High-density BGA packaging ceramic substrate based on HTCC technology and manufacturing method thereof

Abstract

The invention discloses a high-density BGA packaging ceramic substrate based on an HTCC technology and a manufacturing method thereof, and belongs to the field of SIP shell manufacturing. The substrate comprises three-dimensional interconnected display micropores, a BGA bonding pad ball mounting area, a chip pasting area and a bonding area. The manufacturing method comprises the following steps: (1) manufacturing the three-dimensional interconnected display micropores: pretreating a green ceramic chip, manufacturing the micropores, metalizing and grouting the micropores, recycling metalized slurry, and flattening; and (2) manufacturing a ball mounting area, a bonding area and a bonding area of the BGA bonding pad: forming a ceramic matrix and plating a substrate. The method has the following advantages: (1) the micropore taper is small, the hole wall roughness is low, and the interconnection performance is improved; (2) a special through printing template is not needed, the through printing cost is saved, and batch production can be realized; (3) recycling of redundant slurry is realized, the cost is reduced, (4) zero deformation in the transportation process is realized, (5) the risk of generating gaps among multiple layers of green ceramic chips is reduced, and the quality and the performance stability of interconnected through holes of products are ensured.

Description

Technical Field

[0001] The invention belongs to the field of SIP shell manufacturing, and in particular relates to a high-density BGA package ceramic substrate based on HTCC technology and a manufacturing method thereof. Background Art

[0002] BGA (Ball Grid Array) is an SMT (Surface Mount Technology) packaging technology that achieves three-dimensional electrical interconnection with the circuit board through an array of solder balls on the bottom of the package. It offers high performance, high integration, and high reliability, making it the preferred packaging solution for complex SIP (System-in-Package) housings in applications such as aerospace and high-end electronic equipment, where reliability is critical. As the integration requirements for high-end SIP housings continue to increase, the pitch of the BGA package array pads has been reduced from the conventional 0.8-1.5 mm to 0.5 mm or less. This places higher demands on the internal interconnect structure of the ceramic substrate, requiring the integration of more high-density interconnect microvias such as through-holes, blind vias, and buried vias to ensure the integrity and stability of signal transmission.

[0003] Currently, the HTCC process is generally used in the manufacture of BGA package ceramic substrates. Its core process includes drilling, metallization slurry injection, leveling, lamination, and hot cutting. This process has the following technical bottlenecks in achieving high-density interconnect micro-hole processing: 1) Micro-hole molding quality defects: processing defects such as large hole wall taper and obvious hole mouth burrs lead to poor micro-hole morphology consistency; 2) High template manufacturing costs: The current template omission printing technology requires customized templates for different hole position patterns. The R&D cost of a single template is high, and pattern changes require re-plate making. 3) Insufficient production flexibility: Frequent template changes are required for multi-layer, small-batch production, resulting in high time consumption for each changeover and insufficient equipment utilization. 4) Metallization grouting yield issues: The green ceramic sheet is prone to shape and positional displacement during operation, leading to template misalignment, grouting defects, and void defects. 5) Surface contamination risk: After grouting, the green ceramic sheet lacks effective surface protection, which is prone to spatter contamination, leading to a decrease in the insulation resistance of the ceramic substrate. 6) Green ceramic sheet deformation control: The compaction pressure during the leveling process causes localized warping and deformation of the green ceramic sheet, affecting the inter-layer alignment accuracy. These processing difficulties have seriously restricted the further development of high-density interconnect microvias within BGA ceramic substrates. Summary of the Invention

[0004] Purpose of the invention: The first purpose of the present invention is to provide a high-density BGA package ceramic substrate based on the HTCC process that can solve the problem of internal dense interconnection micro-hole molding defects, improve the yield rate, increase production efficiency, and is suitable for mass production. The second purpose of the present invention is to provide a manufacturing method for the above-mentioned high-density BGA package ceramic substrate based on the HTCC process.

[0005] Technical solution: The high-density BGA packaging ceramic substrate based on the HTCC process described in the present invention includes three-dimensional interconnected micropores inside the ceramic substrate, a BGA pad planting area on the back of the ceramic substrate, and a chip pasting area and bonding area on the front of the ceramic substrate.

[0006] Furthermore, the taper of the three-dimensionally interconnected micropores is less than 1%, and the surface roughness of the inner wall of the pores is less than 0.5 μm.

