A method of evaporation for one-step formation of metal lines and via wall metallization

Abstract

The application relates to the field of electronic technology, in particular to a metal line and through-hole hole wall metallization one-time forming evaporation method; a ceramic substrate with holes is obtained; a placeholder mold is made according to the hole position of the through-hole of the ceramic substrate; the through-hole of the ceramic substrate is filled by using the placeholder mold to obtain an assembly body; a mask layer is made through a photoresist process to expose the surface line and the through-hole area; the placeholder mold is removed, and nitrogen is used for blowing and removing the debris and particulate matters to obtain a to-be-plated piece; the angle between the to-be-plated piece and an evaporation source is adjusted to 60 degrees; a metal film is evaporated; the photoresist is removed to obtain one-time formed metal lines and metallized through-holes; through the above mode, the high metal line and the through-hole hole wall metallization can be completed at one time, and the metallization performance and the production efficiency are improved.

Description

Technical Field

[0001] This invention relates to the field of electronic technology, and in particular to a vapor deposition method for one-time metallization of metal circuits and through-hole walls. Background Technology

[0002] Metallized vias on ceramic substrates are a common design in the electronics field, used to achieve double-sided circuitry and signal transmission. Common methods include paste adsorption and filling, or cold pressing with copper sheets. These processes result in solid metallized vias. When the via size is small and their arrangement is dense, the mismatch in thermal expansion coefficients between the filler material and the ceramic substrate significantly increases the risk of thermal breakage. To avoid this problem, a preferred solution is to use hollow metallized vias. Ideally, the area to be metallized is prepared using photoresist, hard mask, or other masking processes, followed by metallization using methods such as vacuum evaporation.

[0003] However, the above scheme will face many difficulties in actual operation: (1) When making high-precision metal lines, the processing accuracy of the hard mask cannot meet the requirements; (2) When the photoresist is covered, it will be trapped in the through hole of the substrate, and there is a great risk of abnormal residue in the hole after development; (3) In the conventional evaporation process, the evaporation direction of the through hole and the evaporation source are almost parallel, resulting in a low growth rate of the metal film in the hole and poor coating effect; (4) Prioritize the metallization of the through hole wall and then make metal lines for connection, which requires two coatings, and the time and material costs are high.

[0004] In conclusion, it is essential to propose a vapor deposition method that can complete the metallization of high-metal circuits and through-hole walls in one step, thereby improving metallization performance and production efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a vapor deposition method for one-time metallization of metal lines and through-hole walls, which enables high-metallization of metal lines and through-hole walls to be completed in one step, thereby improving metallization performance and production efficiency.

[0006] To achieve the above objectives, the present invention employs a vapor deposition method for one-time metallization of metal circuits and through-hole walls, comprising the following steps:

[0007] Obtain a perforated ceramic substrate;

[0008] Based on the hole positions of the through holes in the ceramic substrate, a placeholder mold is made;

[0009] The assembly is obtained by filling the through holes of the ceramic substrate with a placeholder mold;

[0010] A mask layer is created using photoresist technology to expose surface circuitry and via areas.

[0011] Remove the spacer mold and purge with nitrogen to remove debris and particulate matter, obtaining the wafer to be plated;

[0012] Adjust the angle between the substrate to be coated and the evaporation source to 60°;

[0013] Evaporated metal film;

[0014] Remove the photoresist to obtain a one-piece molded metal circuit and metallized via.

[0015] In the step of obtaining a porous ceramic substrate:

[0016] Ceramic substrates are processed by mechanical punching and laser drilling.

[0017] In the step of fabricating a spacer mold based on the hole positions of the through holes in the ceramic substrate:

[0018] Locate the positions of the holes in the ceramic substrate, and fabricate corresponding pillars on the base plate with a diameter smaller than the hole diameter. The height of the pillars should be the same as the thickness of the ceramic substrate.

[0019] In the step of filling the through holes of the ceramic substrate with a placeholder mold to obtain the assembly:

[0020] Align the through holes with the mold pillars one by one, and insert the pillars into the through holes.

[0021] In the step of creating a mask layer using photoresist to expose surface circuits and via areas:

[0022] Photoresist is applied to the upper surface of the assembly using spin coating and spray coating processes.

[0023] In the step of depositing the metal film:

[0024] Metal films are prepared by vacuum evaporation using different film materials.

[0025] In the step of removing the photoresist to obtain a one-time formed metal circuit and metallized via:

[0026] The photoresist was removed by soaking in a resist remover solution and using ultrasound. After rinsing with pure water, the target product was obtained.

[0027] This invention discloses a vapor deposition method for one-time metallization of metal lines and through-hole walls. The method involves: obtaining a perforated ceramic substrate; fabricating a spacer mold based on the hole positions of the through-holes in the ceramic substrate; filling the through-holes in the ceramic substrate using the spacer mold to obtain an assembly; fabricating a mask layer using photoresist to expose the surface lines and through-hole areas; removing the spacer mold and purging with nitrogen to remove debris and particles to obtain the wafer to be deposited; adjusting the angle between the wafer to be deposited and the evaporation source to 60°; vapor deposition of a metal film; and removing the photoresist to obtain a one-time metallized metal line and metallized through-hole. This method enables the one-time completion of metallization of high-quality metal lines and through-hole walls, improving metallization performance and production efficiency. Attached Figure Description

[0028] 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.

