Method for manufacturing glass direct copper clad circuit

Abstract

The application provides a manufacturing method of glass direct copper clad circuit, relates to the technical field of microelectronic circuit manufacturing, and comprises the following steps: S01, copper foil surface planarization: the copper foil is adhered to a UV photosensitive adhesive film, and the surface of the adhered copper foil is ground; after the surface of the copper foil is ground to reach a target roughness, the copper foil is cleaned and dried; S02, laminated static pressure: a glass substrate, the UV photosensitive adhesive film with the adhered copper foil and a carrier plate are sequentially laminated and fixed, vacuum is drawn and sealed, static pressure is applied to the formed sealed body, and a structure to be welded is obtained; and S03, laser selective welding: an ultrashort pulse laser and a short pulse are combined, and multiple compound scans are performed by using an energy gradient, so that the problem that an interface gap cannot be effectively reduced and the interface is easy to be ablated when a laser is used for welding to manufacture a glass copper clad circuit is solved, and the interface fusion capacity between the copper foil and the glass is improved.

Description

Technical Field

[0001] This invention relates to the field of microelectronic circuit manufacturing technology, and specifically to a method for manufacturing glass-copper-clad circuits. Background Technology

[0002] Glass materials are mainly bonded by ionic and covalent bonds, exhibiting very stable electronic coordination. Due to the unique physicochemical properties of glass materials, circuit boards based on glass have broad application prospects in optical communication, radio frequency, microwave, microelectromechanical systems, microfluidic devices and three-dimensional integration.

[0003] Because of its smooth surface, glass has low adhesion to copper, making it prone to metal layer peeling and curling when used to fabricate circuit boards. Its chemical inertness also presents significant practical challenges in creating high-performance metal circuits on glass surfaces. Traditional sputtering-etching techniques typically result in weak bonding between the metal circuits and the glass. Screen printing and micropen direct writing techniques usually involve first screen printing or writing the circuit pattern onto the glass surface, followed by high-temperature or low-temperature sintering to obtain the conductive circuitry. However, high-temperature sintering can easily deform the glass, while low-temperature sintering reduces conductivity and bonding strength.

[0004] For glass materials, laser welding can be used to join glass and metal. A focused laser beam penetrates the glass to heat the glass-metal interface, melting the material near the interface, and finally solidifying the melt to achieve the weld. However, the high temperature during welding and the mismatch in thermal expansion between the glass and metal can easily lead to microcracks or even glass breakage. Furthermore, the welding process has stringent requirements for interface quality and gap. Patent CN112846499A proposes an ultrafast laser welding method and system for glass-metal encapsulation, using an ultrashort pulse laser to limit the welding thermal effect and designing a movable fixture to control the interface gap through fixture pressure. Patent CN115673549A proposes a glass-metal laser composite welding method, utilizing the thermal and impact effects of continuous lasers and the high processing precision and nonlinear absorption phenomenon of ultrafast lasers to overcome the difficulty of processing the base material contact surface in ultrafast laser welding, achieving the welding of quartz glass and zirconium metal. However, for glass-clad copper circuits, directly welding the glass and copper foil using laser welding requires large-area welding. Controlling the gap between the two using fixtures easily leads to uneven stress distribution, resulting in inconsistent weld interfaces. Furthermore, applying pressure simultaneously with the laser results in high stress at the bonding interface, and the mismatch in thermal expansion between the copper foil and glass easily causes weld cracks. Because the copper foil is relatively thin, the increase in thickness caused by heating with long-pulse lasers is small, resulting in weak ability to close interface gaps and making it impossible to simultaneously fabricate the circuit pattern during the welding process.

[0005] Therefore, how to better reduce the interface gap during the fabrication of glass-clad copper circuits and improve the interface fusion capability between glass and metal is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a method for manufacturing glass-copper-clad circuits, which solves the problems of ineffective reduction of interface gaps and easy interface ablation when using laser welding to manufacture glass-copper-clad circuits, and improves the interface fusion strength between glass and copper foil.

[0007] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: This invention discloses a method for manufacturing a glass-to-copper-clad circuit, comprising the following steps: S01. Copper foil surface planarization: The copper foil is flattened and adhered to the UV photosensitive adhesive film, and the surface of the copper foil after adhesion is ground. After the copper foil surface is ground to the target roughness, the copper foil is cleaned and dried. S02, Lamination and Static Pressing: The glass substrate, the UV photosensitive adhesive film with copper foil attached, and the carrier plate are sequentially laminated and fixed, and then vacuum sealed. The sealed body is subjected to static pressing to obtain the structure to be welded. S03, Selective Laser Welding: Employing a combination of ultrashort pulse lasers and short pulses, multiple composite scans are performed using energy gradients.

