Glass substrate and use thereof

Abstract

The application provides a glass substrate and application thereof, which comprises at least one through hole, a composite resin filled in the through hole, and a first metal layer between the through hole and the composite resin; wherein the roughness Ra of the first metal layer is greater than or equal to 1 micrometer; and the thermal expansion coefficient of the composite resin is 8-15 ppm / ℃. The roughness of the first metal layer is increased to Ra greater than or equal to 1 micrometer, so that a dendritic microstructure is formed on the surface of the first metal layer, a three-dimensional mechanical interlocking structure is formed between the first metal layer and the composite resin, the resin is effectively anchored in the through hole, and the interface bonding strength is significantly enhanced. On this basis, the thermal expansion coefficient of the composite resin is controlled, so that the thermal expansion characteristics of the dendritic structure and the glass substrate are more coordinated, and excessive stretching or shearing of the dendritic anchoring structure caused by a too large thermal expansion difference is avoided.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor packaging, and particularly relates to a glass substrate and its application. Background Technology

[0002] Through-Glass Via (TGV) technology is one of the core solutions for achieving three-dimensional integrated interconnection in advanced semiconductor packaging. It provides a critical path for electrical connections in high-density packaging by forming vertical vias on a glass substrate. The glass substrate itself possesses excellent dielectric properties, high insulation, and good thermal stability, giving this technology significant advantages in areas such as high-frequency RF chips, Mini / Micro LED display backplanes, and 2.5D / 3D packaging interposers. However, in the implementation of TGV technology, the quality of the via metallization directly determines the reliability of the overall package, becoming a key factor limiting its performance.

[0003] Current mainstream copper paste filling technologies have revealed several fundamental defects during application. After curing, copper paste generally exhibits excessive porosity, leading to significant fluctuations in conductivity. This makes it prone to electromigration failure under high temperature and humidity environments, resulting in product yields that fail to meet production requirements. Furthermore, the significant difference in thermal expansion coefficients between copper and glass makes them susceptible to interfacial cracking under temperature cycling conditions, hindering relevant reliability certifications. While existing resin filling solutions attempt to address these issues, their adhesion to the glass substrate is generally low, posing a challenge of insufficient interfacial reliability in practical applications. Summary of the Invention

[0004] To address the issues of thermal expansion coefficient mismatch and insufficient interfacial bonding in through-hole metallized structures, this invention provides a glass substrate and its application.

[0005] According to one aspect of the present invention, a glass substrate is provided, the glass substrate comprising at least one through hole and a composite resin filling the through hole, and a first metal layer further comprising between the through hole and the composite resin; wherein the roughness Ra of the first metal layer is ≥1μm; and the coefficient of thermal expansion of the composite resin is 8ppm / ℃~15ppm / ℃.

[0006] This invention improves the surface roughness of the first metal layer to Ra≥1μm, forming a dendritic microstructure that creates a three-dimensional mechanical interlocking structure with the composite resin. This effectively anchors the resin within the through-holes, significantly enhancing interfacial bonding strength. Furthermore, by controlling the coefficient of thermal expansion of the cured composite resin within the range of 8ppm / ℃ to 15ppm / ℃, the thermal expansion characteristics are more coordinated with the dendritic structure and the glass substrate. This effectively reduces thermal stress concentration at the interface during temperature changes, preventing excessive stretching or shearing of the dendritic anchoring structure due to large differences in thermal expansion. The synergistic effect of both ensures that the dendritic anchoring maintains a stable mechanical interlocking state under thermal cycling conditions, improving the long-term reliability of the glass substrate provided by this invention in temperature-varying environments.

[0007] Preferably, the coefficient of thermal expansion of the glass substrate is 3.2ppm / ℃ to 4.5ppm / ℃.

[0008] Preferably, the roughness of the first metal layer is 1 μm ≤ Ra ≤ 2 μm. Controlling the roughness and setting the surface roughness Ra of the first metal layer within this range is beneficial for forming a suitable dendritic structure, enabling a reliable three-dimensional mechanical interlock between the dendritic structure and the composite resin. If the roughness is too low, the dendritic structure will not develop sufficiently, resulting in a relatively limited anchoring effect; if the roughness is too high, it may affect the uniformity of resin filling, making it more difficult to control the porosity below 1%. Therefore, limiting the roughness within the above range helps to achieve a balance between anchoring strength and filling quality.