[0029] Figure 1 This is a flowchart of the vapor deposition method for one-time metallization of metal circuits and through-hole walls according to the present invention.

[0030] Figure 2 This is a schematic diagram of the structure of the ceramic substrate of the present invention.

[0031] Figure 3 This is a schematic diagram of the structure of the placeholder mold of the present invention.

[0032] Figure 4 This is a schematic diagram of the structure of the ceramic substrate and the spacer mold of the present invention.

[0033] 1-Ceramic substrate, 2-Placeholder mold. Detailed Implementation

[0034] Please see Figures 1 to 4 ,in Figure 1 This is a flowchart illustrating the steps of a vapor deposition method for one-step metallization of metal circuits and through-hole walls. Figure 2 This is a schematic diagram of the structure of a ceramic substrate. Figure 3 This is a structural diagram of the placeholder mold. Figure 4 This is a schematic diagram of the structure of the ceramic substrate and the spacer mold.

[0035] This invention provides a vapor deposition method for one-time metallization of metal circuits and through-hole walls, comprising the following steps:

[0036] S1: Obtain a ceramic substrate 1 with holes, and process the ceramic substrate 1 by mechanical punching and laser drilling;

[0037] S2: Based on the hole positions of the through holes in the ceramic substrate 1, make a placeholder mold 2 to position the holes in the ceramic substrate 1. Make corresponding pillars with a diameter smaller than the hole diameter on the base plate. The height of the pillars is consistent with the thickness of the ceramic substrate 1.

[0038] S3: Use the placeholder mold 2 to fill the through holes of the ceramic substrate 1 to obtain the assembly. Match the through holes with the mold columns one by one and insert the columns into the through holes.

[0039] S4: A mask layer is made using photoresist technology to expose the surface circuits and via areas. Photoresist is then applied to the upper surface of the assembly using spin coating and spray coating processes.

[0040] S5: Remove the spacer mold 2 and purge with nitrogen to remove debris and particles to obtain the wafer to be plated;

[0041] S6: Adjust the angle between the substrate to be plated and the evaporation source to 60°;

[0042] S7: Metal films are prepared by vacuum evaporation using different film materials;

[0043] S8: Remove the photoresist to obtain a one-piece molded metal circuit and metallized via. The photoresist is removed by soaking in a photoresist remover solution and by ultrasonication. After rinsing with pure water, the target product is obtained.

[0044] In this embodiment, a perforated ceramic substrate 1 is first obtained and processed by mechanical punching and laser drilling. Then, a spacer mold 2 is fabricated according to the hole positions of the ceramic substrate 1 to locate the holes. Correspondingly, columns with diameters smaller than the hole diameters are fabricated on a base plate, with the height of the columns matching the thickness of the ceramic substrate 1. The columns are made of aluminum, polyimide, or quartz glass. The specific processing method, such as machining, 3D printing, or etching, is determined based on the size and precision requirements. Finally, the spacer mold 2 is used to fill the perforated area. The through holes in the ceramic substrate 1 are used to obtain the assembly. The through holes are then aligned with the mold pillars, which are inserted into the through holes. Since the height of the pillars is the same as the thickness of the ceramic substrate 1, the upper surface of the pillars is relatively horizontal to the upper surface of the ceramic substrate 1 after fixing. If a slight height difference exists due to processing precision limitations, it will not affect the function of the spacer mold 2. A mask layer is then created using photoresist to expose the surface circuitry and through-hole areas. Photoresist is then applied to the upper surface of the assembly using spin coating and spray coating processes. Due to the surface tension of the photoresist, the photoresist will not... Excessive photoresist seeps into the gap between the inner wall of the through-hole and the pillar. After ultraviolet exposure and development, the photoresist is etched into a specific circuit pattern, serving as a mask layer. Next, the spacer mold 2 is removed, and nitrogen gas is used to purge away debris and particles, yielding the wafer to be plated. The angle between the wafer to be plated and the evaporation source is then adjusted to 60°. This adjustment can be achieved by designing angled pads on a standard workpiece tray to ensure that the angle between the clamped ceramic substrate 1 and the evaporation source reaches the design value; alternatively, the electron beam angle can be adjusted to change the evaporation angle of the evaporation source, thus achieving the set angle between the source and the ceramic substrate 1. Metal films are prepared by vacuum evaporation using different film materials. Due to the rotation or rotation of the workpiece during the coating process, the coating uniformity is good. If higher uniformity is required, a correction plate can be added to adjust the specific thickness. Finally, the photoresist is removed to obtain a one-time formed metal circuit and metallized via. The photoresist is removed by immersion in a photoresist remover and ultrasonic cleaning. After cleaning with pure water, the target product is obtained. If the back of the product also has circuit and via metallized design, the above steps are repeated to obtain a product with higher reliability and better integration.