[0008] Furthermore, in step S03, the laser selective welding specifically includes the following steps in sequence: S03-1, ultrashort pulse laser welding, wherein the ultrashort pulse laser pulse is less than 10 picoseconds; S03-2, short-pulse laser welding, wherein the short-pulse laser pulse is at the nanosecond level; S03-3, low-energy laser welding, using short-pulse laser welding with progressively decreasing laser energy.

[0009] Furthermore, the target surface roughness Ra of the copper foil is less than 0.1 μm.

[0010] Furthermore, in step S02, after the glass substrate and copper foil are laminated and evacuated, the temperature during static pressure of the laminate is 50-85℃ and the pressure is 20-60MPa.

[0011] Furthermore, before proceeding to step S01, circuit patterning is first performed, specifically including: placing copper foil on a porous adsorption platform, and cutting out circuit pattern channels and forming circuit patterns using laser cutting.

[0012] In another embodiment, after step S03, circuit patterning is performed, specifically including the following steps: After removing the welded structure, the UV photosensitive adhesive film is irradiated with ultraviolet light and then directly peeled off. Circuit pattern channels are then cut out on the copper foil to form the circuit pattern.

[0013] Furthermore, the width of the circuit pattern outline is 10-150 μm.

[0014] Furthermore, the thickness of the copper foil is 10-150 μm.

[0015] (III) Beneficial Effects This invention provides a method for manufacturing glass-to-copper-clad circuits. Compared with the prior art, it has the following advantages: This solution effectively reduces the interfacial gap by using isostatic pressing and employs a combination of ultrashort pulse laser and short pulse laser for laser processing. The ultrashort pulse laser induces micro-connection between the glass and the copper foil. Based on this, the laser surface ablation is effectively suppressed through the thermal effect of the short pulse, resulting in fewer laser-induced defects and increased fusion thickness at the welding interface. Furthermore, a lower laser power is used to eliminate stress at the welding interface, ultimately obtaining a reliable welding interface. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a graphical representation of copper foil. Figure 2 A schematic diagram of the electrostatic lamination process for manufacturing glass-to-copper-clad circuits; Figure 3 A schematic diagram showing the laser welding process; Figure 4 Top view diagram of laser welding selection; Figure 5 This is a graphical schematic diagram of a laser cutting circuit. Figure 6 A schematic diagram of a direct copper-clad glass circuit; Figure 7 Product illustration for glass-to-copper-clad circuit manufacturing.

[0018] Figure label: 1. Glass substrate; 2. Copper foil; 21. Copper foil circuit; 22. Channel; 3. UV photosensitive adhesive film; 4. Carrier plate; 5. Adhesive tape; 6. Laser beam. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] This application provides a method for manufacturing glass-copper-clad circuits, which solves the problem that the interface gap cannot be effectively reduced when manufacturing glass-copper-clad circuits, and improves the ability to bridge the interface gap between copper foil and glass.

