Package structure
By setting a buffer layer between the soft plate and the sub-packaging unit with a Young's modulus smaller than that of the sub-packaging unit, the layering problem of the packaging structure at the interface of soft and hard materials is solved, and a stable connection during the stretching and folding process is achieved.
Patent Information
- Application Number
- CN202422214012.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-10
- Publication Date
- 2025-08-22
- Estimated Expiration
- 2034-09-10
AI Technical Summary
The existing packaging structures are stratified by differences in material ductility at the interface between soft and hard materials, especially during repeated stretching and folding, which affects the stability and reliability of the packaging structure.
A buffer layer is used to fill the gap between the soft plate and the sub-packaging unit. The Young's modulus of the buffer layer is smaller than that of the sub-packaging unit. By gradually increasing the Young's modulus, the modulus difference of adjacent materials is reduced and the connection stability is enhanced.
It effectively avoids layering at the interface of soft and hard materials, improves the stability and reliability of the packaging structure during stretching and folding, and protects the fragile connection interface.
Smart Images
Figure CN223260586U_ABST
Abstract
Description
Technical Field
[0001] Embodiments of the present application relate to the field of semiconductor technology, and more particularly, to a packaging structure. Background Art
[0002] Wearable products have numerous applications, but this technology faces numerous challenges, such as material selection, suitable processes, and structural construction. For example, to achieve ergonomics, a flexible soft board is required as the base board. However, the flexibility of the soft board creates unresolved issues when placing electronic components on it.
[0003] Specifically, if Figure 1 As shown, in the initial state of the conventional package structure 10, the SIP (System in a Package) 14 is bonded to the flexible board 12. The connection interface 15s between the SIP 14 and the flexible board 12 is well bonded in a static state. The material of the SIP 14 is usually a hard material. The ductility and flexibility of the SIP 14 and the flexible board 12 are different. When the package structure 10 is stretched and folded, the materials of the SIP 14 and the flexible board 12 are bonded at the connection interface 15s ( Figure 1 ) is difficult to combine tightly. Figure 2A In the tensile state shown, the soft board 12 is stretched along the direction indicated by the arrow A1. After stretching, the SiP 14 moves from the initial position La to Figure 2A However, at this time, the SiP 14 cannot be extended together with the soft board 12, so after repeated stretching (as shown by arrow A3), delamination at the connection interface 15s may occur, so that the SiP 14 with high rigidity may fall off from the stretchable soft board 12. Figure 2B In the folded state shown, the soft board bends along the direction indicated by arrow A2, and the force can be divided into vertical and horizontal forces F1 and F2. Because SiP 14 cannot deform with soft board 12, delamination may occur at the fragile contact surface (i.e., the contact edge 16 between SIP 14 and soft board 12).
[0004] Traditional rigid packaging structures do not consider the effects of stretching, folding, or bending, and therefore do not account for the delamination issues caused by the significant differences in hardness and softness of the materials. Due to the new challenges of repeated stretching, traditional processes or structural designs may not be suitable for flexible packaging, which can directly lead to delamination at the interface between soft and hard materials. This has become a problem that needs to be solved. Utility Model Content
[0005] In response to the above problems, the present application proposes a packaging structure that can at least prevent delamination between the flexible circuit board and the components thereon.
[0006] According to one aspect of the present application, a packaging structure is provided, which includes: a flexible board including a base layer and a fixing layer arranged on the base layer; a sub-packaging unit arranged on the base layer, embedded in the fixing layer and exposed by the fixing layer; and a buffer layer arranged in a gap between the sub-packaging unit and the flexible board, wherein the Young's modulus of the buffer layer is smaller than the Young's modulus of the sub-packaging unit.
[0007] In some embodiments, the Young's modulus of the buffer layer is greater than the Young's modulus of the soft board.
[0008] In some embodiments, the sub-package unit is a detector.
[0009] In some embodiments, the package structure further includes: another sub-package unit electrically connected to the sub-package unit.
