A manufacturing method for reducing the breakage rate of TGV products

Abstract

The application discloses a manufacturing method for reducing the breakage rate of TGV products, which comprises the following steps: forming a modified area on a glass substrate by laser induction using a femtosecond laser, and then forming a through hole on the modified area by wet etching using an etching solution; chamfering the through hole opening by the femtosecond laser, and performing layer-by-layer chamfering by vertically irradiating the laser to the glass substrate and spirally expanding the laser outward along the edge of the through hole, wherein the laser focus depth and the laser energy are changed from inside to outside layer by layer, a smooth transition conical surface is formed, and right-angle stress concentration is eliminated; removing a micro-crack layer generated by laser processing on the surface of the glass substrate by using a hydrofluoric acid solution, and then performing O2 plasma treatment; depositing Al2O3 as a transition layer by atomic layer deposition; sputtering Ti and TiN in sequence as adhesion layers by sputtering, and then sputtering Cu as a conductive layer; performing gradual electroplating and annealing, pre-plating a 2-3 mu m Cu thin layer on the conductive layer, and then performing one-time annealing, and then electroplating Cu to a target thickness, and then performing one-time annealing again; removing excess Cu by chemical mechanical polishing (CMP), and finally performing surface RDL to obtain a final TGV product.

Description

Technical Field

[0001] This invention relates to a manufacturing method for reducing the breakage rate of TGV products. Background Technology

[0002] TGV (Through Glass Via) technology is a key process in advanced packaging and semiconductor manufacturing, and is widely used in 3DIC packaging, MEMS sensors, RF devices, microdisplays and other fields.

[0003] Due to the inherent brittleness, high hardness, and low fracture toughness of glass, TGV products are prone to breakage during manufacturing, resulting in issues such as shattering, microcracks, and edge chipping (e.g., Figure 1 This can lead to a decrease in yield and an increase in costs, and may even affect the reliability of end products, severely restricting the development of related industries. Summary of the Invention

[0004] The present invention provides a manufacturing method for reducing the breakage rate of TGV products in order to solve the problems existing in the prior art.

[0005] The technical solutions adopted in this invention are as follows:

[0006] A manufacturing method for reducing the breakage rate of TGV products includes the following steps:

[0007] S1: After laser-induced formation of modified areas on the glass substrate using a femtosecond laser, wet etching is performed on the modified areas using an etching solution to form through holes.

[0008] S2: Femtosecond laser is used to chamfer the opening of the through hole. The laser is directed perpendicularly to the glass substrate and spirals outward along the edge of the through hole to perform chamfering layer by layer. The laser focusing depth and laser energy are changed layer by layer from the inside to the outside to form a smooth transition conical surface and eliminate right angle stress concentration.

[0009] S3: Use hydrofluoric acid to treat the surface of the glass substrate to remove the microcrack layer generated by laser processing, and then perform O2 plasma treatment;

[0010] S4: Al2O3 is deposited as a transition layer via atomic layer deposition;

[0011] S5: Ti and TiN are sputtered sequentially as an adhesion layer, and then Cu is sputtered as a conductive layer.

[0012] S6: Progressive electroplating and annealing are adopted. First, a 2-3μm Cu thin layer is pre-plated on the conductive layer and then annealed once. Then, Cu is electroplated to the target thickness and annealed again.

[0013] S7: Excess Cu is removed by chemical mechanical polishing (CMP), and the final surface is RDL to obtain the final TGV product.

[0014] Furthermore, in S1, the operating parameters of the femtosecond laser are: wavelength of 343-1030nm, pulse energy of 0.1-5uJ, repetition frequency of 10-100KHZ, and scanning speed of 100-1000mm / s.

[0015] Furthermore, in S1, the etching solution is composed of the following components in volume concentrations: 5-10% HF, 5-10% NH4F and 0.1%-0.5% surfactant, with the balance being water;

[0016] The etching process conditions are: etching at a temperature of 20-40°C for 20-40 minutes, combined with 80KHZ ultrasonic waves.

[0017] Furthermore, the surfactant is Triton X-100.

[0018] Furthermore, in S2, during the chamfering process, the operating parameters of the femtosecond laser are: 343-1030nm, pulse energy 0.1-5uJ, repetition frequency 10-100KHZ, scanning speed 100-1000mm / s, expanding outward from the edge of the hole, pitch 1-5um, changing the focusing depth layer by layer, with energy decreasing by 10%-20% per layer to reduce stress concentration.

[0019] Furthermore, in S3, a 1-3% hydrofluoric acid solution is used to treat the substrate for 10-30 seconds to remove the microcrack layer generated by laser processing, followed by O2 plasma treatment to remove organic matter and activate the hydroxyl groups on the glass substrate surface.

[0020] Furthermore, in S4, an atomic layer of Al2O3 is deposited at a depth of 10-20 nm as a transition layer.

[0021] Furthermore, in S5, Ti 50nm is sputtered first using a low-temperature sputtering method at 60-100℃, then TiN 20nm is sputtered as an adhesion layer, and then Cu 200-500nm is sputtered as a conductive layer.