[0009] Preferably, the thickness of the first metal layer is 2μm to 8μm.

[0010] Preferably, the diameter of the through hole is 10μm to 250μm, and the aspect ratio is 1 to 15:1.

[0011] Preferably, the metal composition in the first metal layer includes at least one of copper, nickel, silver, and gold.

[0012] Preferably, the first metal layer is composed of copper.

[0013] Preferably, the composite resin includes a resin material, which includes at least one of cyanate ester resin, phenolic resin, bisphenol A type epoxy resin, and polyimide resin.

[0014] Preferably, the composite resin includes an inorganic filler, which includes at least one of aluminum nitride, boron nitride, and silicon dioxide.

[0015] Preferably, the composite resin includes a silane coupling agent.

[0016] Preferably, the composite resin includes a resin material and an inorganic filler, wherein the resin material and the inorganic filler satisfy at least one of the following conditions: (a) the resin material includes a cyanate ester resin and the inorganic filler includes silica; (b) the resin material includes a phenolic resin and the inorganic filler includes aluminum nitride and silica; (c) the resin material includes a bisphenol A type epoxy resin and the inorganic filler includes silica; (d) the resin material includes a polyimide resin and the inorganic filler includes boron nitride.

[0017] Preferably, in (a), the particle size of the silica used is 20 nm to 100 nm. The cyanate ester resin has a low viscosity, and using nano-sized silica can prevent sedimentation, achieve uniform dispersion, and form a dense nanocomposite structure after curing, effectively reducing CTE.

[0018] Preferably, in (b), the particle size of the silica used is 0.5 μm to 5 μm. Phenolic resins exhibit significant curing shrinkage; using micron-sized silica can serve as an effective volume filler and reinforcing phase, offering lower cost and providing good dimensional stability and thermal conductivity.

[0019] Preferably, in (c), the particle size of the silica used is 1μm to 10μm. This is the most common system. Micron-sized silica fillers can effectively reduce the CTE of epoxy resin, improve its thermomechanical properties, and the filling process is mature and easy to control.

[0020] Preferably, in (d), the silica particle size is 0.1 μm to 1 μm. This system has a high resin precursor viscosity, and the submicron-sized filler balances dispersibility and processability, preventing agglomeration and sedimentation. This particle size facilitates close packing, reduces microcracks and porosity caused by curing shrinkage, and improves interlayer density and reliability. Simultaneously, the large reinforcing interface effectively improves the thermomechanical stability and resistance to damp heat aging of the composite material, meeting the stringent requirements of high-frequency, high-speed packaging for the dielectric layer.

[0021] Preferably, the composite resin comprises, by weight percentage, 60%–80% resin material, 20%–40% inorganic filler, 10%–15% curing agent, and 0.5%–2% silane coupling agent.

[0022] To address the CAF (Conductivity-Affected Failure) problem that may occur in glass substrates containing through-holes during use, this solution employs an optimized material system design to establish an effective countermeasure mechanism. CAF failure typically manifests as copper ions migrating along the glass fiber-resin interface under humid conditions and electric fields, gradually forming conductive filaments and affecting the insulation performance between adjacent conductors. To suppress this process, this solution introduces a silane coupling agent and inorganic filler into the composite resin. The silane coupling agent forms stable Si-O-Cu covalent bonds with the copper dendrite surface, constructing a chemical bonding layer at the interface. This bonding strength is significantly superior to traditional physical bonding methods, effectively blocking the diffusion path of copper ions. Simultaneously, the inorganic filler added to the composite resin adsorbs free ions, further enhancing the resistance to ion migration. Through the synergistic effect of these mechanisms, the material system exhibits excellent anti-CAF performance in high-temperature and high-humidity environment tests, fully demonstrating its reliability in suppressing ion migration.

[0023] Preferably, the first metal layer covers the inner wall of the through hole and the area around the opening of the through hole; and / or, the upper surface of the glass substrate is covered with a second metal layer and the lower surface of the glass substrate is covered with a third metal layer.

[0024] Preferably, the thickness ratio is calculated as follows: first metal layer: second metal layer: third metal layer = 1:2~5:2~5.

