A method for realizing TGV high-conductivity copper-clad by using a magnetic filtering vacuum arc metal film

Abstract

The application discloses a method for realizing TGV high-conductivity copper-clad by using a magnetic filtering vacuum arc metal film, and specifically comprises the following steps: S1, ultrasonic cleaning is performed on a glass through-hole substrate; S2, sub-etching cleaning treatment and activation of a substrate surface are performed on the glass through-hole substrate under a vacuum environment; S3, a Ti film layer is deposited on the glass through-hole substrate after the treatment in S2 by using a magnetic filtering vacuum cathode arc method; and S4, a Cu film layer is deposited on the Ti film layer under a low vacuum environment. By using the method provided by the application, a Ti undercoat layer is first deposited, the problem of poor adhesion between Cu and a glass substrate is solved, then copper-clad deposition is performed, in addition, the glass substrate can be conductive after Ti plating, so that the bias voltage can be increased, the energy of Cu ions entering the hole is larger, the thickness of the film plated on the hole wall is improved, the adhesion is stronger, and the conductivity is improved.

Description

Technical Field

[0001] This invention belongs to the field of microelectronic packaging technology, and specifically relates to a method for achieving high conductivity copper plating in TGV using a magnetically filtered vacuum arc metal film. Background Technology

[0002] Through-Glass Via (TGV) is an emerging microelectronic packaging technology that enables high-density electrical interconnects by forming through-holes in a glass substrate and depositing conductive films on their inner walls. Compared to traditional silicon-based through-holes (TSV) and organic substrates, TGV glass offers low loss, high transparency, and excellent thermal stability, and is therefore widely used in 5G communications, optoelectronic packaging, MEMS sensors, and other fields.

[0003] Despite the promising prospects of TGV glass through-hole coating technology, several technical challenges remain: 1. Uniformity of coating on the inner wall of through holes: Through holes with high aspect ratios (5:1 to 10:1) are prone to problems such as metal accumulation at the hole opening and insufficient filling at the bottom of the hole; 2. Difficulty in seed layer deposition: Glass is an insulator, so the key is how to form a high-quality conductive seed layer on the inner wall of the via. 3. Stress control within the hole: The different coefficients of thermal expansion between metal and glass may lead to warping or cracking; 4. Coating adhesion: The glass surface is smooth, and the adhesion of metal is weak, so the surface treatment process needs to be optimized. Summary of the Invention

[0004] To address the above problems, this invention provides a method for achieving high-conductivity copper plating in TGV using a magnetically filtered vacuum arc metal film.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for achieving high-conductivity copper plating in TGV using a magnetically filtered vacuum arc metal film specifically includes the following steps: S1. Perform ultrasonic cleaning on the glass through-hole substrate; S2. Under vacuum conditions, perform sub-glass cleaning and activate the substrate surface of the glass through-hole substrate; S3. A Ti film is deposited on the glass through-hole substrate treated in S2 using magnetically filtered vacuum cathode arc technology; S4. Deposit a Cu film on the Ti film under vacuum.

[0006] Furthermore, S1 specifically includes the following steps: S11. Place the glass through-hole substrate in a pure water alkaline solution with a mass fraction of 1%~8% and perform ultrasonic cleaning for 5~20 minutes, with an ultrasonic power of 50~150W. S12. Place the glass through-hole substrate in pure water and perform ultrasonic cleaning twice, each time for 5-20 minutes, with an ultrasonic power of 50-150W. S13. Place the glass through-hole substrate in alcohol or acetone and perform ultrasonic cleaning for 5 minutes, with an ultrasonic power of 50~150W. S14. Bake and dry the glass through-hole substrate at 65~90℃ for 15~40min.

[0007] Furthermore, S2 specifically involves evacuating the coating chamber to a background vacuum of 0.5E-3Pa to 4E-3Pa, using oxygen and argon plasma to perform argon ion cleaning and oxygen activation on the surface of the glass through-hole substrate, with an applied bias power of 100 to 300W, a gas pressure of 0.1 to 0.3Pa, and a process time of 30 to 60 minutes.

