An isostatic pressing encapsulation method for LTCC ceramic substrates
By designing encapsulation methods using metal pads and enclosure structures with different side lengths, the problems of uneven shrinkage and unstable encapsulation of large-size ceramic substrates were solved, achieving high-precision shrinkage rate control and simple automated production, which is suitable for LTCC ceramic substrates.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- MAXONE SEMICON CO LTD
- Filing Date
- 2026-01-20
- Publication Date
- 2026-05-26
AI Technical Summary
In existing technologies, single-sided encapsulation is prone to uneven shrinkage during the fabrication of large-size ceramic substrates, while double-sided encapsulation of the same size has problems such as encapsulation instability and easy breakage due to corner risks, making it difficult to adapt to large-scale automated production.
Two square metal pads with different side lengths are used, designed as a large pad and a small pad. Combined with the enclosure structure, PET film and silicone pad, a closed containment space is formed. The encapsulation is carried out through vacuum encapsulation and isostatic pressing process to ensure uniform stress and shrinkage control of the laminate.
It achieves high-precision shrinkage control, avoids encapsulation damage, simplifies the operation process, reduces costs, is suitable for large-scale automated production, and is applicable to LTCC ceramic substrates with sizes of 380~480mm and larger.
Smart Images
Figure CN122078038A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of low-temperature co-fired ceramic (LTCC) substrate manufacturing technology, and in particular to an isostatic pressing encapsulation method suitable for LTCC ceramic substrates. Background Technology
[0002] Low-temperature co-fired ceramics (LTCC), as a novel multilayer circuit board manufacturing technology, has broad application prospects in communications, semiconductors, and other fields. In the forming process of processing single-layer green ceramic sheets into multilayer green ceramic blanks, isostatic pressing is a crucial step for bonding the green ceramic and controlling the shrinkage rate. Because this process requires placing the laminated body in a high-temperature, high-pressure liquid environment, the encapsulation method before this process has high requirements in terms of strength, toughness, and ease of operation.
[0003] Currently, common isostatic pressing (OSP) encapsulation methods mainly include single-sided encapsulation and equal-size double-sided encapsulation, representing encapsulation using one OSP pad and encapsulation using two equal-size OSP pads, respectively. Single-sided encapsulation, using only one OSP pad, offers advantages such as low cost, ease of operation, low breakage rate, and high stability. However, when applied to the fabrication of large-size ceramic substrates, it is prone to uneven shrinkage and other defects, making it difficult to meet standards. Therefore, it is mostly suitable for isostatic pressing processes on small-size ceramic substrates. Equal-size double-sided encapsulation performs well in controlling the shrinkage rate of ceramic substrates of various sizes. However, it also has risks such as sharp edges and corners leading to unstable encapsulation effects and susceptibility to breakage and leakage, resulting in product scrap. These drawbacks significantly affect the practical application of equal-size double-sided encapsulation. Furthermore, most encapsulation improvements based on these two methods are cumbersome to operate and difficult to adapt to large-scale automated production.
[0004] Therefore, how to provide an isostatic encapsulation method that is easy to operate, low in cost, has good shrinkage control, and is suitable for large-scale production is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention
[0005] This invention provides an isostatic pressing encapsulation method suitable for LTCC ceramic substrates to solve the above-mentioned technical problems.
[0006] To address the aforementioned technical problems, this invention provides an isostatic pressing encapsulation method suitable for LTCC ceramic substrates, comprising the following steps:
[0007] Step 1: Design two square metal pads with different side lengths, named the large pad and the small pad respectively; the four edges of the large pad and the small pad are respectively provided with a barrier structure perpendicular to the plate surface to form a square cover structure;
[0008] Step 2: Obtain the laminate, one side of which is a micro-adhesive film surface and the other side is a non-film surface. Place the micro-adhesive film surface downwards inside the large board pad with the enclosure structure facing upwards.
[0009] Step 3: Place an equally sized PET film on the unfilmed side of the laminate for lamination;
[0010] Step 4: Place the small board pad with the fencing structure facing down on the PET film, clamp the laminate and fix it;
[0011] Step 5: Cover and secure the overall structure formed in Step 4 with a silicone pad;
[0012] Step 6: Place the overall structure formed in Step 5 into a vacuum-sealed bag and seal it.
[0013] Step 7: After inspection, proceed with the isostatic pressing process.
