Three-dimensional packaging interlayer interconnection structure based on soft solder interconnection

By using soldering to the metallized layer in three-dimensional packaging, the problems of high-temperature intolerance of electronic materials, electrolyte corrosion and metal ball bonding are solved, and good low-temperature packaging and stable interconnection are achieved.

CN222851439UActive Publication Date: 2025-05-09SOUTHWEST CHINA RES INST OF ELECTRONICS EQUIP
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Patent Information

Application Number
CN202421786992.0
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-07-26
Publication Date
2025-05-09
Estimated Expiration
2034-07-26

AI Technical Summary

Technical Problem

The existing three-dimensional packaged interlayer interconnection structures have problems such as high temperature intolerance of electronic materials, electrolyte corrosion chips, and metal balls are not easy to bond in micropores.

Method used

Using a solder-based interconnection structure, interlayer interconnection is achieved by setting interconnection through holes on the substrate and setting a metallization layer on its inner wall, and welding with the metallization layer using the solder to achieve interlayer interconnection.

Benefits of technology

It solves the problems of high temperature intolerance of electronic materials, electrolyte corrosion and metal ball bonding in three-dimensional packaging, and achieves good low-temperature packaging and stable interconnection, with a wide range of applications.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model relates to the technical field of microelectronic packaging, and provides a three-dimensional packaging interlayer interconnection structure based on soft solder interconnection, aiming at solving the problems that an electronic material is intolerant to high temperature, a chip is corroded by electrolyte and a metal ball is not easy to bond in a micropore in a three-dimensional packaging interlayer interconnection structure in the prior art. Comprising a plurality of stacked substrates, interconnection through holes are formed in the positions, needing to be interconnected with another substrate, of the substrates, interconnection bonding pads are arranged on the substrates, and the positions of the interconnection through holes in the upper substrate correspond to the positions of the interconnection bonding pads on the lower substrate; a metallization layer is arranged on the inner wall of the interconnection through hole, soft solder is arranged in the interconnection through hole, the side face of the soft solder is welded to the metallization layer, and the bottom face of the soft solder is welded to the interconnection bonding pad on the lower layer substrate; according to the utility model, soft solder is adopted for welding, so that not only is the advantage of low-temperature packaging realized, but also electrolyte is not needed, the chip and other packaging materials are prevented from being corroded by the electrolyte, stable interconnection of micropores can be realized, and the practicability is high.
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Description

Technical Field

[0001] The utility model relates to the technical field of microelectronic packaging, in particular to a three-dimensional packaging interlayer interconnection structure based on solder interconnection. Background Art

[0002] Microelectronic packaging technology continues to develop in the direction of miniaturization and high concentration. The main integration technologies include chip stacking and substrate stacking. Chip stacking includes TSV (through silicon via) interconnection technology, and substrate stacking mainly includes ball grid array technology.

[0003] At present, the interconnection structure between layers of three-dimensional packaging mainly adopts the LTCC process, which involves drilling holes and grouting on the raw ceramic sheet, and then using a high-temperature (usually greater than 650 degrees) sintering method to achieve interlayer interconnection. The second is the electroplating interlayer interconnection of the PCB board. The disadvantages of the above process are: the interconnection temperature of the slurry injection sintering of the LTCC process is relatively high, and many electronic materials cannot tolerate it. The electroplating interlayer interconnection of the PCB board uses various acids or salts as electrolytes for electroplating interconnection. The electrolyte will corrode the chip and other packaging materials, and the chip embedding process cannot be realized.

[0004] Patent CN116469779A discloses a three-dimensional package interlayer interconnection method and structure, which solves the problem of high temperature and electrolyte corrosion of chips. The structure has a good low-temperature stacking advantage. During the process, ultrasonic bonding of the interconnected metal balls is required to deform the metal balls to achieve interconnection. However, when facing smaller microholes during operation, this technology is not universal, and the bonding knife is prone to breakage or failure to bond. Utility Model Content

[0005] The utility model aims to provide a three-dimensional packaging interlayer interconnection structure based on soft solder interconnection, so as to solve the problems in the prior art of the three-dimensional packaging interlayer interconnection structure that electronic materials cannot tolerate high temperatures, electrolyte corrodes chips, and metal balls are difficult to bond in micropores.

[0006] The utility model is realized by adopting the following technical solutions:

[0007] The utility model provides a three-dimensional package interlayer interconnection structure based on solder interconnection, comprising a plurality of stacked substrates, wherein interconnection through holes are provided at positions where the substrates need to be interconnected with another substrate, interconnection pads are provided on the substrates, and the positions of the interconnection through holes on the upper substrates correspond to the positions of the interconnection pads on the lower substrates;

[0008] The inner wall of the interconnection through hole is provided with a metallization layer, and soft solder is provided in the interconnection through hole. The side surface of the soft solder is welded to the metallization layer, and the bottom surface of the soft solder is welded to the interconnection pad on the lower substrate.