[0021] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0022] like Figures 1-7 As shown, a method for manufacturing a glass-to-copper-clad circuit includes the following steps: S01. Copper foil surface planarization: Copper foil 2 is flatly adhered to UV photosensitive adhesive film 3, and the surface of copper foil 2 after adhesion is ground. After the surface of copper foil 2 is ground to the target roughness, copper foil 2 is cleaned and dried. Specifically, the copper foil thickness is 10-150 μm, and the surface roughness Ra of the copper foil 2 is less than 0.1 μm; Copper foil 2 was placed on a porous adsorption platform and adhered to UV photosensitive adhesive film 3 by a film laminator. The surface of the copper foil was mechanically ground, cleaned and dried. The roughness Ra of the bonding surface between the copper foil 2 and the glass substrate 1 was measured to be less than 0.1 μm using a confocal microscope. S02, Lamination and Static Pressing: Glass substrate 1, UV photosensitive adhesive film 3 with copper foil 2 attached and carrier plate 4 are sequentially laminated and fixed, and then vacuum sealed. The formed sealed body is subjected to static pressing to obtain the structure to be welded. Specifically, the glass substrate 1, the UV photosensitive adhesive film 3 with copper foil 2 adhered to it, and the carrier plate 4 are stacked in sequence and fixed with tape 5. They are then placed in a sealing bag and vacuumed. The vacuum-sealed sealing bag is then sealed to form a sealed body. The sealed body is placed in a hot isostatic pressing chamber for static pressing. The sealing bag is then removed to obtain the structure to be welded. It should be noted that after the glass substrate 1 and copper foil 2 are laminated and vacuumed, the temperature during the static pressing of the laminate is 50-85℃ and the pressure is 20-60MPa. S03. Selective Laser Welding: This method combines ultrashort pulse lasers with short pulses, using energy gradients for multiple composite scans. Specifically, it includes the following steps: Step S03-1, ultrashort pulse laser welding; In step S03-1, the ultrashort pulse laser pulse is less than 10 picoseconds. The glass substrate 1 absorbs energy through nonlinear effects and fuses with the gap at the interface of the copper foil. There is no thermal ablation at the interface, and the two achieve optical contact. Step S03-2, short-pulse laser welding; Step S03-3, low-energy laser welding; In steps S03-2 and S03-3, the short-pulse laser pulse is preferably in the nanosecond range, which effectively suppresses laser surface ablation, reduces laser-induced defects, increases the fusion thickness of the welding interface, and further uses lower laser energy to alleviate and release the welding stress at the interface. Specifically, laser beam 6 is used for surface welding. First, the copper foil 2 and glass substrate 1 are scanned multiple times with an ultra-short pulse laser. Then, the copper foil 2 and glass substrate 1 are scanned with a short pulse laser. The laser parameters in the laser parameters are gradually reduced, and the copper foil 2 and glass substrate 1 are scanned again with the changed short pulse laser. The same short pulse laser with the same laser parameters is used to scan multiple times. S04, Circuit pattern localization: Remove the fixing of the solder structure, use ultraviolet light to irradiate the UV photosensitive adhesive film 3 and then directly peel off the adhesive film, cut out the circuit pattern channel 22 on the copper foil 2 and form the circuit pattern. Specifically, after welding, copper foil 2 connected to glass substrate 1 can be obtained on glass substrate 1. The fixing tape 5 is removed, releasing the fixation of glass substrate 1, UV photosensitive adhesive film 3 (attached to copper foil 2), and carrier plate 4. UV photosensitive adhesive film 3 is irradiated with ultraviolet light for 30-300 seconds. Since the UV film has partial adhesiveness, it is directly peeled off. Circuit pattern channels 22 are cut out using laser cutting to selectively weld the edge contour, forming the circuit pattern. The contour width is 10-150μm. The unwelded copper foil 2 is removed, resulting in a circuit board with glass substrate 1 as the base. Figure 6 As shown; In another embodiment, a method for manufacturing a glass-to-copper-clad circuit can directly use copper foil that has been patterned by means of etching, stamping, laser cutting, etc., and then directly obtain the glass-to-copper-clad circuit by following steps S01-S03.

[0023] In summary, this solution effectively reduces the interfacial gap by using isostatic pressing and employs a combination of ultrashort pulse laser and short pulse laser for laser processing. The ultrashort pulse laser induces micro-connection between the glass and the copper foil. Based on this, the laser surface ablation is effectively suppressed through the thermal effect of the short pulse, resulting in fewer laser-induced defects and increased fusion thickness at the welding interface. Furthermore, the use of a lower laser power eliminates stress at the welding interface, ultimately leading to a reliable welding interface. It should be noted that the final reliable weld interface is determined by measuring the bonding strength between the glass and copper cladding through shear stress. Specifically, copper foil is bonded to glass on both sides, with the laser bonding surface being a circle with a diameter of 2.5 mm. Using a chip tensile shear tester, referring to GJB-548B-2005 Method 2019.2, a pushing force is applied parallel to the bonding surface to peel off the two glass substrates, obtaining the shear strength of the laser bond, thereby determining the reliability of the weld interface.

[0024] The following is a detailed description of the fabrication of glass-clad copper circuits, using examples 1 and 2 as examples: Example 1: A method for manufacturing a glass-to-copper-clad circuit, comprising the following steps: Step S01: A 50μm thick copper foil 2 is attached to a UV photosensitive adhesive film 3 using a laminator. Then, the surface of the copper foil 2 is mechanically ground, the surface is cleaned, and after natural drying, the surface roughness Ra of the copper foil is measured to be no higher than 0.1μm using a confocal microscope. Step S02: The glass substrate 1, the UV photosensitive adhesive film 3 with copper foil 2 attached, and the carrier plate 4 are stacked and fixed at the edges with tape 5. Figure 2 As shown; after fixing, place it in a sealing bag and evacuate it for 60 seconds with a vacuum pressure of 0.1 MPa, then seal the sealing bag; place the sealed body in a hot isostatic pressing chamber and press it statically for 15 minutes at a temperature of 60℃ and a pressure of 35 MPa; remove the sealing bag to obtain the structure to be welded.