[0014] Preferably, the thickness of the large plate and the small plate is 3~8mm, and the difference in their side lengths is 5~20mm.
[0015] Preferably, the side length of the large plate pad is 400mm, and the side length of the small plate pad is 390mm.
[0016] Preferably, the height of the enclosure structure is 4-10mm, and the thickness is the same as that of the corresponding pad.
[0017] Preferably, the enclosure structure and the corresponding pad are integrally formed.
[0018] Preferably, the corners of the large plate pad and the small plate pad are rounded by 1-3mm, and the edges are rounded by 0.3-1mm.
[0019] Preferably, the laminate is a 380mm green ceramic laminate, the size of the micro-adhesive surface matches the size of the large plate pad, the green ceramic laminate is placed in the center inside the large plate pad, and the four corners of the micro-adhesive surface are fixed with tape.
[0020] Preferably, in step 4, the small plate pad is placed centered on the PET film, and the relative positions of the small plate pad and the large plate pad are fixed by tape.
[0021] Preferably, the silicone pad is square with a side length of 800~900mm, and the silicone pad is fixed in a covered state by tape.
[0022] Preferably, in step 7, the inspection includes: confirming that the packaging bag and its internal structure are free of foreign objects, hard parts, structural damage, and there is no risk of leakage.
[0023] Compared with the prior art, the isostatic pressing encapsulation method for LTCC ceramic substrates provided by the present invention has the following advantages:
[0024] 1. This invention utilizes two square cap structures of different sizes to completely encapsulate the laminated body, eliminating encapsulation damage caused by internal factors. Moreover, in terms of shrinkage control, there is almost no significant difference compared to the encapsulation of equal-sized double-sided panels, and the accuracy can be controlled within 0.03%. This invention addresses the pain points of existing single-sided and double-sided panel encapsulation from the root cause.
[0025] 2. This invention adopts a seven-step standardized process with no complicated new operations, making it relatively simple to operate. This results in a low learning cost for the packaging method and moderate time consumption, which helps to improve production efficiency. The auxiliary materials and equipment are all conventional types with low cost and can be directly connected to automated production lines to further improve production efficiency.
[0026] 3. This invention does not require modification of existing equipment, can be flexibly adapted to substrates of 380~480mm and larger, has strong compatibility, is easy to promote in the industry, and provides reliable process support for the communications and semiconductor fields. Attached Figure Description
[0027] Figure 1 This is a schematic diagram of an isostatic pressing encapsulation method for LTCC ceramic substrates according to a specific embodiment of the present invention.
[0028] In the diagram: 10-Large plate pad, 11-Enclosure structure, 20-Layered body, 21-Micro adhesive film surface, 30-PET film, 40-Small plate pad, 50-Silicone pad. Detailed Implementation
[0029] To illustrate the technical solutions of the invention in more detail, specific embodiments are listed below to demonstrate the technical effects; it should be emphasized that these embodiments are used to illustrate the invention and not to limit the scope of the invention.
[0030] The isostatic pressing encapsulation method for LTCC ceramic substrates provided by this invention, such as... Figure 1 As shown, it includes the following steps:
[0031] Step 1: Design two square metal pads with different side lengths, named large pad 10 and small pad 40 respectively. Each of the four edges of large pad 10 and small pad 40 has a perpendicular enclosure structure 11, forming a square cover structure. The square cover structure forms a closed containment space through the enclosure structure 11, preventing the laminate 20 from shifting or misaligning during subsequent operations and isostatic pressing. It also isolates the internal laminate 20 from the external encapsulation structure, preventing damage to the encapsulation caused by the sharp edges of the membrane or green ceramic itself. The size difference between the large and small plates not only provides reasonable placement space for the laminate 20 but also ensures uniform force on the laminate 20 through clamping force, laying the foundation for precise control of the shrinkage rate in the future.
[0032] Step 2: Obtain the laminate 20. One side of the laminate 20 is the micro-adhesive membrane surface 21, and the other side is the membrane-free surface. Place the laminate 20 with the micro-adhesive membrane surface 21 facing down inside the large plate pad 10 of the enclosure structure 11 facing upwards. The initial fixing effect of the micro-adhesive membrane surface 21 reduces the risk of displacement of the laminate 20 during subsequent operations such as lamination and placement of the small plate pad 40.