[0007] The manufacturing method of the high-density BGA package ceramic substrate of the present invention comprises the following steps:

[0008] (1) Fabrication of three-dimensional interconnected micropores inside ceramic substrates:

[0009] (11) Pretreatment of green ceramic sheets: Cover the front of a single green ceramic sheet with two layers of micro-mucosa and the back with a single layer of micro-mucosa;

[0010] (12) Micropore production: The coated raw ceramic sheet is processed by laser micropore processing technology to form a through-hole structure;

[0011] (13) Microporous metallization grouting: filling the raw ceramic sheet punched in step (12) with metallization slurry;

[0012] (14) metallization slurry recovery; placing the green ceramic sheet after slurry injection in step (13) on a vacuum suction table to recover excess slurry on the surface;

[0013] (15) Flattening treatment: After the green ceramic sheet treated in step (14) is left to solidify, the first layer of micro-viscosity is removed, and the slurry protrusions on the surface caused by the filling of holes are removed; the internal three-dimensional interconnected micro-pores are fabricated;

[0014] (2) Fabrication of the BGA pad ball planting area on the back of the ceramic substrate, the chip pasting area and the bonding area on the front of the ceramic substrate:

[0015] (21) Ceramic matrix forming: printing internal interconnection circuits and BGA pad patterns on the back of the green ceramic sheet processed in step (15); laminating and pressing multiple layers of green ceramic sheets, cutting them into single green sheets, and forming a three-dimensional ceramic matrix through a co-firing process;

[0016] (22) Substrate plating: depositing a nickel-gold composite layer on a preset area of ​​the ceramic substrate after sintering in step (21) by chemical replacement, coating a photoresist protective layer on the BGA pad ball planting area by spraying or spot coating, curing to form a mask, establishing electrical connection of the thick gold area by gold wire bonding, thickening the nickel-gold layer by electroplating, removing the photoresist, completing the differentiated metallization treatment of the BGA pad ball planting area and the bonding area, and completing the production of the BGA pad ball planting area on the back of the ceramic substrate, the chip pasting area and the bonding area on the front of the ceramic substrate.

[0017] Furthermore, in step (11), the outer dimensions of the micro-mucosa are the same as those of the raw porcelain sheet, the micro-mucosa comprises a PET film and an adhesive, the total thickness is 0.04-0.07 mm, the surface roughness Ra of the PET film is 0.4-1.6 μm, and the adhesion is 5-12 g / 25 mm.

[0018] Furthermore, in step (12), the laser micro-hole processing technology uses ultraviolet nanosecond or femtosecond laser equipment, selects gradient laser energy, first sets the pulse width to 250-400ms, the repetition frequency to 70-100kHz, and the processing speed to 400-600mm / s to complete the micro-mucosal processing on the surface of the raw porcelain piece; then sets the pulse width to 150-250ms, the repetition frequency to 40-70kHz, and the processing speed to 100-300mm / s, and introduces nitrogen-assisted purge after the micro-hole processing is completed to improve the roughness of the hole wall.

[0019] Furthermore, in step (13), the metallization slurry is a tungsten slurry with a solid content of 60.0-90.0wt%, a tungsten powder particle size of 0.2-10.0μm, and a slurry viscosity of 30-300KCP; the grouting equipment used during filling does not require alignment, and the scraper pressure is set to 0.28-0.38Mpa, the speed is 4-8inches / sec, the scraper height is 75-120μm, and the number of repetitions is (1-3)n to complete the green tile interconnection through-hole grouting.

[0020] Furthermore, in step (14), the vacuum suction force is 20-30 MPa.

[0021] Furthermore, in step (15), the static curing time is 1-2 hours.

[0022] Furthermore, in step (21), the HTCC co-firing process is adopted to carry out sintering in a nitrogen-hydrogen mixed atmosphere, and the maximum sintering temperature is set to 1600±30° C. to form a three-dimensional ceramic matrix.

[0023] Furthermore, in step (22), the thickness of the nickel layer is 3 μm-8.9 μm, the thickness of the thick gold area plating is 1.3 μm-5.7 μm; and the thickness of the thin gold layer plating on the back BGA pad is 0.03 μm-0.3 μm.

[0024] Beneficial effects: Compared with the prior art, the present invention has the following significant effects: (1) By pasting micro-mucosa on both sides of the raw porcelain sheet, deformation during the conveyor processing is effectively prevented; (2) The micropore taper is less than 1% by controlling the energy gradient during the punching process, and nitrogen-assisted purge is introduced to make the hole wall roughness less than 0.5 μm; (3) There is no need to make a special stencil during the hole filling process, which reduces production costs, improves production efficiency, and is suitable for batch production; at the same time, there is no need to consider the positioning accuracy error of the hole filling equipment, which avoids insufficient slurry injection, forming voids inside the micropores, and affecting electrical performance and packaging reliability; (4) Excess slurry can be recycled and reused, which reduces slurry costs, and micro-mucosa protection prevents slurry contamination and debonding; (5) No leveling treatment is required after hole filling, which reduces the risk of local deformation. After removing the raised slurry on the back of the second micro-mucosa of the raw porcelain sheet, the risk of gaps between multiple layers of raw porcelain sheets is reduced, ensuring the appearance quality and performance of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic structural diagram of a high-density BGA package ceramic substrate based on the HTCC process in Example 1;

[0026] Figure 2 This is a diagram of the micro-hole grouting structure of the ceramic-based internal interconnection of the high-density BGA package based on the HTCC process in Example 1;

[0027] Figure 3 This is a diagram of the method for manufacturing internal interconnection microvias of a high-density BGA package ceramic substrate based on the HTCC process in Example 1. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below with reference to the embodiments and accompanying drawings.