[0045] Example 1:

[0046] Select a 2-inch ceramic substrate 1 with a thickness of 0.5mm and a through hole diameter of 0.4-0.45mm. Drill 400 holes on each 2-inch substrate. Then, customize a spacer mold 2 made of polyimide material according to the hole positions of the ceramic substrate 1. The base plate thickness is 1mm, the column diameter is 0.32-0.37mm, and the column height is 0.5mm.

[0047] After combining the two, an 8μm thick photoresist layer is prepared by spraying photoresist. After exposure and development, a line area to be plated with a line width of 50μm is obtained. Then, the placeholder mold 2 is removed. Since polyimide has a certain toughness, the mold can be easily removed by stretching the base plate.

[0048] The ceramic substrate 1 is fixed on a pad plane at a 60° angle to the evaporation direction of the evaporation source, and then a 3.3 μm thick metal film is prepared by electron beam evaporation in a vacuum environment. After the film is deposited, the ceramic substrate 1 is removed, and the surface photoresist mask is removed with a resist remover to obtain a one-time formed metal line and metallized hole wall.

[0049] Example 2:

[0050] A 2-inch ceramic substrate 1 with a thickness of 0.15mm and a through hole diameter of 0.11-0.13mm is selected, and 2304 holes are drilled on each 2-inch substrate. A quartz glass spacer mold 2 is then customized according to the hole positions of the ceramic substrate 1. The mold is made by etching process with high precision, with a base plate thickness of 0.65mm, a column diameter of 0.07-0.09mm, and a column height of 0.15mm.

[0051] After combining the two, a 5μm thick photoresist layer is prepared by spin coating. After exposure and development, a line area to be plated with a line width of 20μm is obtained. Then, the placeholder mold 2 is removed. Since the pillar is too small to be removed without damage, the base plate is removed by breaking the pillar. Then, the through hole is purged with nitrogen to remove the remaining pillar.

[0052] The ceramic substrate 1 is fixed on the surface of a conventional horizontal workpiece disk. The electron beam angle is adjusted so that the corresponding evaporation beam angle is at a 60° angle with the ceramic substrate 1. Then, a 1.0 μm thick metal film is deposited in a vacuum environment. After the film is deposited, the ceramic substrate 1 is removed. Due to the high precision of the circuit and the very dense arrangement of the holes, ultrasonic stripping of the stripping solution is added on the basis of immersion in the stripping solution to remove the photoresist and obtain high precision circuits and precision metallized through holes.

[0053] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A vapor deposition method for one-time metallization of metal circuits and through-hole walls, characterized in that, Includes the following steps: Obtain a perforated ceramic substrate; Based on the hole positions of the through holes in the ceramic substrate, a placeholder mold is made; wherein the diameter of the column of the placeholder mold is smaller than the diameter of the through holes in the ceramic substrate, and the height of the column is the same as the thickness of the ceramic substrate. The assembly is obtained by filling the through holes of the ceramic substrate with a placeholder mold; A mask layer is fabricated using photoresist technology to expose surface circuits and via areas. Photoresist is then applied to the upper surface of the assembly using spin coating and spray coating processes. Remove the spacer mold and purge with nitrogen to remove debris and particulate matter, obtaining the wafer to be plated; Adjust the angle between the substrate to be plated and the evaporation source to 60°; Evaporated metal film; Remove the photoresist to obtain a one-piece molded metal circuit and metallized via.

2. The vapor deposition method for one-time metallization of metal lines and through-hole walls as described in claim 1, characterized in that, In the steps of obtaining a porous ceramic substrate: Ceramic substrates are processed by mechanical punching and laser drilling.

3. The vapor deposition method for one-time metallization of metal lines and through-hole walls as described in claim 1, characterized in that, In the step of fabricating a spacer mold based on the hole positions of the through holes in the ceramic substrate: Locate the positions of the holes in the ceramic substrate, and fabricate corresponding pillars on the base plate with a diameter smaller than the hole diameter. The height of the pillars should be the same as the thickness of the ceramic substrate.

4. The vapor deposition method for one-time metallization of metal lines and through-hole walls as described in claim 3, characterized in that, In the step of filling the through holes of the ceramic substrate with a placeholder mold to obtain the assembly: Align the through holes with the mold pillars one by one, and insert the pillars into the through holes.

5. The vapor deposition method for one-time metallization of metal lines and through-hole walls as described in claim 1, characterized in that, In the step of vapor deposition of metal films: Metal films are prepared by vacuum evaporation using different film materials.

6. The vapor deposition method for one-time metallization of metal lines and through-hole walls as described in claim 1, characterized in that, In the step of removing photoresist to obtain a one-piece formed metal circuit and metallized via: The photoresist was removed by soaking in a resist remover solution and using ultrasound. After rinsing with pure water, the target product was obtained.

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