A process design for improving the ts life of a copper-clad ceramic substrate

Abstract

The application discloses a process design for improving the TS life of a copper-clad ceramic substrate, and specifically comprises the following steps: S1, cleaning the surface of the copper-clad ceramic substrate; S2, simultaneously covering a layer of photosensitive dry film on the front and back surfaces of the copper-clad ceramic substrate through a film press; S3, aligning the front and back film negatives to ensure that the front and back patterns are not deviated, and then performing exposure; S4, removing the photosensitive dry film in the unexposed area through an alkaline developing solution, and retaining the required dry film; S5, horizontally placing the developed copper-clad ceramic substrate in a vacuum etching line body to perform vacuum etching; S6, using a prepared solder removal liquid to remove the solder on the etched copper-clad ceramic substrate, so that no solder is retained in the groove; and S7, performing pattern etching again, so that the solder can be partially exposed, and the obtained solder retention is not connected, and the reliability of the product is improved, and the cold and hot impact times are high.

Description

Technical Field

[0001] This invention relates to the field of copper-clad ceramic substrate technology, and particularly to a process design for improving the TS (traceability) lifespan of copper-clad ceramic substrates. Background Technology

[0002] Copper-clad ceramic substrates possess excellent thermal cycling properties, shape stability, high rigidity, high thermal conductivity, and high reliability. Various patterns can be etched onto the copper-clad surface. Furthermore, it is a pollution-free and environmentally friendly product with a wide operating temperature range of -55℃ to 850℃. Its coefficient of thermal expansion is close to that of silicon, making it suitable for a wide range of applications: semiconductor coolers, electronic heaters, high-power semiconductor modules, power control circuits, hybrid power circuits, intelligent power components, high-frequency switching power supplies, solid-state relays, automotive electronics, aerospace and military electronic components, solar panel components, telecommunications switches and receiving systems, and laser industrial electronics.

[0003] After the existing copper-clad ceramic substrate is etched with patterned circuits according to the product design, a solder removal process is performed to make the copper bottom and solder layer basically flush, with no solder remaining in the trench. After the copper-clad ceramic substrate is etched with patterned circuits according to the product design and a solder removal process is performed, the thermal shock performance is poor, and the number of thermal shock cycles is less than the standard number. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to address the shortcomings of the prior art and provide a process design to improve the TS lifespan of copper-clad ceramic substrates.

[0005] Technical solution: A process design to improve the TS (transfer-to-trace) lifespan of copper-clad ceramic substrates, the specific steps of which include: S1. Use a micro-etching agent to lightly etch the surface of the copper-clad ceramic substrate to remove the oxides on the surface. Then, clean the surface of the copper-clad ceramic substrate by acid washing and water washing. After cleaning and drying, check whether the copper layer surface is clean to avoid affecting the subsequent manufacturing process. S2. A photosensitive dry film is simultaneously applied to both sides of the copper-clad ceramic substrate using a laminating machine to prepare for subsequent pattern transfer; S3. The prepared front and back film negatives are mounted on the glass stage of the exposure machine. The operator aligns the two film negatives using a charge-coupled device (CCD) and visual alignment to ensure that the front and back patterns are without deviation. After alignment, the operator places the copper-clad ceramic substrate between the two films and selects an appropriate exposure energy based on the thickness of the dry film for exposure. S4. After exposure, the photosensitive dry film covering the surface of the copper-clad ceramic substrate will show different colors. The photosensitive dry film in the unexposed areas is removed by alkaline developing solution, and the required dry film will be retained on the surface of the copper-clad ceramic substrate. S5. Place the developed copper-clad ceramic substrate horizontally on the vacuum etching line for vacuum etching. Adjust the line speed according to the thickness of the copper layer of the copper-clad ceramic substrate. The copper layer without photosensitive dry film protection will undergo an oxidation-reduction reaction with the etching solution, thereby removing the copper layer, forming the required trench, and the solder in the trench can be exposed, with the solder in the trench protruding from the copper layer. S6. Use the prepared solder removal solution to remove the solder from the etched copper-clad ceramic substrate, so that no solder remains in the trench; S7. Repeat the process from S1 to S5 in sequence, and perform another pattern etching. The etching line speed is faster in the second etching than in the first etching, so that the solder can be partially exposed, and the resulting solder is retained but not connected.