[0029] Example 1: Figure 1 As shown, the high-density BGA packaging ceramic substrate based on the HTCC process includes three-dimensional interconnected micro-holes inside the ceramic substrate, a BGA pad planting area on the back of the ceramic substrate, and a chip pasting area and bonding area on the front of the ceramic substrate. The taper of the three-dimensional interconnected micro-holes is less than 1%, and the surface roughness of the inner wall of the hole is less than 0.5μm.

[0030] The manufacturing method of the high-density BGA package ceramic substrate comprises the following steps:

[0031] (1) Pretreatment of green ceramic sheets: Fix the green ceramic sheet on a vacuum suction table. Use a cut micro-mucosa with the same dimensions as the green ceramic sheet and apply the micro-mucosa to the perforated surface and the back surface. Apply two micro-mucosa to the perforated surface and one micro-mucosa to the back surface to ensure smoothness and bubble-free. The total thickness of the micro-mucosa, including the PET film and the adhesive, is 0.07 mm. The surface roughness of the PET film is Ra (1.6) μm, and the adhesion is 12 g / 25 mm.

[0032] (2) Micropore production: A substrate matching the processing pattern is placed on the table of the ultraviolet nanosecond laser equipment, where the substrate aperture is slightly larger than the actual aperture. After adjusting the laser parameters, a single coated raw ceramic sheet is placed on the substrate, and different parameters are selected to process the raw ceramic sheet in batches. First, the pulse width is set to 250ms, the repetition frequency is 100kHz, and the processing speed is 400mm / s to complete the micro-viscosity processing on the surface of the raw ceramic sheet; then the pulse width is set to 200ms, the repetition frequency is 50kHz, and the processing speed is 150mm / s to complete the micropore processing of the entire coated raw ceramic sheet; after the processing is completed, nitrogen purge is introduced to improve the roughness of the hole wall;

[0033] (3) Microporous metallization grouting: Place the punched green ceramic sheet on the table of the hole filling equipment, select tungsten slurry with a solid content of 60.0wt%, a tungsten powder particle size of 1μm, and a slurry viscosity of 100KCP. The equipment does not need to be aligned, set the scraper pressure to 0.3Mpa, the speed to 4inches / sec, the scraper height to 75μm, and the number of repetitions to 2n to complete the green ceramic sheet interconnection microporous grouting, such as Figure 2 As shown;

[0034] (4) Metallization slurry recovery: After completing the microporous grouting of the green ceramic sheet, place it on the vacuum suction table, set the vacuum suction force to 20 MPa, and recover the excess slurry on the micro-mucosa. Figure 3 As shown;

[0035] (5) Removal of surface raised slurry: After the green porcelain tape is left to stand for 2 hours, the slurry on the surface of the green porcelain sheet after grouting is solidified, the first micro-mucosal film on the surface is peeled off, and the excess raised slurry on the surface of the second micro-mucosal film is removed with a rubber scraper to complete the interconnected microporous grouting;

[0036] (6) Ceramic matrix forming: After completing the above steps, the internal interconnection circuits and the BGA pad pattern on the back of the green ceramic sheet are printed; the multi-layer green ceramic sheets are laminated and pressed, cut into single green sheets, and sintered in a nitrogen-hydrogen mixed atmosphere through the HTCC co-firing process, with the maximum sintering temperature set at 1615°C to form a three-dimensional ceramic matrix;

[0037] (7) Substrate plating: A nickel-gold composite layer is deposited on the ceramic substrate by chemical replacement. A photoresist protective layer is applied to the BGA ball planting area and cured to form a mask. Electrical connections are established in the thick gold area by gold wire bonding. The nickel-gold layer is thickened by electroplating. The photoresist is removed to ensure that the substrate nickel layer thickness is 3μm-6μm and the thick gold area coating thickness is 2μm-5μm. The thickness of the thin gold layer on the back BGA pad is 0.03μm-0.15μm. The substrate plating is completed.

[0038] Through the above-mentioned specific embodiments, the micropore taper of the internal interconnection through-holes of the high-density BGA package ceramic substrate can be made less than 1%, and the surface roughness of the inner wall of the hole can be less than 0.5 μm. No special stencil is required, which saves stencil costs, realizes the recycling and reuse of excess slurry, and reduces the cost of auxiliary materials by 25%. The cost of production raw materials is reduced by 72%, the production efficiency is improved by 54%, and the production cycle is shortened by 38%.