[0033] Step 3: Place an equally sized PET film 30 on the unfilmed side of the laminate 20 for lamination. The PET film 30 serves as an isolation and protection mechanism, preventing scratch damage caused by direct contact between the small plate pad 40 and the laminate 20. It also prevents the laminate 20 and the pad from sticking together after isostatic pressing and becoming inseparable.
[0034] Step 4: Place the small board pad 40 with the fencing structure facing down on the clean PET film 30, clamp and fix the laminate 20 to prevent the pad from loosening during isostatic pressing.
[0035] Step 5: Cover and secure the overall structure formed in Step 4 with the silicone pad 50. The high elasticity of the silicone pad 50 can buffer the impact of liquid during isostatic pressing and prevent the edges of the pad from scratching the vacuum-sealed bag. The fully covered design further enhances the sealing performance, preventing high-pressure liquid from seeping into the encapsulation. At the same time, the flexible contact of the silicone pad 50 can protect the pad and PET film 30, reducing the risk of breakage.
[0036] Step 6: Center the overall structure formed in Step 5 into a 600mm nylon vacuum-sealing bag, and then place it into a vacuum sealing machine for sealing. The high-vacuum sealing environment can expel the air inside the package, avoiding uneven pressure caused by the thermal expansion of air during isostatic pressure, which would affect the shrinkage effect of the laminate 20.
[0037] Step 7: Remove the sealed bag, inspect it, and then proceed with the isostatic pressing process. A rigorous inspection process can eliminate sealing defects in advance, preventing substandard bags from entering the isostatic pressing process and causing product scrap, thus improving the production pass rate.
[0038] In some embodiments, the thickness of the large plate pad 10 and the small plate pad 40 is 3-8 mm, and the difference in their side lengths is 5-20 mm. This adaptable thickness design ensures the supporting strength of the pads while avoiding increased costs and operational inconvenience caused by excessive thickness. The reasonable difference in side lengths ensures that the layers of material adhere tightly during the encapsulation process without excess gaps, thereby guaranteeing accurate shrinkage control. It also allows compatibility with laminates 20 of different sizes, improving the versatility of the method. In this embodiment, the side length of the large plate pad 10 is 400 mm, and the side length of the small plate pad 40 is 390 mm, precisely matching the 380 mm specification laminate 20 for a perfect fit.
[0039] In some embodiments, the height of the fencing structure 11 is 4-10mm, and in this embodiment it is 5mm, with a thickness consistent with the corresponding pad, i.e., 5mm. In this embodiment, the fencing structure 11 and the corresponding pad are integrally formed to ensure the connection strength between the fencing structure and the pad, eliminating the risk of breakage.
[0040] In some embodiments, the corners of the large plate pad 10 and the small plate pad 40 are rounded by 1-3mm, and the edges are rounded by 0.3-1mm. In this embodiment, the corners are rounded by 2mm and the edges by 0.5mm. The rounded corners and edges completely eliminate the sharp edges of the pads, avoiding scratches on the silicone pad 50 and the vacuum sealing bag. This solves the problem of leakage caused by the sharp edges of traditional pads. The smooth edges also reduce the risk of operators being scratched during operation, improving operational safety.
[0041] In some embodiments, the laminate 20 is a 380mm green ceramic laminate, and the size (400mm) of the micro-adhesive film surface 21 matches the size (400mm) of the large plate pad 10. The laminate 20 is placed centrally within the large plate pad 10, and the four corners of the micro-adhesive film surface 21 are fixed with tape, ensuring both initial fixation and avoiding adhesive contamination caused by edge overflow. Correspondingly, the PET film 30 is 380mm in size. It is placed with the silicone oil side down on the unfilmed surface of the green ceramic laminate for lamination, ensuring that the PET film 30 is completely adhered to the surface of the green ceramic laminate without any protrusions. At the same time, it ensures that this surface of the laminate 20 is sufficiently smooth after isostatic pressing, facilitating subsequent processing.
[0042] In some embodiments, in step 4, the small plate pad 40 is placed centrally on the PET film 30, and the relative positions of the small plate pad 40 and the large plate pad 10 are fixed by tape, so that there is no relative movement between the green ceramic laminate and the two pads, which further ensures the uniformity of the force on the laminate 20 and reduces shrinkage deviation.
