Dam substrate and preparation method thereof

Abstract

The embodiment of the invention provides a dam substrate and a preparation method thereof. The preparation method of the dam substrate comprises the steps that at least one through hole penetrating through the thickness direction of a substrate body is formed in the substrate body; respectively forming a first photoresist pattern and a second photoresist pattern on the upper surface and the lower surface of the substrate body around the through hole; performing metal filling on the through hole, the first photoresist pattern and the second photoresist pattern by adopting an electroplating process to form a first metal bonding pad and a second metal bonding pad; evaporating a first self-propagating film on a chip connection area and a box dam connection area on the upper surface of the first metal bonding pad; and welding a box dam frame material on the first self-propagating film in the box dam connecting area, and evaporating a second self-propagating film on the upper surface of the box dam frame material for connecting a packaging plate. According to the dam substrate and the preparation method thereof disclosed by the embodiment of the invention, rapid welding of the dam can be realized, the process flow is simplified, the process cost is reduced, and the problem of substrate warping caused by electroplating is solved.

Description

Technical Field

[0001] The embodiments of the present disclosure belong to the technical field of substrate packaging, and particularly relate to a dam substrate and a preparation method thereof. Background Art

[0002] Lamp beads used in UV LED light curing, disinfection and sterilization require the substrate to provide airtight packaging, so a dam needs to be set on the substrate, and the holes formed by the dam and the substrate are filled with glue or inert gas to achieve good airtightness and increase the service life of the product. In the related technology, the dam on the substrate is realized through an electroplating process, the process control process is complex, and the overall production rhythm is slow. In addition, the subsequent packaging process of the chip and the sealing quartz glass will cause two thermal shock damages to the strength of the substrate, shortening the service life. Summary of the invention

[0003] The embodiments of the present disclosure aim to solve at least one of the technical problems existing in the prior art and provide a dam substrate and a method for preparing the same.

[0004] In one aspect, an embodiment of the present disclosure provides a method for preparing a dam substrate, the method for preparing the dam substrate comprising:

[0005] Providing a substrate body;

[0006] At least one through hole is formed on the substrate body and extends through the substrate body in a thickness direction;

[0007] forming a first photoresist pattern and a second photoresist pattern around the through hole on the upper and lower surfaces of the substrate body respectively;

[0008] The through hole, the first photoresist pattern and the second photoresist pattern are filled with metal by an electroplating process to form a first metal pad and a second metal pad respectively located on the upper and lower surfaces of the substrate body, and two ends of the filling metal in the through hole are respectively connected to the first metal pad and the second metal pad;

[0009] A first self-propagating film is evaporated on the chip connection area and the dam connection area on the upper surface of the first metal pad; a dam frame material is welded on the first self-propagating film in the dam connection area, and a second self-propagating film is evaporated on the upper surface of the dam frame material to connect the packaging board.

[0010] Optionally, before forming the first photoresist pattern and the second photoresist pattern around the through hole respectively, a metal seed layer is formed on the upper and lower surfaces of the substrate body and the inner wall of the through hole.

[0011] Optionally, the metal seed layer is a titanium layer or a copper layer, and the thickness of the metal seed layer is in the range of 0.5um-3um.

[0012] Optionally, the film systems of the first self-propagating film and the second self-propagating film both include at least one of Ti—Al, Al—Ni, Ti—Ni, Ni—Si, Nb—Si, Al—CuOx, and Al—Pt.

[0013] Optionally, the step of evaporating a first self-propagating thin film on a chip connection region and a dam connection region on the upper surface of the first metal pad comprises:

[0014] forming a third photoresist pattern in a chip connection region and a dam connection region on the upper surface of the first metal pad;

[0015] The third photoresist pattern is evaporated by an evaporation process to form the first self-propagating film located in the chip connection area and the dam connection area, and the thickness of the first self-propagating film ranges from 0.5um to 5um.

[0016] Optionally, welding the dam frame material on the first self-propagating film in the dam connection area comprises:

[0017] Processing the copper foil into the shape of the dam frame material by laser or etching, wherein the thickness of the copper foil is 0.2 mm to 0.6 mm;

[0018] The dam frame material is welded to the dam connection area by any one of laser, heating and ignition.

[0019] Optionally, after welding the dam frame material to the dam connection area, the preparation method further comprises:

[0020] The surfaces of the dam frame material, the first metal pad, the second metal pad and the substrate body are cleaned and plated with a surface finishing layer.