Claims

1. A high-density BGA package ceramic substrate based on HTCC process, characterized in that: It includes three-dimensional interconnected micropores inside the ceramic substrate, BGA pad ball planting area on the back of the ceramic substrate, and chip pasting area and bonding area on the front of the ceramic substrate.

2. The high-density BGA package ceramic substrate according to claim 1, characterized in that: The taper of the three-dimensional interconnected micropores is less than 1%, and the surface roughness of the inner wall of the pores is less than 0.5 μm.

3. A method for manufacturing a high-density BGA package ceramic substrate according to claim 1, characterized in that: The following steps are involved: (1) Fabrication of three-dimensional interconnected micropores inside ceramic substrates: (11) Pretreatment of green ceramic sheets: Cover the front of a single green ceramic sheet with two layers of micro-mucosa and the back with a single layer of micro-mucosa; (12) Micropore production: The coated raw ceramic sheet is processed by laser micropore processing technology to form a through-hole structure; (13) Microporous metallization grouting: filling the raw ceramic sheet punched in step (12) with metallization slurry; (14) metallization slurry recovery; placing the green ceramic sheet after slurry injection in step (13) on a vacuum suction table to recover excess slurry on the surface; (15) Flattening treatment: After the green ceramic sheet treated in step (14) is left to solidify, the first layer of micro-viscosity is removed, and the slurry protrusions on the surface caused by the filling of holes are removed; the internal three-dimensional interconnected micro-pores are fabricated; (2) Fabrication of the BGA pad ball planting area on the back of the ceramic substrate, the chip pasting area and the bonding area on the front of the ceramic substrate: (21) Ceramic matrix forming: printing internal interconnection circuits and BGA pad patterns on the back of the green ceramic sheet processed in step (15); laminating and pressing multiple layers of green ceramic sheets, cutting them into single green sheets, and forming a three-dimensional ceramic matrix through a co-firing process; (22) Substrate plating: depositing a nickel-gold composite layer on a preset area of ​​the ceramic substrate after sintering in step (21) by chemical replacement, coating a photoresist protective layer on the BGA pad ball planting area by spraying or spot coating, curing to form a mask, establishing electrical connection of the thick gold area by gold wire bonding, thickening the nickel-gold layer by electroplating, removing the photoresist, completing the differentiated metallization treatment of the BGA pad ball planting area and the bonding area, and completing the production of the BGA pad ball planting area on the back of the ceramic substrate, the chip pasting area and the bonding area on the front of the ceramic substrate.

4. The manufacturing method according to claim 3, characterized in that In step (11), the outer dimensions of the micro-mucosa are the same as those of the raw porcelain sheet. The micro-mucosa comprises a PET film and an adhesive, with a total thickness of 0.04-0.07 mm, a surface roughness Ra of the PET film of 0.4-1.6 μm, and an adhesive force of 5-12 g / 25 mm.

5. The manufacturing method according to claim 3, characterized in that In step (12), the laser micro-hole processing technology uses ultraviolet nanosecond or femtosecond laser equipment, selects gradient laser energy, first sets the pulse width to 250-400ms, the repetition frequency to 70-100kHz, and the processing speed to 400-600mm / s to complete the micro-mucosal processing on the surface of the raw porcelain piece; then sets the pulse width to 150-250ms, the repetition frequency to 40-70kHz, and the processing speed to 100-300mm / s, and introduces nitrogen-assisted purge after the micro-hole processing is completed.

6. The manufacturing method according to claim 3, characterized in that In step (13), the metallization slurry is tungsten slurry, the solid content is 60.0-90.0wt%, the tungsten powder particle size is 0.2-10.0μm, and the slurry viscosity is 30-300KCP; the grouting equipment used during filling does not need to be aligned, the scraper pressure is set to 0.28-0.38Mpa, the speed is 4-8inches / sec, the scraper height is 75-120μm, the number of repetitions is (1-3)n, and the green tile interconnection through-hole grouting is completed.

7. The manufacturing method according to claim 3, characterized in that In step (14), the vacuum suction force is 20-30 MPa.

8. The manufacturing method according to claim 3, characterized in that In step (15), the static curing time is 1-2 hours.

9. The manufacturing method according to claim 3, characterized in that: In step (21), the HTCC co-firing process is adopted to carry out sintering in a nitrogen-hydrogen mixed atmosphere, and the maximum sintering temperature is set to 1600±30° C. to form a three-dimensional ceramic matrix.

10. The manufacturing method according to claim 3, characterized in that: In step (22), the thickness of the nickel layer is 3 μm-8.9 μm, the thickness of the thick gold area plating is 1.3 μm-5.7 μm; the thickness of the thin gold layer plating of the back BGA pad is 0.03 μm-0.3 μm.

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