[0008] Furthermore, S3 specifically involves: in a vacuum environment, using metallic Ti as a target material, applying a negative bias voltage to the glass through-hole substrate, with the negative bias voltage range being 50~500V, the duty cycle being 2%-75%, the metallic Ti current being 90~200A, and the deposition time being 1000~2000s.

[0009] Furthermore, the thickness of the Ti film is 50~500 nm.

[0010] Furthermore, in S4, the Cu film layer is composed of multiple layers of magnetically filtered vacuum cathode arc Cu film layer and multiple layers of magnetron sputtered Cu film layer arranged alternately from the Ti film layer upwards.

[0011] Furthermore, S4 specifically includes the following steps: S41. Vacuuming, using metallic Cu as the target material, applying a negative bias voltage on the glass through-hole substrate, the negative bias voltage range is 50-1000V, the duty cycle is 2%-75%, the metallic Cu current is 90~200A, the deposition time is 1800~3000, and the thickness of the single-layer magnetic filter vacuum cathode arc Cu coating is 20~500nm. S42. Inert gas is introduced into the cavity to a pressure of 0.2~0.6Pa. Metallic Cu is used as the target material and sputtered at a medium frequency or DC sputtering power of 1~5kW for a sputtering time of 1500~5000s. The thickness of the single-layer magnetron sputtered Cu film is 20~500nm. S43. Repeat steps S41 and S42 until the total thickness of the Cu film is 1~3 μm.

[0012] Furthermore, each layer of the magnetically filtered vacuum cathode arc method Cu film has the same thickness, and each layer of the magnetron sputtering Cu film has the same thickness. The ratio of the thickness of the magnetron sputtering Cu film to the thickness of the magnetically filtered vacuum cathode arc method Cu film is in the range of 1:4 to 2:1.

[0013] The present invention describes a method for achieving high-conductivity copper plating in TGV using a magnetically filtered vacuum arc metal film. First, Ti is deposited as the underlayer to solve the problem of poor adhesion between Cu and the glass substrate. Then, copper plating is performed. In addition, the glass substrate becomes conductive after Ti plating, which can increase the bias voltage, thereby increasing the energy of Cu ions entering the holes, increasing the thickness of the hole wall coating, strengthening the adhesion, and improving the conductivity. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the longitudinal section of the copper-clad glass through-hole substrate obtained in Embodiment 1 of the present invention.

[0015] Among them, 1-glass through-hole substrate, 2-Ti film layer, 3-magnetically filtered vacuum cathode arc method Cu film layer, 4-magnetron sputtering Cu film layer. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0017] A method for achieving high-conductivity copper plating in TGV using a magnetically filtered vacuum arc metal film specifically includes the following steps: S1. Ultrasonic cleaning of the glass through-hole substrate: The glass through-hole substrate is placed in a pure water alkaline solution with a mass fraction of 1%~8% and ultrasonically cleaned for 5~20 minutes with an ultrasonic power of 50~150W; then the glass through-hole substrate is placed in pure water and ultrasonically cleaned twice, each time for 5~20 minutes with an ultrasonic power of 50~150W; next, the glass through-hole substrate is placed in alcohol or acetone and ultrasonically cleaned for 5 minutes each time with an ultrasonic power of 50~150W; finally, the glass through-hole substrate is baked and dried at 65~90℃ for 15~40 minutes.

[0018] S2. Evacuate the furnace cavity to a background vacuum of 0.5E-3Pa~4E-3Pa, and use oxygen and argon plasma to perform sub-glass cleaning treatment and oxygen activation of the substrate surface on the glass through-hole substrate. The power is 100~300W, the gas pressure is 0.1~0.3Pa, and the process time is 30~60 minutes.

[0019] S3. Using magnetically filtered vacuum cathode arc technology, in a vacuum and inert gas environment, with metallic Ti as the target material, a negative bias voltage is applied to the glass through-hole substrate. The negative bias voltage range is 50~500V, the duty cycle is 2%~25%, the metallic Ti current is 90~200A, the deposition time is 1000~2000s, and the thickness of the Ti film is 100~200nm.