[0021] Optionally, the finishing layer is one of a silver layer, a nickel-gold layer and a nickel-palladium-gold layer, and the thickness of the finishing layer ranges from 0.5um to 5um.

[0022] Optionally, the substrate body is one of an aluminum nitride ceramic substrate, an aluminum oxide ceramic substrate and a diamond substrate, the aperture size of the through hole is 50um-300um, and the thickness of the second self-propagating film is in the range of 0.5um-5um.

[0023] On the other hand, an embodiment of the present disclosure provides a dam substrate, which is obtained by the preparation method described above, and the dam substrate comprises:

[0024] A substrate body, wherein the substrate body is provided with at least one through hole penetrating the substrate body in a thickness direction;

[0025] A first metal pad, wherein the first metal pad is located on the upper surface of the substrate body;

[0026] A second metal pad, the second metal pad is located on the lower surface of the substrate body, and the second metal pad is connected to the first metal pad through a filling metal in the through hole;

[0027] A first self-propagating film, wherein the first self-propagating film is located in a chip connection area and a dam connection area on the upper surface of the first metal pad; wherein a dam frame material is welded to the first self-propagating film in the dam connection area;

[0028] A second self-propagating film is located on the upper surface of the dam frame material and is used for connecting the packaging board.

[0029] The dam substrate and preparation method of the disclosed embodiment can realize the rapid welding of the dam, simplify the process flow, reduce the process cost, and solve the substrate warping problem caused by electroplating. The application of self-propagating film in chip welding or airtight packaging interface can reduce packaging cost and improve packaging efficiency and yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic flow chart of a method for preparing a dam substrate according to an embodiment of the present disclosure;

[0031] Figure 2 The figure is a schematic structural diagram of a dam substrate according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the technical solution of the present disclosure, the present disclosure is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0033] like Figure 1 As shown, a method for preparing a dam substrate includes S110, providing a substrate body. Specifically, the substrate body can be one of an aluminum nitride ceramic substrate, an aluminum oxide ceramic substrate and a diamond substrate.

[0034] S120, forming at least one through hole penetrating the thickness direction of the substrate body. Specifically, in this step, laser drilling can be performed on the selected substrate body, and the through hole punched through the upper and lower surfaces of the substrate body to form a through hole, and the aperture size of the through hole can be 50um-300um, such as 58um, 65um, 80um, 150um, 230um, 280um, etc.

[0035] After the laser drilling is completed, an alkaline solution / HF (hydrofluoric acid) is used to clean the laser processed substrate body to remove the slag generated by the laser processing. The alkaline solution can be NaOH or KOH.

[0036] After cleaning, a metal seed layer is formed by sputtering on the upper and lower surfaces of the substrate body and the inner wall of the through hole by magnetron sputtering. The metal seed layer can be a metal layer such as a titanium layer or a copper layer, and the thickness of the metal seed layer ranges from 0.5um to 3um, such as 0.6um, 0.66um, 1.5um, 2um, etc.

[0037] S130, forming a first photoresist pattern and a second photoresist pattern around the through hole on the upper and lower surfaces of the substrate body respectively.

[0038] Specifically, in this step, photoresist is used in conjunction with exposure and development technology to form a first photoresist pattern and a second photoresist pattern around each through hole on the upper and lower surfaces of the substrate body, respectively, so as to transfer the required pad pattern to the upper and lower surfaces of the substrate body.

[0039] S140, using an electroplating process to fill the through hole, the first photoresist pattern and the second photoresist pattern with metal to form a first metal pad and a second metal pad respectively located on the upper and lower surfaces of the substrate body, and the two ends of the filling metal in the through hole are respectively connected to the first metal pad and the second metal pad.

[0040] Specifically, in this step, the through hole, the first photoresist pattern and the second photoresist pattern are filled with metal, such as copper, by using an electroplating process. Finally, a first metal pad is formed on the upper surface of the substrate body, and a second metal pad is formed on the lower surface of the substrate body. The first metal pad and the second metal pad are connected correspondingly through the filling metal in the through hole. After the electroplating is completed, the electroplated first metal pad and the second metal pad are leveled to improve the flatness of the pad surface, and then the film is stripped and etched to obtain the pad circuit on the surface of the substrate body.