[0006] A further improvement of the present invention is that, in step S1, the temperature range of the micro-etching agent is 25–35°C.

[0007] A further improvement of the present invention is that, in step S1, the etching time of the micro-etchant ranges from 0.5 to 2.5 min.

[0008] A further improvement of the present invention is that, in step S2, the thickness of the photosensitive dry film ranges from 20 to 60 μm.

[0009] A further improvement of the present invention is that, in step S3, when the charge-coupled device (CCD) is aligned, a dedicated CCD camera, an industrial lens, and a light source are used to take pictures of the feature positions. The image data is collected by an image processor for image processing, and position calculations are performed to determine the actual position. The actual offset value is calculated by comparing it with the previously set reference position, which is used for high-precision alignment of the two film negatives.

[0010] A further improvement of the present invention is that, in step S5, the speed range is 1 to 2.5 m / min.

[0011] Compared with the prior art, the process design for improving the TS (transfer time) life of copper-clad ceramic substrates provided by the present invention achieves at least the following beneficial effects: This invention is applicable to the circuit board manufacturing process of copper-clad ceramic substrates. It involves two etching processes, in which the solder protrudes from the copper layer in the trench, allowing the solder to be partially exposed while remaining unconnected. This ensures functional separation and improves the thermal shock resistance of the product, thereby enhancing its reliability. The TS performance is excellent, and the thermal shock resistance can reach 3500 cycles, exceeding the standard value. Attached Figure Description

[0012] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0013] Figure 1 This is a schematic diagram of the circuits of the present invention.

[0014] Figure reference numerals: 1-copper layer, 2-solder, 3-copper-clad ceramic substrate. Detailed Implementation

[0015] Various exemplary embodiments of the present invention will now be described in detail. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0016] Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0017] like Figure 1 As shown, a process design for improving the TS (Transfer-Side) lifespan of copper-clad ceramic substrates includes the following steps: S1. Use a micro-etching agent to lightly etch the surface of the copper-clad ceramic substrate to remove the oxides on the surface. Then, clean the surface of the copper-clad ceramic substrate by acid washing and water washing. After cleaning and drying, check whether the copper layer surface is clean to avoid affecting the subsequent manufacturing process. S2. A photosensitive dry film is simultaneously applied to both sides of the copper-clad ceramic substrate using a laminating machine to prepare for subsequent pattern transfer; S3. The prepared front and back film negatives are mounted on the glass stage of the exposure machine. The operator aligns the two film negatives using a charge-coupled device (CCD) and visual alignment to ensure that the front and back patterns are without deviation. After alignment, the operator places the copper-clad ceramic substrate between the two films and selects an appropriate exposure energy based on the thickness of the dry film for exposure. S4. After exposure, the photosensitive dry film covering the surface of the copper-clad ceramic substrate will show different colors. The photosensitive dry film in the unexposed areas is removed by alkaline developing solution, and the required dry film will be retained on the surface of the copper-clad ceramic substrate. S5. The developed copper-clad ceramic substrate is placed horizontally in the vacuum etching line for vacuum etching. The line speed is adjusted to a suitable speed according to the thickness of the copper layer 1 of the copper-clad ceramic substrate 3. The copper layer 1 without photosensitive dry film protection will undergo an oxidation-reduction reaction with the etching solution, thereby removing the copper layer 1 and forming the required trench. The solder 2 in the trench can be exposed and protrudes from the copper layer 1. S6. Use the prepared solder removal solution to remove the solder from the etched copper-clad ceramic substrate, so that no solder remains in the trench; S7. Repeat the process from S1 to S5 in sequence, and perform another pattern etching. The etching line speed is faster in the second etching than in the first etching, so that the solder can be partially exposed, and the resulting solder is retained but not connected.

[0018] A further improvement of the present invention is that, in step S1, the temperature range of the micro-etching agent is 25–35°C.

[0019] A further improvement of the present invention is that, in step S1, the etching time of the micro-etchant ranges from 0.5 to 2.5 min.

[0020] A further improvement of the present invention is that, in step S2, the thickness of the photosensitive dry film is in the range of 20 to 60 μm.