[0020] S4. In a vacuum environment, a Cu film is deposited on the Ti film layer, specifically: S41. Vacuum is drawn, and a negative bias voltage is applied to the glass through-hole substrate using metallic Cu as the target material. The negative bias voltage range is 50~500V, the duty cycle is 2%~25%, the metallic Cu current is 90~200A, and the deposition time is 1800~3000s. S42. Inert gas is introduced into the cavity until the pressure is 0.2~0.4Pa. Metal Cu is used as the target material and sputtering is performed at a radio frequency sputtering power of 4~6kW for a sputtering time of 1500~5000s. S43. Repeat steps S41 and S42.

[0021] In step S4, the Cu film layer consists of two alternating layers of magnetically filtered vacuum cathode arc method Cu film layer and two layers of magnetron sputtered Cu film layer arranged upwards from the Ti film layer. Each magnetically filtered vacuum cathode arc method Cu film layer has the same thickness, and each magnetron sputtered Cu film layer has the same thickness. The thickness ratio of the magnetron sputtered Cu film layer to the magnetically filtered vacuum cathode arc method Cu film layer ranges from 1:4 to 2:1; the thickness of the magnetically filtered vacuum cathode arc method Cu film layer is 30 to 100 nm. Example

[0022] Experimental substrate: a quartz glass sheet with a thickness of 2mm and a length*width of 50*50mm.

[0023] The copper plating process using the above methods is the same, including chemical cleaning and ion cleaning activation. The only difference is that sample A uses a medium-frequency magnetron sputtering source (MF-SPT) to complete a 1μm Cu film on a glass slide, while sample B uses a magnetically filtered cathode arc source (FCVA) to complete a 1μm Cu film on a glass substrate.

[0024] Using a cross-cut cross-cut tester, sample A only achieved a grade of 0B, while sample B reached a grade of 2B. Example

[0025] Experimental substrate: a quartz glass sheet with a thickness of 2mm and a length*width of 50*50mm.

[0026] The copper plating process described above involves the same chemical cleaning and ion cleaning activation techniques; the only difference lies in... Sample C was prepared using magnetically filtered cathode arc source (FCVA) technology. A 0.05µm FCVA-Ti film was deposited on a glass substrate, followed by a 1.0µm FCVA-Cu film, for a total film thickness of 1.05µm. Sample D was prepared using magnetically filtered cathode arc source (FCVA) technology. A 0.1µm FCVA-Ti film was deposited on a glass substrate, followed by a 1.0µm FCVA-Cu film, for a total film thickness of 1.1µm. Sample E was prepared using magnetically filtered cathode arc source (FCVA) technology. A 0.15µm FCVA-Ti film was deposited on a glass substrate, followed by a 1.0µm FCVA-Cu film, for a total film thickness of 1.1µm. Sample F was prepared using magnetically filtered cathode arc source (FCVA) technology. A 0.2µm FCVA-Ti film was deposited on a glass substrate, followed by a 1.0µm FCVA-Cu film, for a total film thickness of 1.1µm. Sample G was prepared using magnetically filtered cathode arc source (FCVA) technology. A 0.4 μm FCVA-Ti coating was deposited on a glass substrate, followed by a 1.0 μm FCVA-Cu coating, for a total coating thickness of 1.1 μm.

[0027] The above samples were subjected to a 100-cut test in sequence, and the specific steps are as follows: (1) Grid marking: First, use a special grid cutter to draw multiple parallel lines on the coating surface; then, draw another set of lines perpendicular to the first set of lines to form a grid similar to "*chessboard (hundred grids)**". (2) Clean up the debris. Use a brush or air to clean up the debris generated by the marking. (3) Apply tape: Apply the standard test tape to the marked area and press it firmly; (4) Quickly tear off the tape; (5) Observe the results and check whether the coating has been removed from the grid area.