[0041] S150, vapor-depositing a first self-propagating film on the chip connection area and the dam connection area on the upper surface of the first metal pad, welding a dam frame material on the first self-propagating film in the dam connection area, and vapor-depositing a second self-propagating film on the upper surface of the dam frame material to connect to a packaging board.

[0042] Specifically, in this step, first, a third photoresist pattern is formed in the chip connection area and the dam connection area on the upper surface of the first metal pad, and the third photoresist pattern is evaporated by an evaporation process to form the first self-propagating film located in the chip connection area and the dam connection area. Secondly, the copper foil is processed into the shape of the dam frame material by laser or etching, wherein the thickness of the copper foil is 0.2mm-0.6mm, such as 0.35mm, 0.46mm, 0.55mm, etc. The dam frame material is welded to the first self-propagating film in the dam connection area by any of laser, heating and ignition.

[0043] The film system of the first self-propagating film includes at least one of Ti-Al, Al-Ni, Ti-Ni, Ni-Si, Nb-Si, Al-CuOx, and Al-Pt, and the thickness of the first self-propagating film ranges from 0.5um to 5um, such as 0.6um, 0.85um, 1.5um, 3um, 4.5um, etc. The first self-propagating film is used to weld the dam frame material, replacing the traditional electroplating process to connect the dam and the substrate, simplifying the process control steps, reducing the production cost, and being able to solve the problem of stress warping in the thick copper electroplating process.

[0044] Afterwards, the surface of the dam frame material, the first metal pad, the second metal pad and the substrate body are cleaned and a surface finishing layer is plated. The finishing layer can be one of a silver layer, a nickel-gold layer and a nickel-palladium-gold layer, and the thickness of the finishing layer ranges from 0.5um to 5um. After the surface finishing layer is plated, a second self-propagating film is evaporated on the upper surface of the dam frame material using photoresist exposure and development technology. The film system of the second self-propagating film includes at least one of Ti-Al, Al-Ni, Ti-Ni, Ni-Si, Nb-Si, Al-CuOx, and Al-Pt, and the thickness of the second self-propagating film ranges from 0.5um to 5um, such as 0.6um, 0.85um, 1.5um, 3um, 4.5um, etc. The entire preparation of the dam substrate is completed.

[0045] As an example, when the prepared dam substrate is used, such as in UV airtight packaging or any electronic packaging device that requires a dam, the chip is connected to the first self-propagating film in the chip connection area, and the packaging plate, such as quartz glass, is connected to the second self-propagating film on the upper surface of the dam frame material. The chip and quartz glass packaging are carried out simultaneously, which reduces the thermal shock damage to the substrate, reduces the packaging cost of the lamp bead device, and improves the packaging efficiency and yield.

[0046] The method for preparing the dam substrate of the embodiment of the present disclosure can realize the rapid welding of the dam, simplify the process flow, reduce the process cost, and solve the problem of substrate warping caused by electroplating. The application of self-propagating film in chip welding or airtight packaging interface can reduce packaging cost and improve packaging efficiency and yield. In addition, the first self-propagating film pre-placed on the upper surface of the first metal pad can serve as a cheap substitute for the gold-tin solder of the chip, reducing the production cost of the overall device.

[0047] On the other hand, the embodiment of the present disclosure provides a dam substrate 200, which is obtained by the preparation method described above. The specific steps of the preparation method can refer to the relevant discussion above, and will not be repeated here. The dam substrate 200 includes a substrate body 210, a first metal pad 220, a second metal pad 230, a first self-propagating film 240 and a second self-propagating film 260.

[0048] The substrate body 210 is provided with at least one through hole (not shown in the figure) running through the thickness direction thereof. The first metal pad 220 is located on the upper surface of the substrate body 210. The second metal pad 230 is located on the lower surface of the substrate body 210, and the second metal pad 230 and the first metal pad 220 are connected by the filling metal in the through hole. The first self-propagating film 240 is located in the chip connection area and the dam connection area on the upper surface of the first metal pad 220. A dam frame material 250 is welded on the first self-propagating film 240 in the dam connection area. The second self-propagating film 260 is located on the upper surface of the dam frame material 250 for connecting the package board. The first self-propagating film in the chip connection area is used to connect the chip.