[0021] A further improvement of the present invention is that, in step S3, when the charge-coupled device (CCD) is aligned, a dedicated CCD camera, an industrial lens, and a light source are used to take pictures of the feature positions. The image data is collected by an image processor for image processing, and position calculations are performed to determine the actual position. The actual offset value is calculated by comparing it with the previously set reference position, which is used for high-precision alignment of the two film negatives.

[0022] A further improvement of the present invention is that, in step S5, the speed range is 1 to 2.5 m / min.

[0023] In summary, the present invention provides a process design for improving the thermal shock resistance (TS) life of copper-clad ceramic substrates. This design is applicable to circuit board manufacturing processes using copper-clad ceramic substrates. It involves a two-stage etching process, where the solder protrudes from the copper layer within the trenches, allowing the solder to be partially exposed while remaining unconnected. This ensures functional separation while improving the product's thermal shock resistance, thereby enhancing reliability. The TS performance is excellent, achieving up to 3500 thermal shock cycles, exceeding the standard value.

[0024] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A process design for improving the TS (Transfer Term) lifespan of copper-clad ceramic substrates, characterized in that, The specific steps include: S1. Use a micro-etching agent to lightly etch the surface of the copper-clad ceramic substrate to remove the oxides on the surface. Then, clean the surface of the copper-clad ceramic substrate by acid washing and water washing. After cleaning and drying, check whether the copper layer surface is clean to avoid affecting the subsequent manufacturing process. S2. A photosensitive dry film is simultaneously applied to both sides of the copper-clad ceramic substrate using a laminating machine to prepare for subsequent pattern transfer; S3. The prepared front and back film negatives are mounted on the glass stage of the exposure machine. The operator aligns the two film negatives using a charge-coupled device (CCD) and visual alignment to ensure that the front and back patterns are without deviation. After alignment, the operator places the copper-clad ceramic substrate between the two films and selects an appropriate exposure energy based on the thickness of the dry film for exposure. S4. After exposure, the photosensitive dry film covering the surface of the copper-clad ceramic substrate will show different colors. The photosensitive dry film in the unexposed areas is removed by alkaline developing solution, and the required dry film will be retained on the surface of the copper-clad ceramic substrate. S5. The developed copper-clad ceramic substrate is placed horizontally in the vacuum etching line for vacuum etching. The line speed is adjusted to a suitable speed according to the thickness of the copper layer (1) of the copper-clad ceramic substrate (3). The copper layer (1) without photosensitive dry film protection will undergo an oxidation-reduction reaction with the etching solution, thereby removing the copper layer (1) and forming the required trench. The solder (2) in the trench can be exposed and protrudes from the copper layer (1). S6. Use the prepared solder removal solution to remove the solder from the etched copper-clad ceramic substrate, so that no solder remains in the trench; S7. Repeat the process from S1 to S5 in sequence, and perform another pattern etching. The etching line speed is faster in the second etching than in the first etching, so that the solder can be partially exposed, and the resulting solder is retained but not connected.

2. The process design for improving the TS lifespan of copper-clad ceramic substrates according to claim 1, characterized in that, In step S1, the temperature range of the micro-etching agent is 25–35°C.

3. The process design for improving the TS lifespan of copper-clad ceramic substrates according to claim 1, characterized in that, In step S1, the etching time of the micro-etchant ranges from 0.5 to 2.5 min.

4. The process design for improving the TS lifespan of copper-clad ceramic substrates according to claim 1, characterized in that, In step S2, the thickness of the photosensitive dry film ranges from 20 to 60 μm.

5. The process design for improving the TS lifespan of copper-clad ceramic substrates according to claim 1, characterized in that, In step S3, when aligning the charge-coupled device (CCD), a dedicated CCD camera, an industrial lens, and a light source are used to capture images of the feature positions. The image data is then collected by an image processor for image processing, and position calculations are performed to determine the actual position. The actual offset value is calculated by comparing it with the previously set reference position, which is used for high-precision alignment of the two film negatives.

6. The process design for improving the TS lifespan of copper-clad ceramic substrates according to claim 1, characterized in that, In step S5, the speed range is 1 to 2.5 m / min.

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