[0010] In some embodiments, the sub-package unit includes a chip and internal circuits.
[0011] In some embodiments, the base layer and the fixing layer of the flexible board are integrally formed.
[0012] In some embodiments, a top surface of the sub-package unit is at a first distance from a top surface of the flexible circuit board, and the first distance accounts for 0-70% of the thickness of the sub-package unit.
[0013] In some embodiments, the buffer layer is an adhesive layer for bonding the sub-package unit to the flexible board; the fixing layer surrounds the lower portion of the sub-package unit, and the buffer layer is filled between the lower portion of the sub-package unit and the fixing layer.
[0014] In some embodiments, the base layer includes a surface exposed by the fixing layer, a pad is disposed on the surface, and the sub-package unit is connected to the pad through a bump connector.
[0015] According to another aspect of the present application, a packaging structure is provided, comprising: a flexible circuit board comprising a plurality of stacked dielectric layers, wherein the uppermost dielectric layer of the plurality of dielectric layers defines a recess. The packaging structure further comprises: a sub-package unit disposed within the recess; and a buffer layer disposed within the recess and filling a gap between the sub-package unit and the flexible circuit board, wherein the buffer layer has a Young's modulus that is lower than that of the sub-package unit.
[0016] The beneficial effects of the above technical solution include:
[0017] In the above technical solution, by embedding the lower portion of the sub-package unit within the flexible circuit board, the entire sub-package unit is stabilized. Furthermore, a buffer layer with a smaller Young's modulus than the sub-package unit is used to fill the gap between the sub-package unit and the flexible circuit board, minimizing the difference in Young's modulus between the adjacent materials. This stabilizes and protects the sub-package unit and prevents delamination at the interface between the sub-package unit and the flexible circuit board. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0019] Figure 1 It is a cross-sectional schematic diagram of the existing packaging structure in the initial state.
[0020] Figure 2A yes Figure 1 Schematic diagram of the cross section of the soft board in the packaging structure under tension.
[0021] Figure 2B yes Figure 1 Schematic diagram of the cross section of the flexible board in the packaging structure in the folded state.
[0022] Figure 3A It is a cross-sectional schematic diagram of the packaging structure according to an embodiment of the present application.
[0023] Figure 3B is a schematic cross-sectional view of a packaging structure according to another embodiment of the present application.
[0024] Figures 4A to 4H 1 is a schematic cross-sectional view of multiple stages of forming a package structure according to an embodiment of the present application. DETAILED DESCRIPTION
[0025] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.
[0026] The following disclosure provides many different embodiments or examples for implementing the different features of the provided subject matter. Specific examples of components and arrangements will be described below to simplify the present invention. Of course, these are merely examples and are not intended to limit the present invention. For example, in the following description, forming a first component above or on a second component may include an embodiment in which the first component and the second component are in direct contact, and may also include an embodiment in which an additional component is formed between the first component and the second component so that the first component and the second component may not be in direct contact. Moreover, the present invention may repeatedly refer to numbers and / or letters in various examples. This repetition is merely for simplicity and clarity and does not in itself represent a relationship between the various embodiments and / or configurations discussed.
[0027] In addition, the embodiments and features of the embodiments of the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.
[0028] From the problems in the prior art, it can be seen that a packaging structure is needed to stably arrange components on a flexible board on the flexible board. Figure 3A FIG is a schematic cross-sectional view of a package structure 100 according to an embodiment of the present application. Figure 3A As shown, the package structure 100 may include a flexible board 120 and a sub-package unit 140A. The flexible board 120 may include a base layer 122 and a fixing layer 124 disposed on the base layer 122. The sub-package unit 140A is embedded in the fixing layer 124 and exposed by the fixing layer 124.