[0049] In actual application, the dam substrate of the embodiment of the present disclosure can reduce the dam process cost by more than 46%, and shorten the processing time to 30% of the traditional process. The thermal shock damage of chip packaging and quartz glass packaging to the substrate is reduced, and the substrate life is improved. The self-propagating film replaces the gold-tin solder on the back of the chip, which can reduce the cost of the UV device as a whole by more than 5%.

[0050] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present disclosure, but the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and substance of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A method for preparing a dam substrate, characterized in that: The method for preparing the dam substrate comprises: Providing a substrate body; At least one through hole is formed on the substrate body and extends through the substrate body in a thickness direction; forming a first photoresist pattern and a second photoresist pattern around the through hole on the upper and lower surfaces of the substrate body respectively; The through hole, the first photoresist pattern and the second photoresist pattern are filled with metal by an electroplating process to form a first metal pad and a second metal pad respectively located on the upper and lower surfaces of the substrate body, and two ends of the filling metal in the through hole are respectively connected to the first metal pad and the second metal pad; A first self-propagating film is evaporated on the chip connection area and the dam connection area on the upper surface of the first metal pad; a dam frame material is welded on the first self-propagating film in the dam connection area, and a second self-propagating film is evaporated on the upper surface of the dam frame material to connect the packaging board.

2. The method for preparing a dam substrate according to claim 1, characterized in that: Before forming the first photoresist pattern and the second photoresist pattern around the through hole, respectively, a metal seed layer is formed on the upper and lower surfaces of the substrate body and the inner wall of the through hole.

3. The method for preparing a dam substrate according to claim 2, characterized in that: The metal seed layer is a titanium layer or a copper layer, and the thickness of the metal seed layer is in the range of 0.5um-3um.

4. The method for preparing a dam substrate according to claim 1, characterized in that: The film systems of the first self-propagating film and the second self-propagating film both include at least one of Ti—Al, Al—Ni, Ti—Ni, Ni—Si, Nb—Si, Al—CuOx, and Al—Pt.

5. The method for preparing a dam substrate according to claim 4, characterized in that: The step of evaporating a first self-propagating thin film on the chip connection area and the dam connection area on the upper surface of the first metal pad comprises: forming a third photoresist pattern in a chip connection region and a dam connection region on the upper surface of the first metal pad; The third photoresist pattern is evaporated by an evaporation process to form the first self-propagating film located in the chip connection area and the dam connection area, and the thickness of the first self-propagating film ranges from 0.5um to 5um.

6. The method for preparing a dam substrate according to claim 1, characterized in that: The step of welding the dam frame material on the first self-propagating film in the dam connection area comprises: Processing the copper foil into the shape of the dam frame material by laser or etching, wherein the thickness of the copper foil is 0.2 mm to 0.6 mm; The dam frame material is welded to the dam connection area by any one of laser, heating and ignition.

7. The method for preparing a dam substrate according to claim 6, characterized in that: After welding the dam frame material to the dam connection area, the preparation method further comprises: The surfaces of the dam frame material, the first metal pad, the second metal pad and the substrate body are cleaned and plated with a surface finishing layer.

8. The method for preparing a dam substrate according to claim 7, characterized in that: The finishing layer is one of a silver layer, a nickel-gold layer and a nickel-palladium-gold layer, and the thickness of the finishing layer ranges from 0.5um to 5um.

9. The method for preparing a dam substrate according to any one of claims 1 to 8, characterized in that: The substrate body is one of an aluminum nitride ceramic substrate, an aluminum oxide ceramic substrate and a diamond substrate, the aperture size of the through hole is 50um-300um, and the thickness range of the second self-propagating film is 0.5um-5um.

10. A dam substrate, characterized in that: The dam substrate is obtained by the preparation method according to any one of claims 1 to 9, wherein the dam substrate comprises: A substrate body, wherein the substrate body is provided with at least one through hole penetrating the substrate body in a thickness direction; A first metal pad, wherein the first metal pad is located on the upper surface of the substrate body; A second metal pad, the second metal pad is located on the lower surface of the substrate body, and the second metal pad is connected to the first metal pad through a filling metal in the through hole; A first self-propagating film, wherein the first self-propagating film is located in a chip connection area and a dam connection area on the upper surface of the first metal pad; wherein a dam frame material is welded to the first self-propagating film in the dam connection area; A second self-propagating film is located on the upper surface of the dam frame material and is used for connecting the packaging board.

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