[0025] Preferably, the thickness of the second metal layer is 5μm to 20μm.

[0026] Preferably, the thickness of the third metal layer is 5μm to 20μm.

[0027] By incorporating a first metal layer covering the inner wall of the via and the area surrounding the via opening, and combining it with second and third metal layers on the upper and lower surfaces of the glass substrate, a multilayer metal interconnect structure is formed. Furthermore, by controlling the thickness ratio of the first metal layer to the upper and lower surface metal layers, a suitable thickness relationship is maintained between the via metal layer and the surface metal layers. This helps optimize the uniformity of current distribution in both the vertical and horizontal directions, while also promoting effective heat dissipation along the multilayer metal paths. This optimized thickness ratio allows the via structure and the surface wiring layers to work synergistically in terms of conductivity and thermal management, thereby improving the overall electrical reliability and thermal stability of the structure.

[0028] Preferably, the glass substrate of the present invention is prepared by the following method: the surface of the glass substrate with through holes is roughened so that the roughness Ra of the inner wall of the through holes is ≥1μm; then a first metal layer is formed on the inner wall of the through holes by chemical deposition, and the composite resin is injected into the through holes to obtain the glass substrate.

[0029] Preferably, the glass substrate is formed with through holes by laser drilling or photosensitive glass etching.

[0030] Preferably, the surface roughening treatment includes chemical etching.

[0031] Preferably, the chemical etching process uses a hydrofluoric acid-based etching solution, with the temperature controlled at 25°C to 40°C and the processing time at 3 to 8 minutes.

[0032] Preferably, the concentration of the hydrofluoric acid-based etching solution is 5% to 15%.

[0033] Preferably, an activation treatment is required before chemical deposition.

[0034] Preferably, the activation treatment involves using a palladium-based activation solution, a reaction temperature of 30–55°C, and a treatment time of 1–10 minutes. The purpose of the activation treatment is to form catalytic active centers on the glass substrate surface, promoting metal deposition on the glass surface.

[0035] Preferably, the concentration of the palladium-based activating solution is controlled between 60 ppm and 150 ppm.

[0036] Preferably, the composite resin is injected into the through hole using a vacuum pressure filling method.

[0037] Preferably, the processing conditions in the vacuum pressure filling method are as follows: the vacuum degree is controlled within a critical range below 50 Pa, followed by a three-step pressure increase, sequentially raising the pressure to 0.1 MPa, 0.5 MPa, and 0.8 MPa; after filling, a staged temperature curing program is adopted, sequentially curing at 80℃, 120℃, and 150℃ for 1 hour, 2 hours, and 4 hours respectively. Through the above steps, the resin can be progressively filled into the through-holes, allowing the composite resin to completely penetrate the dendritic structure.

[0038] Another aspect of the present invention provides applications of the glass substrate described above in high-frequency communication, power device, consumer electronics, or high-temperature environments. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the glass substrate provided in Embodiment 1 of the present invention; Figure 2 This is a cross-sectional SEM image of a glass substrate using the conventional copper paste filling method provided in Comparative Example 1 of this invention. Figure 3 This is a SEM image of the glass substrate provided in Embodiment 1 of the present invention. Detailed Implementation

[0040] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0041] Example 1 In this embodiment, the glass substrate is prepared according to the following method.

[0042] A glass substrate with a thermal expansion coefficient of 3.8 ppm / ℃ was used, and through holes were formed in the glass substrate by ultraviolet laser drilling.

[0043] A hydrofluoric acid-based etching solution (concentration 10%) was used, with the temperature controlled at 30℃ and the processing time 5 minutes, so that the surface roughness Ra of the hole wall reached 1.0μm~1.2μm, providing an adhesion basis for the subsequent chemical deposition of the annular conductive metal layer.

[0044] Using a palladium-based activating solution (concentration 100ppm), at a temperature of 40°C, and for a treatment time of 5 minutes, catalytic active centers were formed on the etched glass surface.

[0045] Subsequently, a first metal layer with a thickness of 5 μm (chemical copper deposition) was formed through chemical deposition. The chemical deposition adopted a stepped temperature control: first, deposition was carried out at 25°C for 10 minutes to form a uniform nucleation layer, then the temperature was increased to 35°C for 30 minutes to achieve rapid growth, and finally deposition was carried out at 40°C for 20 minutes to densify the copper layer. The pH value of the reaction solution was maintained at 12.8.

