A sintering anti-dislocation method for 0.4mm thick copper of DCB substrate by wet process

Abstract

The application discloses a DCB substrate wet 0.4mm copper thickness sintering anti-misplacement method. The DCB substrate wet 0.4mm copper thickness sintering anti-misplacement method comprises the following steps: step one, baking 0.4mm thickness copper sheet in nitrogen, after cooling, cleaning the copper sheet, taking part of the copper sheet as the first surface copper sheet, and taking another part of the copper sheet as the second surface copper sheet after pre-bending; step two, wet oxidation of the first surface copper sheet and the second surface copper sheet; step three, sintering the first surface copper sheet of the DCB substrate, placing the first surface copper sheet with the concave surface downward above the ceramic sheet; and step four, sintering the second surface copper sheet of the DCB substrate, inverting the ceramic sheet, placing the second surface copper sheet with the concave surface upward above the ceramic sheet with the first surface copper sheet below the ceramic sheet. The application effectively solves the sintering misplacement problem.

Description

Technical Field

[0001] This invention relates to the field of DCB substrate manufacturing, specifically a method for preventing misalignment during sintering. Background Technology

[0002] When sintering the second side of a 0.4mm thick copper substrate using the wet process, misalignment (front-to-back misalignment or left-to-right misalignment, i.e., the copper sheet exceeds the ceramic sheet) is very likely to occur due to the large warping on one side and the varying curvature of the incoming copper sheets. Currently, there is no effective control method, and the misalignment rate is as high as 30-50%, causing misalignment and incomplete pattern defects in subsequent film lamination. Summary of the Invention

[0003] To address the problems existing in the prior art, the present invention provides a method for preventing misalignment by wet sintering of a 0.4mm thick copper substrate on a DCB substrate, thereby solving at least one of the above-mentioned technical problems.

[0004] To achieve the above objectives, the present invention provides a method for preventing misalignment during wet sintering of a 0.4mm thick copper substrate on a DCB substrate, characterized by comprising the following steps:

[0005] Step 1: Bake a 0.4mm thick copper sheet in nitrogen. After cooling, clean the copper sheet. Use a portion of the copper sheet as the first copper sheet and pre-bend the other portion of the copper sheet to use as the second copper sheet.

[0006] Step two: Wet oxidation is performed on the first and second copper sheets;

[0007] Step 3: Sinter the first copper sheet of the DCB substrate and place the first copper sheet with the concave side facing down on top of the ceramic sheet;

[0008] Step 4: Sinter the second copper sheet of the DCB substrate. Invert the ceramic sheet, with the first copper sheet below it, and place the second copper sheet with its concave side facing up on top of the ceramic sheet.

[0009] This invention effectively solves the problem of sintering misalignment.

[0010] In a further preferred embodiment, in step one, 100 copper sheets are stacked one on top of the other and then baked.

[0011] In a further preferred embodiment, in step one, when cleaning the copper sheet, degreasing, acid washing, and micro-etching are performed by chemical cleaning.

[0012] In a further preferred embodiment, in step one, the pre-bending radius of the second copper sheet along its long side is 300-500mm.

[0013] More preferably, in step one, the size of the copper sheet is 132mm*184mm.

[0014] Further preferred, in step one, baking is carried out at 290-400℃ in a nitrogen atmosphere for 30-180 minutes, with the oxygen content of the atmosphere controlled below 100ppm.

[0015] More preferably, the thickness of the ceramic tile is 0.32 mm.

[0016] More preferably, the ceramic sheet is ZTA. ZTA is zirconia-toughened alumina ceramic.

[0017] More preferably, the ceramic tile has a size of 138mm*190mm.

[0018] A method for preventing misalignment during wet sintering of a 0.4mm thick copper layer on a DCB substrate, characterized by comprising the following steps:

[0019] Step 1: Bake a 0.4mm thick copper sheet at 290-400℃ in a nitrogen atmosphere for 30-180 minutes, with the oxygen content of the atmosphere controlled below 100ppm.