[0009] As the preferred technical solution:

[0010] The solder is alloy solder or single metal solder.

[0011] As the preferred technical solution:

[0012] An interconnection cap brim is arranged around the interconnection through hole, the interconnection cap brim is ring-shaped, and the interconnection cap brim is welded to the metallization layer.

[0013] As the preferred technical solution:

[0014] The inner diameter of the interconnection cap brim is the same as the diameter of the interconnection through hole, and the width of the interconnection cap brim is one quarter to one half of the diameter of the interconnection through hole.

[0015] As the preferred technical solution:

[0016] The interconnect cap edge is made of the same material as the metallization layer.

[0017] As the preferred technical solution:

[0018] The conductive leads of the interconnect pads are processed with a solder resist layer.

[0019] As the preferred technical solution:

[0020] The three-dimensional packaging interlayer interconnection structure comprises a top plate, a bottom plate and an interconnection plate arranged between the top plate and the bottom plate, wherein the top plate, the interconnection plate and the bottom plate are arranged in a stacked manner.

[0021] As the preferred technical solution:

[0022] External connection soft solder is arranged in the interconnection through holes on the bottom plate, and interconnection soft solder is arranged in the interconnection through holes on the top plate and the interconnection plate.

[0023] As the preferred technical solution:

[0024] The three-dimensional packaging interlayer interconnection structure is a multi-layer interconnection through-hole direct connection structure or an interlayer staggered hole interconnection structure.

[0025] As the preferred technical solution:

[0026] A ground wire or a shielding layer is arranged on the substrate.

[0027] In summary, due to the adoption of the above technical solution, the beneficial effects of the utility model are:

[0028] The three-dimensional packaging interlayer interconnection structure of the utility model adopts the soft solder welding method, which solves the problems of high temperature intolerance, electrolyte corrosion and difficult bonding of electronic materials faced by three-dimensional packaging, enriches the interlayer interconnection means of three-dimensional packaging, and makes the process more practical.

[0029] The three-dimensional packaging interlayer interconnection structure of the utility model has good interconnection effect, not only has good low-temperature packaging advantages, but also does not need to use electrolyte, thus avoiding corrosion of chips and other packaging materials by electrolyte, and also overcomes the problem that the metal ball bonding wedge is prone to breakage or failure to bond in smaller microholes. It has a wide range of applications, can achieve stable interconnection for smaller microholes, and has high practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of the three-dimensional packaging interlayer interconnection structure based on solder interconnection described in the utility model.

[0031] Figure 2 It is a cross-sectional schematic diagram of the three-dimensional packaging interlayer interconnection structure based on solder interconnection described in the utility model.

[0032] Icon: 1-base plate, 2-interconnection plate, 3-top plate, 4-solder mask, 5-interconnection solder, 6-interconnection pad, 7-interconnection through hole, 8-ground wire or shielding layer, 9-interconnection cap edge, 10-external connection solder. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the utility model clearer, the technical solution in the embodiments of the utility model will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0034] Example 1

[0035] like Figure 1 and Figure 2 As shown, this embodiment proposes a three-dimensional package interlayer interconnection structure based on solder interconnection, including multiple stacked substrates, where the substrate needs to be interconnected with another substrate and an interconnection through hole 7 is provided. The material of the substrate includes but is not limited to ceramic, silicon, glass, FR4 and sapphire. The substrate is provided with a ground wire or shielding layer 8, which can improve the electromagnetic compatibility and signal integrity of the circuit and reduce the impact of electromagnetic interference.

[0036] In this embodiment, the substrate is an alumina ceramic substrate with a thickness of 0.38 mm. Thin-film laser holes are opened at locations where the substrate needs to be interconnected according to the circuit structure, and the opening diameter is 0.4 mm.

[0037] In this embodiment, the three-dimensional packaging interlayer interconnection structure based on soft solder interconnection includes five substrates, namely a top plate 3, a bottom plate 1, and three interconnection plates 2 arranged between the top plate 3 and the bottom plate 1. The top plate 3, the interconnection plates 2 and the bottom plate 1 are arranged in a stacked manner.

[0038] The substrate is provided with corresponding circuits and interconnection pads 6 according to the circuit structure. The position of the interconnection through hole 7 on the upper substrate corresponds to the position of the interconnection pad 6 on the lower substrate. The error between the interconnection through hole 7 and the corresponding interconnection pad 6 does not exceed 5% to 10% of the diameter of the interconnection through hole 7. The diameter of the interconnection pad 6 is 1.2 times the diameter of the interconnection through hole 7.