[0022] Furthermore, in S6, a progressive electroplating and annealing process is adopted. Specifically, after pre-plating a 2-3 μm Cu thin layer, the plated material is annealed at 200°C for 30 min in a N2 atmosphere with a heating rate of 1-3°C / min. Then, after electroplating to the target thickness, the plated material is annealed again at 200°C for 1 h in a N2 atmosphere with a heating rate of <3°C / min.

[0023] The present invention has the following beneficial effects:

[0024] 1. By optimizing the process flow, including chamfering design, plasma activation, nano-coating protection, and progressive electroplating and annealing, stress concentration in the glass is effectively reduced, thereby lowering the breakage rate of TGV products during manufacturing due to glass brittleness, high hardness, and low fracture toughness, and significantly improving product yield and reliability.

[0025] 2. O2 plasma treatment of the glass substrate surface can remove organic contaminants and activate the hydroxyl groups on the surface, enhance the adhesion between the seed layer and the glass substrate, ensure the firm adhesion of the subsequent metal layer, and improve the stability and durability of the product during use.

[0026] 3. Atomic layer deposition of Al2O3 serves as a transition layer, buffering the thermal expansion coefficient (CTE) mismatch between metal Cu and glass, reducing the risk of interfacial delamination or cracking caused by differences in thermal expansion, improving the bonding strength and stability of the interface, and extending the service life of the product.

[0027] 4. By sputtering Ti and TiN at low temperature as an adhesion layer, and then sputtering Cu as a conductive layer, a high-quality seed layer is formed, which provides a good conductive foundation for subsequent electroplating, ensures uniform deposition of Cu in the through-hole and good conductivity, and improves the electrical connection quality of TGV products.

[0028] 5. The chamfering process eliminates the sharp edges of the through-hole opening, reduces stress concentration in the glass, improves the metallization coverage, and enhances the mechanical strength of the product, enabling it to withstand greater mechanical stress during subsequent processing and use without easily being damaged. Attached Figure Description

[0029] Figure 1 This diagram illustrates the tendency for TGV products to break during the manufacturing process.

[0030] Figure 2 The TGV product obtained by using the manufacturing method of the present invention. Detailed Implementation

[0031] The invention will now be further described with reference to the accompanying drawings.

[0032] This invention discloses a manufacturing method for reducing the breakage rate of TGV products, comprising the following steps:

[0033] S1: In this embodiment, Corning Pyrex® 7740 glass substrate is selected. The glass substrate is laser-induced using a femtosecond laser with a wavelength of 343-1030nm, a pulse energy of 0.1-5uJ, a repetition frequency of 10-100KHZ, and a scanning speed of 100-1000mm / s. After the modified area is formed by laser induction, the via is formed by wet etching with HF-based etchant.

[0034] HF-based etching solutions are composed of a mixture of the following components at the following volume concentrations:

[0035] 5-10% HF, 5-10% NH4F and 0.1%-0.5% surfactant (Triton X-100), balance water.

[0036] The etching process conditions are as follows: etching at a temperature of 20-40°C for 20-40 minutes, while simultaneously swishing up and down, and using 80KHZ ultrasonic waves to assist in forming through holes.

[0037] S2: Chamfering treatment;

[0038] Femtosecond lasers are used to chamfer the openings of through-holes. The laser is directed perpendicularly to the glass substrate and spirals outward along the edge of the through-hole. The laser focusing depth and laser energy are changed layer by layer from the inside to the outside to form a smooth transition conical surface (angle 30-45°), eliminating right-angle stress concentration. 。

[0039] The laser process parameters for chamfering are as follows:

[0040] The laser has a wavelength of 343-1030nm, a pulse energy of 0.1-5uJ, a repetition frequency of 10-100KHZ, and a scanning speed of 100-1000mm / s.

[0041] Expand outwards from the edge of the hole, with a pitch of 1-5µm, and change the focusing depth layer by layer, reducing the energy by 10%-20% with each layer to reduce stress concentration.

[0042] S3: Micro-engraving and plasma activation;

[0043] Treat with low-concentration HF (1-3%) for 10-30 seconds to remove the microcrack layer generated by laser processing, and then perform O2 plasma treatment (100W, 5min) to remove organic matter and activate hydroxyl groups (-OH) on the glass surface, thereby improving the adhesion between the seed layer and the glass.

[0044] S4: Nano-coating protection;

[0045] Atomic layer deposition (ALD) uses Al2O3 (10~20nm) as a transition layer to buffer the subsequent mismatch of thermal expansion coefficient (CTE) between the metal and glass. The deposition temperature is 80-150℃, the reaction chamber pressure is 0.5-2 Torr, and the number of cycles is 100-200.

[0046] S5: Low-stress deposition of the seed layer;

[0047] A low-temperature (60-100℃) sputtering method was used to first sputter Ti (50nm) + TiN (20nm) as an adhesion layer, and then sputter Cu (200-500nm) as a conductive layer.