[0046] The composite resin was injected into the through-hole using a vacuum pressure filling method, with the vacuum level controlled within a critical range below 50 Pa. A three-step pressure increase was then employed, sequentially raising the pressure to 0.1 MPa, 0.5 MPa, and 0.8 MPa. After filling, a staged temperature-curing program was used, with curing occurring at 80℃, 120℃, and 150℃ for 1 hour, 2 hours, and 4 hours respectively. The composite resin formulation (by mass percentage) was: 70% bisphenol A epoxy resin, 25% silica (3 μm particle size), 12% methylhexahydrophthalic anhydride (anhydride curing agent), and 1.5% γ-aminopropyltriethoxysilane (silane coupling agent). The CTE of the cured composite resin was approximately 10 ppm / ℃.

[0047] A second metal layer (copper) with a thickness of 15 μm is deposited on the upper surface of the glass substrate by electroplating, and a third metal layer (copper) with a thickness of 15 μm is deposited on the lower surface. The thickness ratio is approximately 1:3:3.

[0048] Example 2 This embodiment prepares a glass substrate with reference to the formula and method provided in Embodiment 1. The difference from Embodiment 1 is that the surface roughness Ra of the hole wall is made to reach 1.5μm to 1.8μm when preparing the glass substrate in this embodiment. Apart from the above differences, the operation steps for preparing the glass substrate in this embodiment are strictly consistent with those in Embodiment 1.

[0049] Example 3 This embodiment prepares a glass substrate with reference to the formula and method provided in Embodiment 1. The difference from Embodiment 1 is that the thickness of the first metal layer is 8 μm when preparing the glass substrate in this embodiment. According to the thickness ratio, the ratio of the first metal layer to the second metal layer to the third metal layer is 1:2.5:2.5. Apart from the above differences, the operation steps for preparing the glass substrate in this embodiment are strictly consistent with those in Embodiment 1.

[0050] Example 4 This embodiment prepares a glass substrate with reference to the formula and method provided in Embodiment 1. The difference from Embodiment 1 is that the thickness of the first metal layer is 2 μm when preparing the glass substrate in this embodiment. According to the thickness ratio, the ratio of the first metal layer to the second metal layer to the third metal layer is 1:4:4. Apart from the above differences, the operation steps for preparing the glass substrate in this embodiment are strictly consistent with those in Embodiment 1.

[0051] Example 5 This embodiment prepares a glass substrate with reference to the formula and method provided in Embodiment 1. The difference from Embodiment 1 is that in this embodiment, the thicknesses of the first metal layer, the second metal layer, and the third metal layer are 5μm, 30μm, and 30μm, respectively, when preparing the glass substrate. Therefore, according to the thickness ratio, the ratio of the first metal layer to the second metal layer to the third metal layer is 1:6:6. Apart from the above differences, the operation steps for preparing the glass substrate in this embodiment are strictly consistent with those in Embodiment 1.

[0052] Example 6 This embodiment prepares a glass substrate using the formula and method provided in Example 1. The difference from Example 1 is that the composite resin used in this embodiment is formulated as follows: 60% cyanate ester resin, 35% silica (particle size 50nm), 4.5% anhydride curing agent, and 0.5% silane coupling agent (CTE approximately 9 ppm / ℃ after curing). Apart from the above differences, the operational steps for preparing the glass substrate in this embodiment are strictly consistent with those in Example 1.

[0053] Example 7 This embodiment prepares a glass substrate using the formulation and method provided in Example 1. The difference from Example 1 is that the composite resin used in this embodiment is formulated as follows: 55% phenolic resin, 20% aluminum nitride, 20% silica (particle size 2μm), 4% anhydride curing agent, and 1% silane coupling agent (introducing aluminum nitride to improve thermal conductivity; after curing, the CTE is approximately 12ppm / ℃). Apart from the above differences, the operational steps for preparing the glass substrate in this embodiment are strictly consistent with those in Example 1.