[0029] Package structure 100 may further include a buffer layer 170, which is disposed in the gap between the lower portion of sub-package unit 140A and flexible board 120. In some embodiments, the Young's modulus of buffer layer 170 is less than that of sub-package unit 140A. It should be understood that Young's modulus is a physical quantity that measures a solid material's ability to resist deformation and can be used to indicate the material's degree of hardness or softness. In some embodiments, buffer layer 170 is an adhesive layer, i.e., the material of buffer layer 170 is an adhesive, and buffer layer 170 can be used to bond sub-package unit 140A to flexible board 120.
[0030] In some embodiments, the flexible circuit board 120 includes a plurality of stacked dielectric layers, wherein the uppermost dielectric layer among the plurality of dielectric layers is a fixed layer 124, and the underlying dielectric layers (in this embodiment, two dielectric layers 1221 and 1222) serve as base layers 122. The fixed layer 124 defines a recess 1201 exposing the base layer 122, and the sub-package unit 140A is disposed on the base layer 122 within the recess 1201.
[0031] In package structure 100, by embedding the lower portion of sub-package unit 140A within flexible circuit board 120, the entire sub-package unit 140A is stabilized. Furthermore, a buffer layer 170, whose Young's modulus is lower than that of sub-package unit 140A, is used to fill the gap between sub-package unit 140A and flexible circuit board 120. This reduces the difference in Young's modulus between the adjacent materials, thereby stabilizing and protecting sub-package unit 140A and preventing delamination at the interface between sub-package unit 140A and flexible circuit board 120. This particularly strengthens the connection at the most vulnerable portion (the interface between sub-package unit 140A and flexible circuit board 120, where the difference in Young's modulus is greatest), preventing delamination at this location.
[0032] In some embodiments, the Young's modulus of buffer layer 170 is greater than that of flexible substrate 120, that is, the Young's modulus of buffer layer 170 is between that of flexible substrate 120 and that of sub-package unit 140A. This results in a gradual increase in the Young's modulus of flexible substrate 120, buffer layer 170, and sub-package unit 140A. Buffer layer 170 can provide a better buffering effect, protecting the lower portion of sub-package unit 140A surrounded by buffer layer 170 and preventing delamination at the interface between sub-package unit 140A and flexible substrate 120.
[0033] In some embodiments, the base layer 122 of the flexible circuit board 120 includes at least one dielectric layer (in this embodiment, two dielectric layers 1221 and 1222 are shown as an example), and the material of the fixed layer 124 can be the same as the material of the dielectric layer of the base layer 122. The base layer 122 may include a surface exposed by the fixed layer 124, and a pad 120P is provided on the surface exposed by the fixed layer 124. The sub-package unit 140A is connected to the pad 120P through a bump connector 149. The pad 120P can be connected to another conductive line 120L in the base layer 122 through a through hole 120V in the base layer 122. The bump connector 149 can be laterally surrounded by an underfill 146.
[0034] In some embodiments, the top surface of the buffer layer 170 may be higher than the top surface of the underfill 146. In this way, the buffer layer 170 filled between the fixing layer 124 and the sub-package unit 140A can cover the bottommost layer of the sub-package unit 140A (i.e., the underfill 146), thereby more effectively protecting the connection between the sub-package unit 140A and the flexible circuit board 120.
[0035] In some embodiments, the fixed layer 124 is a dielectric layer composed only of dielectric material. That is, no conductive components such as conductive lines or through holes are provided in the fixed layer 124 .
[0036] In some embodiments, the topmost dielectric layer 1222 and the fixed layer 124 in the base layer 122 may be integrally formed (ie, not separated into layers). Figure 3B FIG. 1 shows a schematic cross-sectional view of a packaging structure according to another embodiment of the present application. Figure 3B In the embodiment, the base layer 122 and the fixing layer 124 of the flexible circuit board 120 are integrally formed. Specifically, the dielectric layer 1222 at the top of the base layer 122 and the fixing layer 124 are integrally formed.