[0048] S6: Progressive electroplating and annealing;

[0049] After pre-plating a 2-3 μm Cu thin layer, annealing is performed at 200°C for 30 min in a N2 atmosphere (heating rate of 1-3°C / min). Then, after plating to the target thickness, annealing is performed again at 200°C for 1 h in a N2 atmosphere, with a heating rate of <3°C / min.

[0050] Low-stress acidic copper sulfate plating solution is used during electroplating. The formula is as follows:

[0051] CuSO4·5H2O (80g / L) + H2SO4 (50g / L) + PEG-8000 (200ppm, inhibitor) + SPS (50ppm, leveling agent) and sodium saccharin (100ppm, stress reliever), at a temperature of 25±1℃.

[0052] S7: Flattening;

[0053] Chemical mechanical polishing (CMP) removes excess Cu. The polishing slurry formulation is: Al2O3 abrasive + H2O2 (pH=10). The polishing pad is a soft pad (SUBAIV) to reduce copper erosion. The process conditions are: pressure 3–5 psi, speed 100–120 rpm, and time 90–180 s.

[0054] S8: Surface RDL;

[0055] TGV products are obtained using conventional processes such as metallization, photolithography, etching, resist removal, and passivation.

[0056] Figure 2 The accompanying drawings show the TGV product obtained by using the manufacturing method of the present invention. As can be seen from the drawings, the method of the present invention significantly overcomes the fragmentation phenomenon existing in the prior art.

[0057] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A manufacturing method for reducing the breakage rate of TGV products, characterized in that: Includes the following steps: S1: After laser-induced formation of modified areas on the glass substrate using a femtosecond laser, wet etching is performed on the modified areas using an etching solution to form through holes. S2: Femtosecond laser is used to chamfer the opening of the through hole. The laser is directed perpendicularly to the glass substrate and spirals outward along the edge of the through hole to perform chamfering layer by layer. The laser focusing depth and laser energy are changed layer by layer from the inside to the outside to form a smooth transition conical surface and eliminate right angle stress concentration. S3: Use hydrofluoric acid to treat the surface of the glass substrate to remove the microcrack layer generated by laser processing, and then perform O2 plasma treatment; S4: Al2O3 is deposited as a transition layer via atomic layer deposition; S5: Ti and TiN are sputtered sequentially as an adhesion layer, and then Cu is sputtered as a conductive layer. S6: Progressive electroplating and annealing are adopted. First, a 2-3μm Cu thin layer is pre-plated on the conductive layer and then annealed once. Then, Cu is electroplated to the target thickness and annealed again. S7: Excess Cu is removed by chemical mechanical polishing (CMP), and the final surface is RDL to obtain the final TGV product.

2. The manufacturing method for reducing the breakage rate of TGV products as described in claim 1, characterized in that: In S1, the operating parameters of the femtosecond laser are: wavelength 343-1030nm, pulse energy 0.1-5uJ, repetition frequency 10-100KHZ, and scanning speed 100-1000mm / s.

3. The manufacturing method for reducing the breakage rate of TGV products as described in claim 1, characterized in that: In S1, the etching solution is a mixture of the following components in volume concentrations: 5-10% HF, 5-10% NH4F and 0.1%-0.5% surfactant, with the balance being water; The etching process conditions are: etching at a temperature of 20-40°C for 20-40 minutes, combined with 80KHZ ultrasonic waves.

4. The manufacturing method for reducing the breakage rate of TGV products as described in claim 3, characterized in that: The surfactant is Triton X-100.

5. The manufacturing method for reducing the breakage rate of TGV products as described in claim 1, characterized in that: In S2, during chamfering, the operating parameters of the femtosecond laser are: 343-1030nm, pulse energy 0.1-5uJ, repetition frequency 10-100KHZ, scanning speed 100-1000mm / s, expanding outward from the edge of the hole, pitch 1-5um, changing the focusing depth layer by layer, and reducing the energy by 10%-20% with each layer to reduce stress concentration.

6. The manufacturing method for reducing the breakage rate of TGV products as described in claim 1, characterized in that: In S3, a 1-3% hydrofluoric acid solution is used to treat the substrate for 10-30 seconds to remove the microcrack layer generated by laser processing. Then, O2 plasma treatment is performed to remove organic matter and activate the hydroxyl groups on the surface of the glass substrate.

7. The manufacturing method for reducing the breakage rate of TGV products as described in claim 1, characterized in that: In S4, 10-20 nm of Al2O3 is deposited as a transition layer.

8. The manufacturing method for reducing the breakage rate of TGV products as described in claim 1, characterized in that: In S5, Ti 50nm is sputtered first using a low-temperature sputtering method at 60-100℃, then TiN 20nm is sputtered as an adhesion layer, and finally Cu 200-500nm is sputtered as a conductive layer.

9. The manufacturing method for reducing the breakage rate of TGV products as described in claim 1, characterized in that: S6 employs a progressive electroplating and annealing process, specifically: after pre-plating a 2-3 μm Cu thin layer, it is annealed at 200°C for 30 minutes in an N2 atmosphere with a heating rate of 1-3°C / min. Then, after electroplating to the target thickness, it is annealed again at 200°C for 1 hour in an N2 atmosphere with a heating rate of <3°C / min.

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