[0054] Example 8 This embodiment prepares a glass substrate with reference to the formulation and method provided in Example 1. The difference from Example 1 is that the formulation of the composite resin used in preparing the glass substrate in this embodiment is: 65% phenolic resin, 30% silica (particle size of 2μm), 4% acid anhydride curing agent, and 1% silane coupling agent (CTE of about 12ppm / ℃ after curing). Apart from the above differences, the operation steps for preparing the glass substrate in this embodiment are strictly consistent with those in Example 1.

[0055] Example 9 This embodiment prepares a glass substrate using the formulation and method provided in Example 1. The difference from Example 1 is that the composite resin used in this embodiment is formulated as follows: 50% polyimide resin, 45% boron nitride, 4% anhydride curing agent, and 1% silane coupling agent (polyimide is heat-resistant, and boron nitride is insulating and has high thermal conductivity, suitable for high-frequency applications) (CTE after curing is approximately 8 ppm / ℃). Apart from the above differences, the operational steps for preparing the glass substrate in this embodiment are strictly consistent with those in Example 1.

[0056] Example 10 This embodiment prepares a glass substrate using the formulation and method provided in Example 1. The difference from Example 1 is that the silica used in the composite resin formulation for preparing the glass substrate in this embodiment has a particle size of 0.1 μm (100 nm). (For epoxy resin systems, this particle size is in the nanometer range, making it prone to agglomeration, which may lead to a significant increase in viscosity and filling of pores.) Apart from the above differences, the operational steps for preparing the glass substrate in this embodiment are strictly consistent with those in Example 1.

[0057] Example 11 This embodiment prepares a glass substrate with reference to the formulation and method provided in Embodiment 6. The difference between this embodiment and Embodiment 6 is that the silica used in the composite resin formulation for preparing the glass substrate has a particle size of 15 μm. Apart from the above differences, the operation steps for preparing the glass substrate in this embodiment are strictly consistent with those in Embodiment 6.

[0058] Example 12 This embodiment prepares a glass substrate with reference to the formulation and method provided in Embodiment 7. The difference from Embodiment 7 is that the silica used in the composite resin formulation for preparing the glass substrate in this embodiment has a particle size of 0.05 μm (50 nm). Apart from the above differences, the operation steps for preparing the glass substrate in this embodiment are strictly consistent with those in Embodiment 7.

[0059] Comparative Example 1 This comparative example uses a copper paste filling method to prepare a glass substrate. The specific operation steps are as follows: (1) Provide a glass substrate with through holes; (2) Fill the through holes of the glass substrate with high solid content copper conductive paste by screen printing or vacuum filling. (3) Dry in air at 80°C for 30 minutes to remove most of the solvent; (4) Under nitrogen protection, sinter at 400°C for 60 minutes to form sintering necks between copper powder particles and achieve electrical connection; (5) The sintered substrate is ground and polished to remove excess copper paste and form a copper-filled through-hole structure.

[0060] Comparative Example 2 This comparative example prepares a glass substrate using the formula and method provided in Example 1. The difference between this comparative example and Example 1 is that the surface roughness Ra of the hole wall in this comparative example reaches 3μm to 3.3μm when preparing the glass substrate. Apart from the above differences, the operation steps for preparing the glass substrate in this comparative example are strictly consistent with those in Example 1.

[0061] Comparative Example 3 This comparative example prepares a glass substrate using the formula and method provided in Example 1. The difference between this comparative example and Example 1 is that the surface roughness Ra of the hole wall in this comparative example reaches 0.5 μm to 0.8 μm when preparing the glass substrate. Apart from the above differences, the operation steps for preparing the glass substrate in this comparative example are strictly consistent with those in Example 1.

[0062] Comparative Example 4 This comparative example prepares a glass substrate using the formulation and method provided in Example 1. The difference between this comparative example and Example 1 is that the coefficient of thermal expansion of the composite resin used in preparing the glass substrate is 20 ppm / ℃ to 25 ppm / ℃. Apart from the above differences, the operation steps for preparing the glass substrate in this comparative example are strictly consistent with those in Example 1.

[0063] Test case 1. Test Object The glass substrates prepared in Examples 1-12 and Comparative Examples 1-4.

[0064] 2. Testing Methods (1) Porosity: The Archimedes method was used for testing.

[0065] (2) Interface pull-out force: Tested according to ASTM D4541 standard.

[0066] (3) Cross-cut test: The test shall be conducted in accordance with ASTM D3359 standard.