[0037] Return Reference Figure 3AAs shown, the top surface 140t of the sub-package unit 140A protrudes from the top surface 124t of the fixing layer 124 (i.e., the top surface of the flexible circuit board 120). In some embodiments, the top surface 140t of the sub-package unit 140A is a first distance D1 from the top surface of the flexible circuit board 120. The first distance D1 can account for 0-70% of the thickness of the sub-package unit 140A. When the ratio of the first distance D1 to the thickness of the sub-package unit 140A is the minimum value of 0 (i.e., D1=0), the top surface 140t of the sub-package unit 140A is flush with the top surface of the flexible circuit board 120. When the ratio of the first distance D1 to the thickness of the sub-package unit 140A is greater than 70%, the proportion of the sub-package unit 140A embedded in the fixing layer 124 is too small, and the function of fixing the sub-package unit 140A cannot be achieved.
[0038] Sub-package unit 140A may include chip 142A and a circuit layer 144A connected below chip 142A. Conductive components 144L are provided in circuit layer 144A, some of which may constitute internal circuitry within sub-package unit 140A. Bump connectors 149 are connected below circuit layer 144A. Circuit layer 144A may be used to electrically connect chip 142A to flexible circuit board 120.
[0039] Continue to refer Figure 3A As shown, package structure 100 may further include another sub-package unit 140B. Base layer 122 and fixing layer 124 of flexible circuit board 120 define another recess 1202 spaced apart from recess 1201. Package unit 140B is located in recess 1202. Sub-package unit 140B may be electrically connected to sub-package unit 140A via conductive traces 120L in base layer 122.
[0040] Sub-package unit 140B may have a similar structure to package unit 140A. Specifically, package unit 140B may include chip 142B and a circuit layer 144B connected to the bottom of chip 142B. Conductive components 144L are provided in circuit layer 144B, and some conductive components 144L may constitute internal circuits in sub-package unit 140B. Bump connectors 149 are connected to the bottom of circuit layer 144B and may be laterally surrounded by bottom filler 146. Sub-package unit 140B may be arranged similarly to sub-package unit 140A and will not be repeated here.
[0041] In some embodiments, at least one of the sub-package units 140A and 140B has a detection function, that is, at least one of the sub-package units 140A and 140B is a detector (also referred to as a sensor). In one example, sub-package unit 140A may be a SIP, and sub-package unit 140B may be a detector having a detection function. In such an embodiment, chip 142B of sub-package unit 140B may be a sensor chip having a detection function. A sensor chip is a device that requires energy or material exchange, such as an optical sensor chip, a chemical sensor chip, a thermal sensor chip, etc. In an embodiment in which sub-package unit 140B has a detection function, the detection end of chip 142B (sensor chip) of sub-package unit 140B may be exposed by fixing layer 124. This is because the detection end of the sensor chip that senses energy must be exposed in order to clearly sense the energy or material. The technical solution of the present application can expose the detection end of the chip 142B (sensor chip) for the sub-package unit 140B with a detection function, and can also stabilize and protect the sub-package unit 140B with a detection function, thereby avoiding delamination at the interface between the sub-package unit 140B and the flexible board 120.
[0042] The embodiments of the present application also provide a method for forming the above-mentioned packaging structure 100 . Figures 4A to 4H 1 is a schematic cross-sectional view at multiple stages of forming the package structure 100 according to an embodiment of the present application.
[0043] First reference Figure 4A As shown, a dielectric layer 1221 and a conductive line 120L located on the dielectric layer 1221 are provided. The conductive line 120L can be formed on the dielectric layer 1221 by a printing process.
[0044] refer to Figure 4B As shown, a cover dielectric layer 1222 is stacked on the dielectric layer 1221 and the conductive line 120L.
[0045] refer to Figure 4C As shown, a laser drilling process is performed on the dielectric layer 1222 to form an opening 401 in the dielectric layer 1222. The opening 401 exposes the conductive line 120L below the dielectric layer 1222.