[0028] Tests showed that sample C achieved a 3B level; sample D achieved a 3B to 4B level; sample E achieved a 4B to 5B level; and samples F and G achieved a 5B level, meaning that the adhesion of the film layer improved sequentially from sample C to sample F. Example

[0029] Experimental substrate: a quartz glass sheet with a thickness of 200um and a length*width of 50*50mm, with densely distributed through holes of 35um in diameter. The back of the TGV glass sheet is tightly attached to a quartz glass plate without holes.

[0030] The copper plating process, including chemical cleaning and ion cleaning activation, is the same as described above. The only difference is that magnetically filtered cathode arc source (FCVA) technology is used to deposit a 0.2µm FCVA-Ti film on the glass substrate, followed by a 1.0µm FCVA-Cu film to obtain sample H, with a total coating thickness of 1.2µm. Sample I was prepared by using magnetically filtered cathode arc source (FCVA) technology to form a 0.2 μm FCVA-Ti base layer on a glass substrate, followed by a 1.0 μm Cu coating on the glass substrate using a medium frequency magnetron sputtering source (MF-SPT).

[0031] The height of the titanium-copper dots on the glass substrate was measured using a profilometer. The film thickness of sample H ranged from 38 to 63 nm, with an average of 48 nm; the film thickness of sample I ranged from 142 to 270 nm, with an average of 216 nm. A thicker film resulted in better perforation performance.

[0032] The TGV vias of samples H and I were tested. Although the thickness of the via opening in sample H was thicker than the sidewall film thickness at deeper locations, there was no risk of sealing. However, the copper plating thickness on the sidewall of the via opening in sample I continued to increase relative to sample H, which posed a risk of sealing. Example

[0033] Experimental substrate: a quartz glass sheet with a thickness of 200um and a length*width of 50*50mm, with densely distributed through holes of 35um in diameter. The back of the TGV glass sheet is tightly attached to a quartz glass plate without holes.

[0034] The copper plating process, including chemical cleaning and ion cleaning activation, is identical, and a 0.2µm FCVA-Ti underlayer coating is achieved on the glass substrate using magnetically filtered cathode arc source (FCVA) technology. The only difference is... Using a mid-frequency magnetron sputtering source (MF-SPT) at 50 nm and a magnetically filtered cathode arc source (FCVA) at 100 nm, a 1.05 μm Cu film was deposited on a glass substrate in 7 cycles to obtain sample J. Using a medium-frequency magnetron sputtering source (MF-SPT) at 100 nm and a magnetically filtered cathode arc source (FCVA) at 100 nm, a 1.0 μm Cu film was deposited on a glass substrate in 5 cycles to obtain sample K. Using a medium-frequency magnetron sputtering source (MF-SPT) at 100 nm and a magnetically filtered cathode arc source (FCVA) at 50 nm, a 1.05 μm Cu film was deposited on a glass substrate in 7 cycles to obtain sample L. Using a mid-frequency magnetron sputtering source (MF-SPT) at 200 nm and a magnetically filtered cathode arc source (FCVA) at 50 nm, a 1.0 μm Cu film was deposited on a glass substrate in four cycles to obtain sample M.

[0035] The height of the titanium-copper dots on the glass substrate was measured using a profilometer. The film thickness of sample J was approximately 198 nm; sample L was approximately 163 nm; and sample M was approximately 139 nm. A thicker film thickness resulted in better perforation performance.

[0036] After double-sided coating and electroplating thickening, the through-holes were fully plated with copper. Observation of the TGV through-hole cross section revealed that samples M had voids in their through-holes, while samples J, K, and L did not have voids.

[0037] It should be noted that: 1) SPT has a much faster deposition rate than FCVA, approximately 8 to 10 times faster. The testing equipment can deposit 100nm of copper using SPT in just 240 to 300 seconds, with the rotating stand rotating 5 to 8 times. Further thinning requires consideration of the poor circumferential uniformity caused by the fewer rotations. 2) The FCVA coating time is very slow. The test equipment takes about 3000~3500 seconds to coat 100nm of copper with FCVA. The filter bend is already very hot, so it is not advisable to increase the coating thickness in a single round.