[0025] Step S03, as follows Figure 3 As shown, laser beam 6 is used to scan glass substrate 1 for surface welding; during welding: copper foil 2 and glass substrate 1 are selectively welded using an ultrashort pulse laser, and the scan is repeated once; The laser parameters are as follows: wavelength 535nm, pulse width 800fs, and flat-top spot size 50μm. 50μm, average power 3.5W, repetition frequency 100kHz; spot overlap rate 50%;

[0026] Next, short-pulse lasers were used to selectively weld copper foil 2 to glass substrate 1, and the scan was repeated 5 times. The laser parameters are as follows: wavelength 355nm, pulse width 100ns, Gaussian spot size φ10μm, average power 1.2W, repetition frequency 40kHz; spot overlap rate 50%. Then, copper foil 2 and glass substrate 1 were selectively welded using a short-pulse laser, and the scan was repeated 5 times. The laser parameters are as follows: wavelength 355nm, pulse width 100ns, Gaussian spot size φ10μm, average power 0.8W, repetition frequency 50kHz; spot overlap rate 50%. Finally, short-pulse laser was used to selectively weld copper foil 2 to glass substrate 1, and the scan was repeated 5 times. The laser parameters are as follows: wavelength 355nm, pulse width 100ns, Gaussian spot size φ10μm, average power 0.5W, repetition frequency 50kHz; spot overlap rate 50%. Step S04: After welding, a copper foil circuit 21 connected to the glass substrate 1 can be obtained on the glass substrate 1. Remove the fixing tape 5, irradiate the UV photosensitive adhesive film 3 with ultraviolet light, and remove the film after irradiation for 300 seconds. With the copper foil 2 facing up, form three channels 22 with a contour width of 35μm by laser cutting or other methods, and repeat the scanning once to complete the patterned copper foil 2. Remove the unwelded copper foil 2 to obtain the glass copper foil circuit board. The laser cutting parameters are as follows: wavelength 355nm, pulse width 100ns, Gaussian spot size φ10μm, average power 5W, repetition frequency 32kHz; spot overlap rate 50%. Example 2: A method for manufacturing a glass-to-copper-clad circuit, comprising the following steps: Step S01, as follows Figure 1 As shown, a copper foil 2 with a thickness of 150μm is placed on a porous adsorption platform, and five circuit pattern channels 22 with a contour width of 45μm are cut out by laser, and the scan is repeated 20 times. The laser cutting parameters are as follows: wavelength 355nm, pulse width 100ns, Gaussian spot size 10μm, average power 5W, repetition frequency 32kHz; spot overlap rate 50%. The copper foil 2 with etched grooves 22 is attached to the UV photosensitive adhesive film 3 using a film attaching machine. Then, the surface of the copper foil 2 is mechanically ground, the surface is cleaned with water, and after natural drying, the surface roughness Ra of the copper foil 2 is measured to be no higher than 0.1 μm using a confocal microscope. Step S02, as follows Figure 2 As shown, a glass substrate 1, a UV photosensitive adhesive film 3 with copper foil 2 attached, and a carrier plate 4 are stacked and fixed at the edges with tape 5. After fixing, the substrate is placed in a sealing bag and vacuumed for 60 seconds at a vacuum pressure of 0.1 MPa. Then, the substrate is sealed with a sealing bag. The sealed substrate is placed in a hot isostatic pressing chamber and statically pressed for 15 minutes at a temperature of 85°C and a pressure of 50 MPa. The sealing bag is then removed to obtain the structure to be welded.

[0027] Step S03, as follows Figure 3 As shown, laser beam 6 is used to scan glass substrate 1 for surface welding; during welding: copper foil 2 and glass substrate 1 are selectively welded using an ultrashort pulse laser, and the scan is repeated once; The laser parameters are as follows: wavelength 1030nm, pulse width 800fs, Bessel beam spot size φ3μm, average power 8W, repetition frequency 100kHz; and spot spacing on the welding surface 3μm. Next, short-pulse lasers were used to selectively weld copper foil 2 to glass substrate 1, and the scan was repeated 5 times. The laser parameters are as follows: wavelength 535nm, pulse width 100ns, Gaussian spot size φ15μm, average power 2W, repetition frequency 80kHz; spot overlap rate 50%. Then, short-pulse lasers were used to selectively weld copper foil 2 to glass substrate 1, and the scan was repeated 5 times. The laser parameters are as follows: wavelength 535nm, pulse width 100ns, Gaussian spot size φ15μm, average power 1W, repetition frequency 80kHz; spot overlap rate 50%.

