact, etc. during the packaging process during subsequent wafer-level packaging.

[0059] When forming the first protective layer 20 on the substrate, a liquid first protective layer 20 material can be first coated onto the substrate 11, and then the liquid first protective layer 20 material can be cured. In this way, the first protective layer 20 can be reliably bonded to the substrate 11. When forming the first protective layer 20, the first protective layer 20 basically covers the entire substrate 11. Therefore, the first protective layer 20 can protect the other structures on the substrate 11 except for the air bridge 12.

[0060] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0061] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application.

Claims

1. A method for manufacturing a packaging structure, characterized in that, Includes the following steps: A product to be packaged is provided, the product to be packaged including a substrate layer and an air bridge disposed on the substrate layer; A first protective layer is formed on the substrate layer, the first protective layer surrounding the air bridge; Patterning the first protective layer: Removing a portion of the first protective layer around the air bridge to form a slot, the slot being open on the side opposite to the substrate layer; A second protective layer is formed on the side of the first protective layer away from the substrate layer, and the second protective layer covers the slot.

2. The manufacturing method according to claim 1, characterized in that, The product to be packaged also includes a connection structure disposed on the substrate layer, and the first protective layer formed on the substrate layer surrounds the connection structure. The step "patterning the first protective layer" further includes the following steps: removing a portion of the first protective layer to form a first window, the first window extending through the connection structure and the side of the first protective layer opposite to the substrate layer.

3. The manufacturing method according to claim 2, characterized in that, A second protective layer, formed on the side of the first protective layer opposite to the substrate layer, covers the first opening. The manufacturing method further includes the following steps: Patterning the second protective layer: Removing a portion of the second protective layer to form a second window, the position of which corresponds to the position of the first window.

4. The manufacturing method according to claim 3, characterized in that, The connection structure is a rewiring layer, and the manufacturing method further includes the following steps: A bump is formed on the redistribution layer, the bump being located within the first opening.

5. The manufacturing method according to claim 2, characterized in that, The first protective layer is made of a negative photosensitive material, and the step of "patterning the first protective layer" includes the following steps: A mask is used to cover part of the first protective layer. The area of ​​the first protective layer covered by the mask is the first non-exposed area, and the area not covered by the mask is the first exposed area. The position of the slot and the first window coincides with the position of the first non-exposed area. The first protective layer is exposed to cause denaturation in the first exposed area; The first unexposed area is dissolved using a developer to form the groove and the first window.

6. The manufacturing method according to claim 3, characterized in that, The step of "forming a second protective layer on the side of the first protective layer away from the substrate layer, the second protective layer covering the slot" includes the following steps: Provides a solid-state second protective layer; The solid second protective layer is adhered to the side of the first protective layer away from the substrate layer, and the second protective layer covers the slot.

7. The manufacturing method according to claim 6, characterized in that, The second protective layer is made of a negative photosensitive material, and the step of "patterning the second protective layer" includes the following steps: A mask is used to cover part of the second protective layer. The area of ​​the second protective layer covered by the mask is the second non-exposed area, and the area not covered by the mask is the second exposed area. The position of the second window coincides with the position of the second non-exposed area. The second protective layer is exposed to cause denaturation in the second exposed area; The second unexposed area is dissolved using a developer to form the second window.

8. The manufacturing method according to any one of claims 1-7, characterized in that, Both the first protective layer and the second protective layer are made of polyimide.

9. The manufacturing method according to any one of claims 1-7, characterized in that, The length and width of the slot are both no more than 80 micrometers.

10. The manufacturing method according to any one of claims 1-7, characterized in that, The packaging structure is a wafer-level packaging structure, and the product to be packaged includes several chip units, with the air bridge provided on the chip units.

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