[0039] A solder resist layer 4 is processed on the conductive lead-out end of the interconnection pad 6, and the solder resist layer 4 is located between the interconnection pad 6. The material of the solder resist layer 4 includes but is not limited to solder resist green oil, solder resist groove and heterogeneous metal solder resist layer 4 and the like.

[0040] The inner wall of the interconnection through hole 7 is provided with a metallization layer, and the material of the metallization layer includes but is not limited to plating layers such as gold, silver, copper, nickel, indium, and tin.

[0041] An interconnection brim 9 is arranged around the interconnection through hole 7. The interconnection brim 9 is annular, the inner diameter of the interconnection brim 9 is the same as the diameter of the interconnection through hole 7, and the width of the interconnection brim 9 is one quarter to one half of the diameter of the interconnection through hole 7. The interconnection brim 9 is welded to the metallization layer. The material of the interconnection brim 9 is the same as that of the metallization layer.

[0042] Soft solder is arranged in the interconnection through hole 7. The soft solder refers to a material with a melting temperature lower than 450°C.

[0043] In this embodiment, the solder used is alloy solder or single metal solder including but not limited to gold-tin, tin-lead, indium-lead, indium-silver, tin-silver-copper, etc., and has a melting point of 120 to 400 degrees.

[0044] External connection solder 10 is arranged in the interconnection through hole 7 on the bottom plate 1 , and interconnection solder 5 is arranged in the interconnection through holes 7 on the top plate 3 and the interconnection plate 2 .

[0045] The side surface of the solder in the interconnection through hole 7 on each substrate is welded and interconnected with the metallization layer on the inner wall of the interconnection through hole 7 on the substrate; the bottom surface of the solder is welded and interconnected with the interconnection pad 6 of the lower substrate to achieve interlayer interconnection.

[0046] In this embodiment, the solder paste of the soft solder is dotted into the interconnection through hole 7 by a dispensing device (dispensing is generally used for large holes, and injection or printing is used for small holes), and then heated in a vacuum welding furnace. After the solvent, wetting agent, etc. in the solder paste are volatilized, the solder paste is heated to melt. The solder paste melts at high temperature in the interconnection through hole 7 to form a columnar structure. The columnar surface of the columnar structure is welded and interconnected with the metallization layer on the inner wall of the interconnection through hole 7 on the substrate. When the solder paste melts at high temperature, the solder paste at the bottom of the interconnection through hole 7 will flow to the gap between the interconnection pad 6 and the interconnection cap edge 9, and the solder paste is welded and interconnected with the interconnection pad 6 of the lower substrate. The solder resist layer 4 can effectively limit the solder paste of the soft solder within the interconnection range.

[0047] By adopting the above structure, two interlayer interconnection modes, namely, direct connection of multilayer interconnection through holes 7 and interconnection of interlayer staggered holes, can be formed.

[0048] The three-dimensional packaging interlayer interconnection structure of this embodiment adopts soft solder welding, which solves the problems of high temperature intolerance, electrolyte corrosion and difficult bonding of electronic materials faced by three-dimensional packaging, enriches the interlayer interconnection means of three-dimensional packaging, and makes the process more practical.

[0049] Furthermore, an interlayer continuity test was carried out on the three-dimensional packaging interlayer interconnection structure using gold-tin as the soft solder. A total of 3200 interconnection points on the four-layer substrate were interconnected and interoperable, and the interconnection effect was obvious. There was no solder hanging off the hole, which verified the interconnection effect of the three-dimensional packaging interlayer interconnection structure provided by the utility model. It not only has the advantage of good low-temperature packaging, but also does not require the use of electrolyte, thus avoiding corrosion of the chip and other packaging materials by the electrolyte. It also overcomes the problem that the metal ball bonding splitter is prone to breakage or cannot be bonded in smaller microholes. It has a wide range of applications, can achieve stable interconnection for smaller microholes, and is highly practical.

[0050] The method for interconnecting three-dimensional packaging layers based on solder welding interconnection comprises the following steps:

[0051] S1: Process the interconnection board 2, the bottom board 1 and the top board 3 according to the design requirements, and install the embedded chips and components of the interconnection board 2 as required;

[0052] Specifically, this embodiment uses 5 alumina ceramic substrates with a thickness of 0.38 mm, which are used as the top plate 3, the bottom plate 1 and three interconnection plates 2 respectively; according to the circuit structure, the corresponding circuit, the interconnection pad 6, the interconnection through hole 7 and the interconnection cap edge 9 are prepared on the ceramic substrate, and the inner wall of the interconnection through hole 7 and the outer side of the ceramic substrate are plated with gold in the process, and the gold plating thickness is 4 microns; according to the circuit structure, the ceramic substrate is subjected to thin-film laser drilling at the place where interconnection is required to be performed, and the interconnection through hole 7 is obtained, and the hole diameter is 0.4 mm; according to the circuit requirements, the chips or components that need to be embedded are subjected to patch or eutectic welding to achieve interconnection within the board and pass the test, and the circuit performance is ensured to be placed in order for standby;