[0043] In some embodiments, the silicone pad 50 is square with a side length of 800-900mm; in this embodiment, it is 800mm. The silicone pad 50 is secured with tape to ensure even edges and no gaps, improving sealing and cushioning. Additionally, after the silicone pad 50 is wrapped, it must be ensured that there are no large gaps or protruding edges to prevent abnormalities during vacuum extraction. It should also not be too tight to avoid excessive internal stress that could cause abnormalities during isostatic pressing. This should also be considered during subsequent inspection after vacuum extraction of the sealed bag.
[0044] In some embodiments, step 7 involves checking that the encapsulation bag and its internal structure are free of foreign objects, excessively hard parts, structural damage, and any risk of leakage. Specifically, this can be achieved by confirming whether the internal environment reaches a near-vacuum level, whether there are any fixation failures and the resulting relative displacement of various structures. A comprehensive inspection can systematically eliminate various defects during the encapsulation process, avoiding problems such as substrate surface defects caused by foreign objects, uneven pressure caused by excessively hard parts, and leakage caused by structural damage, thus significantly improving the success rate of isostatic pressing.
[0045] In summary, the isostatic pressing encapsulation method for LTCC ceramic substrates provided by this invention, through the square cap structure design combining large and small plates, combined with the multiple protections of PET film 30, silicone pad 50 and vacuum sealing, effectively solves the problems of uneven shrinkage and easy breakage in traditional encapsulation methods. Moreover, it is simple to operate, low in cost, and suitable for large-scale automated production, providing stable and reliable process support for the preparation of LTCC ceramic substrates.
[0046] Obviously, those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the invention. Therefore, if these modifications and variations fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.
Claims
1. An isostatic pressing encapsulation method suitable for LTCC ceramic substrates, characterized in that, Includes the following steps: Step 1: Design two square metal pads with different side lengths, named the large pad and the small pad respectively; the four edges of the large pad and the small pad are respectively provided with a barrier structure perpendicular to the plate surface to form a square cover structure; Step 2: Obtain the laminate, one side of which is a micro-adhesive film surface and the other side is a non-film surface. Place the micro-adhesive film surface downwards inside the large board pad with the enclosure structure facing upwards. Step 3: Place an equally sized PET film on the unfilmed side of the laminate for lamination; Step 4: Place the small board pad with the fencing structure facing down on the PET film, clamp the laminate and fix it; Step 5: Cover and secure the overall structure formed in Step 4 with a silicone pad; Step 6: Place the overall structure formed in Step 5 into a vacuum-sealed bag and seal it. Step 7: After inspection, proceed with the isostatic pressing process.
2. The isostatic pressing encapsulation method for LTCC ceramic substrates as described in claim 1, characterized in that, The thickness of the large plate and the small plate is 3~8mm, and the difference in their side lengths is 5~20mm.
3. The isostatic pressing encapsulation method for LTCC ceramic substrates as described in claim 2, characterized in that, The side length of the large plate pad is 400mm, and the side length of the small plate pad is 390mm.
4. The isostatic pressing encapsulation method for LTCC ceramic substrates as described in claim 1, characterized in that, The height of the enclosure structure is 4~10mm, and the thickness is the same as that of the corresponding pad.
5. The isostatic pressing encapsulation method for LTCC ceramic substrates as described in claim 1 or 4, characterized in that, The enclosure structure and the corresponding base plate are integrally formed.
6. The isostatic pressing encapsulation method for LTCC ceramic substrates as described in claim 1, characterized in that, The corners of both the large and small pads are rounded by 1-3mm, and the edges are rounded by 0.3-1mm.
7. The isostatic pressing encapsulation method for LTCC ceramic substrates as described in claim 1, characterized in that, The stacked body is a 380mm green ceramic stacked body. The size of the micro-adhesive film surface matches the size of the large plate pad. The green ceramic stacked body is placed in the center inside the large plate pad, and the four corners of the micro-adhesive film surface are fixed with tape.
8. The isostatic pressing encapsulation method for LTCC ceramic substrates as described in claim 1, characterized in that, In step 4, the small plate pad is placed centered on the PET film, and the relative positions of the small plate pad and the large plate pad are fixed by tape.
9. The isostatic pressing encapsulation method for LTCC ceramic substrates as described in claim 1, characterized in that, The silicone pad is square with a side length of 800~900mm, and the silicone pad is fixed in a covered state by tape.
10. The isostatic pressing encapsulation method for LTCC ceramic substrates as described in claim 1, characterized in that, In step 7, the inspection includes confirming that the packaging bag and its internal structure are free of foreign objects, hard parts, structural damage, and there is no risk of leakage.