[0046] refer to Figure 4D As shown, in Figure 4C The opening 401 is filled with a conductive material to form a through hole 120V. The conductive material may be a stretchable conductive paste. Thus, the base layer 122 is formed.
[0047] refer to Figure 4E As shown, a covering fixing layer 124 is stacked on the base layer 122 to form the flexible board 120. No conductive lines or through holes are formed in the fixing layer 124.
[0048] refer to Figure 4F As shown, recesses 1201 and 1202 are formed in the fixing layer 124, for example, by a laser process. Recesses 1201 and 1202 can expose the through-hole 120V in the base layer 122. In this embodiment, two recesses 1201 and 1202 are shown as an example, spaced apart from each other. In other embodiments, other numbers of recesses may be formed to allow for the subsequent arrangement of other sub-package units.
[0049] refer to Figure 4G As shown, two sub-package units 140A and 140B are placed in two recesses 1201 and 1202, respectively, and the two sub-package units 140A and 140B are respectively bonded to through-holes 120V in the base layer 122. Pads 120P can be provided above the through-holes 120V, and the sub-package units 140A and 140B are bonded to the pads 120P via bump connectors 149.
[0050] refer to Figure 4H As shown, a buffer layer 170 is filled between each sub-packaging unit 140A, 140B and the flexible board 120 to form a packaging structure 100 .
[0051] During the process of forming package structure 100, sub-package units 140A and 140B are first placed on flexible circuit board 120. Sub-package units 140A and 140B are partially embedded in flexible circuit board 120 for primary reinforcement. Then, a low-Young's modulus buffer layer 170, with a lower Young's modulus than sub-package units 140A and 140B, is used to fill the gap between sub-package units 140A and 140B and flexible circuit board 120 for secondary protection. By reducing the difference in Young's modulus, the risk of delamination is reduced, and the consistency of the overall package structure is improved.
[0052] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.
Claims
1. A packaging structure, characterized in that: include: A soft board comprises a base layer and a fixing layer provided on the base layer; a sub-packaging unit, disposed on the base layer, embedded in the fixing layer and exposed by the fixing layer; A buffer layer is provided in a gap between the sub-package unit and the flexible board, wherein the Young's modulus of the buffer layer is smaller than the Young's modulus of the sub-package unit.
2. The packaging structure according to claim 1, wherein: The Young's modulus of the buffer layer is also greater than the Young's modulus of the soft board.
3. The packaging structure according to claim 1, wherein: The sub-packaging unit is a detector.
4. The packaging structure according to claim 1, wherein: Also includes: Another sub-packaging unit is electrically connected to the sub-packaging unit.
5. The packaging structure according to claim 1, wherein: The sub-package unit includes a chip and an internal circuit.
6. The packaging structure according to claim 1, wherein: The base layer and the fixing layer of the soft board are formed in one piece.
7. The packaging structure according to claim 1, wherein: The top surface of the sub-packaging unit is at a first distance from the top surface of the flexible board, and the first distance accounts for 0-70% of the thickness of the sub-packaging unit.
8. The packaging structure according to claim 1, wherein: The buffer layer is an adhesive layer for bonding the sub-packaging unit and the flexible board; The fixing layer surrounds a lower portion of the sub-package unit, and the buffer layer is filled between the lower portion of the sub-package unit and the fixing layer.
9. The packaging structure according to claim 1, wherein: The base layer includes a surface exposed by the fixing layer, a pad is provided on the surface, and the sub-package unit is connected to the pad through a bump connector.
10. A packaging structure, characterized in that: include: A flexible board including a plurality of stacked dielectric layers, wherein an uppermost dielectric layer of the plurality of dielectric layers defines a recess; a sub-packaging unit, disposed in the recess; A buffer layer is disposed in the concave portion and fills a gap between the sub-package unit and the flexible board, wherein a Young's modulus of the buffer layer is smaller than a Young's modulus of the sub-package unit.