[0053] Prepare solder paste, limit fixture, vacuum soldering furnace and automatic glue dispenser for soft solder;

[0054] S2: Place the bottom plate 1 into the limiting fixture, place the bottom plate 1 on the bottom layer, then place an interconnection board 2 on the bottom plate 1, adjust the limiting fixture to align the interconnection through hole 7 of the interconnection board 2 with the interconnection pad 6 on the bottom plate 1, and press the interconnection board 2 and the bottom plate 1 tightly; wherein the limiting fixture is used as a positioning device, which includes a table and pins installed on the table, and the interconnection board 2 is aligned by the pins;

[0055] S3: Put the limit fixture into the fully automatic glue dispensing machine, and the fully automatic glue dispensing machine dispenses solder paste for interconnection welding into the interconnection through hole 7 (large holes are generally dispensed, and small holes are injected or printed); this embodiment uses gold-tin paste with a melting point of 280 degrees;

[0056] S4: according to step S2 and step S3, continue to stack and press the ceramic substrates, and during the stacking process, inject solder paste into the interconnection through holes 7 of the ceramic substrates until the stacking of the top plate 3 is completed;

[0057] S5: Place the limit fixture into the vacuum eutectic furnace and set the welding curve. When setting the curve, a heating period is set before the welding slurry melts to volatilize the solvent, wetting agent, dispersant and other additives in the welding slurry. After the various solvents in the welding slurry volatilize, a vacuum is set to prevent various volatilized gases from being sealed into the product. Then set the melting temperature of the welding slurry, start the vacuum eutectic furnace to run and heat, and vacuum weld the compacted products.

[0058] S6: After the vacuum eutectic furnace is finished running, take out the product and disassemble the limit fixture;

[0059] S6: The product is placed with indium lead balls using the same process as the interlayer interconnection, with a melting point of 175 degrees;

[0060] S7: Conduct electrical testing and pack and store after passing the test.

[0061] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A three-dimensional packaging interlayer interconnection structure based on solder interconnection, characterized in that: It comprises a plurality of stacked substrates, wherein interconnection through holes are provided at positions where the substrates need to be interconnected with another substrate, interconnection pads are provided on the substrates, and the positions of the interconnection through holes on the upper substrate correspond to the positions of the interconnection pads on the lower substrate; The inner wall of the interconnection through hole is provided with a metallization layer, and soft solder is provided in the interconnection through hole. The side surface of the soft solder is welded to the metallization layer, and the bottom surface of the soft solder is welded to the interconnection pad on the lower substrate.

2. The three-dimensional packaging interlayer interconnection structure based on solder interconnection according to claim 1, characterized in that: The solder is alloy solder or single metal solder.

3. The three-dimensional package interlayer interconnection structure based on solder interconnection according to claim 1, characterized in that: An interconnection brim is arranged around the interconnection through hole, the interconnection brim is in a ring shape, and the interconnection brim is welded to the metallization layer.

4. The three-dimensional packaging interlayer interconnection structure based on solder interconnection according to claim 3, characterized in that: The inner diameter of the interconnection cap brim is the same as the diameter of the interconnection through hole, and the width of the interconnection cap brim is one quarter to one half of the diameter of the interconnection through hole.

5. The three-dimensional packaging interlayer interconnection structure based on solder interconnection according to claim 3, characterized in that: The interconnect cap edge is made of the same material as the metallization layer.

6. The three-dimensional package interlayer interconnection structure based on solder interconnection according to claim 1, characterized in that: The conductive leads of the interconnect pads are processed with a solder resist layer.

7. The three-dimensional package interlayer interconnection structure based on solder interconnection according to claim 1, characterized in that: The three-dimensional packaging interlayer interconnection structure comprises a top plate, a bottom plate and an interconnection plate arranged between the top plate and the bottom plate, wherein the top plate, the interconnection plate and the bottom plate are arranged in layers.

8. The three-dimensional package interlayer interconnection structure based on solder interconnection according to claim 7, characterized in that: External connection soft solder is arranged in the interconnection through holes on the bottom plate, and interconnection soft solder is arranged in the interconnection through holes on the top plate and the interconnection plate.

9. The three-dimensional package interlayer interconnection structure based on solder interconnection according to claim 1, characterized in that: The three-dimensional packaging interlayer interconnection structure is a multi-layer interconnection through-hole direct connection structure or an interlayer staggered hole interconnection structure.

10. The three-dimensional package interlayer interconnection structure based on solder interconnection according to claim 1, characterized in that: A ground wire or a shielding layer is arranged on the substrate.