[0038] Those skilled in the art should understand that the above description is merely a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for realizing TGV high-conductivity copper-clad by using a magnetic filtering vacuum arc metal film, characterized in that, Specifically, the following steps are included: S1. Perform ultrasonic cleaning on the glass through-hole substrate; S2. Under vacuum conditions, perform sub-glass cleaning and activate the substrate surface of the glass through-hole substrate; S3. A Ti film is deposited on the glass through-hole substrate treated in S2 using magnetically filtered vacuum cathode arc technology; S4. Deposit a Cu film on the Ti film under vacuum.

2. The method for realizing TGV high-conductivity copper-clad by using magnetic filtering vacuum arc metal film according to claim 1, characterized in that, S1 specifically includes the following steps: S11. Place the glass through-hole substrate in a pure water alkaline solution with a mass fraction of 1%~8% and perform ultrasonic cleaning for 5~20 minutes, with an ultrasonic power of 50~150W. S12. Place the glass through-hole substrate in pure water and perform ultrasonic cleaning twice, each time for 5-20 minutes, with an ultrasonic power of 50-150W. S13. Place the glass through-hole substrate in alcohol or acetone and perform ultrasonic cleaning for 5 minutes, with an ultrasonic power of 50~150W. S14. Bake and dry the glass through-hole substrate at 65~90℃ for 15~40min.

3. The method of claim 1, wherein the TGV high-conductivity copper-clad is realized by a magnetic filtering vacuum arc metal film, and the method is characterized in that, Specifically, S2 involves evacuating the coating chamber to a background vacuum of 0.5E-3Pa to 4E-3Pa, using oxygen and argon plasma to perform argon ion cleaning and oxygen activation on the surface of the glass through-hole substrate, with an applied bias power of 100 to 300W, a gas pressure of 0.1 to 0.3Pa, and a process time of 30 to 60 minutes.

4. The method of claim 1, wherein the TGV high-conductivity copper-clad is realized by a magnetic filtering vacuum arc metal film, and the method is characterized in that, Specifically, S3 involves applying a negative bias voltage to the glass via substrate in a vacuum environment, using metallic Ti as the target material. The negative bias voltage range is 50~500V, the duty cycle is 2%-75%, the metallic Ti current is 90~200A, and the deposition time is 1000~2000s.

5. The method for realizing TGV high-conductivity copper-clad by using magnetic filtering vacuum arc metal film according to claim 4, characterized in that, The thickness of the Ti film is 50~500 nm.

6. The method of claim 1, wherein the TGV high-conductivity copper-clad is achieved by using a magnetic filtering vacuum arc metal film. In S4, the Cu film layer is composed of multiple layers of magnetically filtered vacuum cathode arc Cu film layer and multiple layers of magnetron sputtered Cu film layer arranged alternately from the Ti film layer upwards.

7. The method for realizing TGV high-conductivity copper-clad by using magnetic filtering vacuum arc metal film according to claim 6, characterized in that, S4 specifically includes the following steps: S41. Vacuuming, using metallic Cu as the target material, applying a negative bias voltage on the glass through-hole substrate, the negative bias voltage range is 50-1000V, the duty cycle is 2%-75%, the metallic Cu current is 90~200A, the deposition time is 1800~3000, and the thickness of the single-layer magnetic filter vacuum cathode arc Cu coating is 20~500nm. S42. Inert gas is introduced into the cavity to a pressure of 0.2~0.6Pa. Metallic Cu is used as the target material and sputtered at a medium frequency or DC sputtering power of 1~5kW for a sputtering time of 1500~5000s. The thickness of the single-layer magnetron sputtered Cu film is 20~500nm. S43. Repeat steps S41 and S42 until the total thickness of the Cu film is 1~3 μm.

8. The method for achieving high conductivity copper plating in TGV using a magnetically filtered vacuum arc metal film according to claim 7, characterized in that, The thickness of each layer of the magnetically filtered vacuum cathode arc method Cu film is the same, and the thickness of each layer of the magnetron sputtering Cu film is the same. The ratio of the thickness of the magnetron sputtering Cu film to the thickness of the magnetically filtered vacuum cathode arc method Cu film is in the range of 1:4 to 2:1.

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