[0067] (4) CAF failure rate: Tested according to IPC-TM-650 2.6.25 standard.

[0068] (5) Ion migration blocking: After completing 1000 hours of high temperature and high humidity testing, without applying bias voltage, the copper ion content in the condensate water or adsorbent material near the sample in the test chamber was quantitatively analyzed using ion chromatography (IC). At the same time, the tested samples were scanned by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) to observe and analyze the migration and distribution of copper elements near the resin / dendritic interface. Based on the amount of copper ion leakage and the diffusion width of copper elements at the interface, the blocking effect was rated as excellent (almost no detection / no diffusion), good (trace detection / diffusion <1μm), fair (obvious detection / diffusion 1-5μm), and poor (large detection / diffusion >5μm).

[0069] (6) Accelerated aging test: This test item is conducted according to the test conditions and standards shown in Table 1; if at least one item fails to meet the standard, the result is "fail"; if all items meet the standard, the result is "pass".

[0070] Table 1. Relevant Items for Accelerated Aging Test

[0071] 3. Test Results and Analysis The results obtained in this test are shown in Table 2. Comparing the test data of the examples and comparative examples, the "dendritic anchoring structure + matching resin CTE" scheme proposed in this application demonstrates significant technical advantages in terms of porosity, interfacial bonding force, cross-cut adhesion rating, and CAF reliability. The porosity of Examples 1 to 12 is generally controlled below 2.2%, with most examples below 1%. The interfacial pull-out force reaches above 17 MPa, with some examples even exceeding 28 MPa. Most cross-cut adhesion tests achieve a 5B or 4B rating. The CAF failure rate is essentially 0 or below 5% within 1000 hours, and the vast majority pass the accelerated aging test. These results fully verify the effectiveness and repeatability of this technical approach.

[0072] Figure 1This is used to visually demonstrate the core "dendritic anchoring" microstructure of the invention, which is the physical basis for achieving high bonding strength. Figure 2 As the most critical comparison with existing technologies, it directly exposes its inherent defects (high porosity, weak interface), and... Figure 1 This creates a strong visual contrast, highlighting the progressiveness of the invention. Figure 3 It provides direct evidence that the "dendritic anchoring + CTE matching" structure remains intact after experiencing extreme thermal stress, thus corroborating the conclusion of "accelerated aging: pass" in Table 2, and is the most powerful visual evidence to prove its long-term thermomechanical reliability.

[0073] Data from Examples 1-2 and Comparative Examples 2-3 show that controlling the roughness to above 1 μm, preferably within the range of 1-2 μm, helps to form a suitable dendritic structure, thereby achieving stable mechanical interlocking between the resin and the metal layer. Furthermore, although a dendritic structure was used in Comparative Example 4, the excessively high coefficient of thermal expansion of the composite resin resulted in significant thermal stress during temperature changes. The dendritic anchoring interface was subjected to repeated stretching and shearing, ultimately leading to an increased CAF failure rate and accelerated aging failure. This indicates that the dendritic structure alone is insufficient to cope with harsh thermal cycling conditions; the CTE of the composite resin must also be controlled within a range compatible with both the glass and metal layers to ensure the stability of the anchoring structure during long-term use.

[0074] Furthermore, the material composition of the composite resin and the particle size of its filler are equally crucial. Example 1 used bisphenol A type epoxy resin combined with silica; Example 6 used cyanate ester resin combined with silica; Example 7 used phenolic resin combined with aluminum nitride and silica; Example 8 used phenolic resin combined with silica; and Example 9 used polyimide resin combined with boron nitride. These examples all exhibited good performance at their respective preferred filler particle sizes, demonstrating the good versatility of the resin and filler combinations in this application. In contrast, although Examples 10 to 12 used the same resin type as Examples 1, 6, and 7, their porosity increased, interfacial pull-out force decreased, and CAF suppression effect weakened due to the filler particle size deviating from the preferred range (e.g., in Example 10, excessively fine nano-sized silica easily agglomerates in the epoxy system, leading to uneven filling). This, in turn, confirms that selecting an appropriate filler particle size for different resin systems is an important prerequisite for ensuring dense filling and interfacial reliability.