[0028] Finally, copper foil 2 and glass substrate 1 were selectively welded using a short-pulse laser, and the scan was repeated 5 times. The laser parameters are as follows: wavelength 535nm, pulse width 100ns, Gaussian spot size φ15μm, average power 0.5W, repetition frequency 80kHz; spot overlap rate 50%. Step S04: After soldering is completed, a copper foil circuit 21 connected to the glass substrate 1 can be obtained on the glass substrate 1, such as... Figure 5 As shown, after completing the patterned copper foil 2, remove the fixing tape, irradiate the UV photosensitive adhesive film 3 with ultraviolet light for 800 seconds, then remove the adhesive film and the unbonded copper foil 2 to obtain the desired result. Figure 6 Glass copper foil circuit board.

[0029] In summary, it should be noted that the circuit patterning can be completed after the composite laser welding is completed (Example 1) or before the copper foil 2 is adhered to the UV photosensitive adhesive film 3 (Example 2). During the circuit fabrication process, the above two patterning methods are used, which both take into account the circuit patterning and improve the overall process continuity.

[0030] In summary, compared with existing technologies, it has the following beneficial effects: 1. This invention directly uses copper foil 2 and glass substrate 1 to realize the metallization circuit of glass, and while being suitable for large-size processing, it achieves better economic results.

[0031] 2. This invention effectively balances the graphical fabrication of circuits and improves process continuity.

[0032] 3. This invention uses a layered static pressure method to remove gas, which makes it easy to operate, has a high yield, and low welding internal stress, enabling the finished products to achieve better performance.

[0033] 4. This invention uses a composite laser welding method, which overcomes the problem that the interface is relatively thin and the strength and high temperature resistance are relatively poor when using only ultra-short pulse welding. At the same time, the nanosecond ultraviolet laser is used to thicken the welding interface, suppress interface ablation, and enhance the consistency of the welding surface.

[0034] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0035] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for manufacturing a glass-to-copper-clad circuit, characterized in that, Includes the following steps: S01. Copper foil surface planarization: The copper foil is flattened and adhered to the UV photosensitive adhesive film, and the surface of the copper foil after adhesion is ground. After the copper foil surface is ground to the target roughness, the copper foil is cleaned and dried. S02, Lamination and Static Pressing: The glass substrate, the UV photosensitive adhesive film with copper foil attached, and the carrier plate are sequentially laminated and fixed, and then vacuum sealed. The sealed body is subjected to static pressing to obtain the structure to be welded. S03, Selective Laser Welding: Employing a combination of ultrashort pulse lasers and short pulses, multiple composite scans are performed using energy gradients.

2. The manufacturing method of a glass-to-copper-clad circuit as described in claim 1, characterized in that, In step S03, laser selective welding specifically includes the following steps in sequence: S03-1, ultrashort pulse laser welding, wherein the ultrashort pulse laser pulse is less than 10 picoseconds; S03-2, short-pulse laser welding, wherein the short-pulse laser pulse is at the nanosecond level; S03-3, low-energy laser welding, using short-pulse laser welding with progressively decreasing laser energy.

3. The manufacturing method of a glass-to-copper-clad circuit as described in claim 1, characterized in that, The target surface roughness Ra of the copper foil is less than 0.1 μm.

4. The manufacturing method of a glass-to-copper-clad circuit as described in claim 1, characterized in that, In step S02, after the glass substrate and copper foil are laminated and evacuated, the temperature during static pressure lamination is 50-85℃ and the pressure is 20-60MPa.

5. The manufacturing method of a glass-to-copper-clad circuit as described in claim 1, characterized in that, Before proceeding to step S01, circuit patterning is first performed, which includes placing copper foil on a porous adsorption platform and cutting out circuit pattern channels and forming circuit patterns using laser cutting.

6. The manufacturing method of a glass-to-copper-clad circuit as described in claim 1, characterized in that, After step S03, the circuit diagram is then created, which includes the following steps: After removing the welded structure, the UV photosensitive adhesive film is irradiated with ultraviolet light and then directly peeled off. Circuit pattern channels are then cut out on the copper foil to form the circuit pattern.

7. A method for manufacturing a glass-to-copper-clad circuit as described in claim 5 or 6, characterized in that, The width of the circuit pattern outline is 10-150μm.

8. The manufacturing method of a glass-to-copper-clad circuit as described in claim 1, characterized in that, The thickness of the copper foil is 10-150 μm.

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