[0075] The thickness ratio between the metal layers also affects the stress distribution and reliability of the overall structure. In Example 5, the thickness ratio of the first metal layer to the upper and lower surface metal layers exceeded the preferred range defined in the claims (i.e., the surface metal layer was too thick). Test results showed that its porosity increased to 1.5%, the interface pull-out force decreased to 18.3 MPa, the cross-cut adhesion level decreased to 3B, the CAF failure rate was 0.1%, and accelerated aging failed. This indicates that when the surface metal layer is relatively too thick, it may introduce additional thermal stress during thermal cycling, thereby weakening the stability of the dendrite anchoring structure. Reasonably controlling the thickness relationship of the three layers is beneficial to optimizing current distribution and heat dissipation, and improving the electrical reliability and thermomechanical life of the overall structure.

[0076] Furthermore, the single deposition temperature in existing technologies has limitations in balancing the uniformity, deposition rate, and density of the deposited layer. The deposition method provided in this application employs a stepped heating strategy to improve this issue: During the low-temperature nucleation stage (e.g., 25-30°C), uniform and fine copper nuclei can be formed on the roughened glass surface, which is beneficial for improving the coverage of subsequent deposition, especially suitable for the bottom and sidewalls of high aspect ratio vias. Entering the medium-temperature growth stage (e.g., 30-35°C), the deposition rate can be further increased, which helps to quickly build the main thickness of the metal layer, while the columnar crystal growth is guided by the already formed uniform nuclei. During the high-temperature densification stage (e.g., 35-40°C), atomic mobility is enhanced, and the grain arrangement inside the copper layer tends to be more compact, which helps to reduce defects and improve conductivity and mechanical strength.

[0077] Table 2. Test Results

[0078] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A glass substrate, characterized in that, The glass substrate includes at least one through hole and a composite resin filling the through hole, and a first metal layer is further included between the through hole and the composite resin; Wherein, the roughness Ra of the first metal layer is ≥1μm; The coefficient of thermal expansion of the composite resin is 8ppm / ℃ to 15ppm / ℃.

2. The glass substrate as described in claim 1, characterized in that, The roughness of the first metal layer is 1μm≤Ra≤2μm.

3. The glass substrate as described in claim 1, characterized in that, The thickness of the first metal layer is 2μm to 8μm.

4. The glass substrate as described in claim 1, characterized in that, The diameter of the through hole is 10μm~250μm, and the depth-to-width ratio is 1~15:

1.

5. The glass substrate as described in claim 1, characterized in that, The composite resin includes a resin material, which includes at least one of cyanate ester resin, phenolic resin, bisphenol A type epoxy resin, and polyimide resin; and / or, the composite resin includes an inorganic filler, which includes at least one of aluminum nitride, boron nitride, and silicon dioxide; and / or, the composite resin includes a silane coupling agent.

6. The glass substrate as described in claim 5, characterized in that, The composite resin comprises a resin material and an inorganic filler, wherein the resin material and the inorganic filler satisfy at least one of the following conditions: (a) The resin material includes cyanate ester resin, and the inorganic filler includes silica; (b) The resin material includes phenolic resin, and the inorganic filler includes aluminum nitride and silicon dioxide; (c) The resin material comprises bisphenol A type epoxy resin, and the inorganic filler comprises silica; (d) The resin material includes polyimide resin, and the inorganic filler includes boron nitride.

7. The glass substrate as described in claim 6, characterized in that: In (a), the particle size of the silica used is 20 nm to 100 nm; And / or, in (b), the particle size of the silica used is 0.5 μm to 5 μm; And / or, in (c), the particle size of the silica used is 1 μm to 10 μm; And / or, in (d), the particle size of the silica used is 0.1 μm to 1 μm.

8. The glass substrate as described in claim 1, characterized in that: The first metal layer covers the inner wall of the through hole and the area around the opening of the through hole; And / or, the upper surface of the glass substrate is covered with a second metal layer, and the lower surface of the glass substrate is covered with a third metal layer.

9. The glass substrate as described in claim 8, characterized in that: Based on the thickness ratio, the ratio of the first metal layer to the second metal layer to the third metal layer is 1:2~5:2~5.

10. The application of the glass substrate as described in any one of claims 1 to 9 in the fields of high-frequency communication, power devices, consumer electronics, or high-temperature environments.

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