[0020] After cooling, clean the copper sheets. Use a portion of the copper sheets as the first copper sheet and pre-bend the other portion to use as the second copper sheet. The size of the copper sheet is 132mm*184mm. The pre-bending radius of the second copper sheet is 300-500mm along the long side.

[0021] Step two: Wet oxidation is performed on the first and second copper sheets;

[0022] Step 3: Sinter the first copper sheet of the DCB substrate and place the first copper sheet with the concave side facing down on top of the ceramic sheet;

[0023] Step 4: Sinter the second copper sheet of the DCB substrate. Invert the ceramic sheet, with the first copper sheet below it, and place the second copper sheet with its concave side facing up on top of the ceramic sheet.

[0024] In step one, 100 copper sheets are stacked one on top of the other and then baked.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1) The original sintering method involved directly placing the oxidized copper sheet onto a single-sided copper-clad substrate for sintering (concave side down). This invention, however, involves heat-treating the incoming copper sheet and performing a pre-bending operation to ensure a consistent and appropriate curvature, neither too large nor too small. Furthermore, the copper sheet is placed with the concave side facing up during the second sintering. This improvement reduces the sintering misalignment rate from 30-50% to below 10%, resolving the sintering misalignment problem of the wet 0.4 / 0.32ZTA / 0.4 combination on the DCB substrate.

[0027] 2) A 0.4mm thick copper sheet (132*184mm) is heat-treated to induce recrystallization and reduce its yield strength. After cleaning, the 0.4mm copper sheet is pre-bent using a manual punch press to give it a certain curvature along its long side. During sintering, the wet-oxidized copper sheet is placed with the concave side facing up on a single-sided copper-coated ceramic plate. Attached Figure Description

[0028] Figure 1 This is a flowchart of the present invention;

[0029] Figure 2 This is a traditional structural diagram. Detailed Implementation

[0030] The present invention will now be further described with reference to the accompanying drawings.

[0031] See Figure 1 Specific Embodiment 1: A method for preventing misalignment during wet sintering of a 0.4mm thick copper layer on a DCB substrate, comprising the following steps:

[0032] Step 1: Bake a 0.4mm thick copper sheet in nitrogen. After cooling, clean the copper sheet. Use a portion of the copper sheet as the first copper sheet 2, and pre-bend the other portion of the copper sheet to use as the second copper sheet 3.

[0033] Step two: Wet oxidation is performed on the first and second copper sheets;

[0034] Step 3: Sinter the first copper sheet 2 of the DCB substrate. Place the first copper sheet 2 with its concave side facing down on top of the ceramic sheet 1. (See attached image) Figure 1 (a) in the middle;

[0035] Step 4: Sinter the second copper sheet 3 of the DCB substrate. Invert the ceramic sheet 1, with the first copper sheet 2 below the ceramic sheet 1, and place the second copper sheet 3 with its concave side facing up above the ceramic sheet 1. See [link to relevant documentation]. Figure 1 (b) in the middle.

[0036] In step one, 100 copper sheets are stacked one on top of the other and then baked.

[0037] In step one, when cleaning the copper sheet, chemical cleaning is used to remove oil, pickle, and micro-etch.

[0038] In step one, the pre-bending radius of the second copper sheet 3 along its long side is 300-500mm. The dimensions of the copper sheet in step one are 132mm*184mm.

[0039] In step one, the ceramic sheet is baked at 290-400℃ in a nitrogen atmosphere for 30-180 minutes, with the oxygen content controlled below 100ppm. The thickness of ceramic sheet 1 is 0.32mm. The dimensions of ceramic sheet 1 are 138mm*190mm. Ceramic sheet 1 is ZTA, which stands for Zirconia Toughened Alumina Ceramic.

[0040] Specifically, a method for preventing misalignment during wet sintering of a 0.4mm thick copper layer on a DCB substrate includes the following steps:

[0041] Step 1: Bake a 0.4mm thick copper sheet at 290-400℃ in a nitrogen atmosphere for 30-180 minutes, with the oxygen content of the atmosphere controlled below 100ppm.

[0042] After cooling, the copper sheets are cleaned. A portion of the copper sheets is used as the first copper sheet 2, and the other portion of the copper sheets is pre-bent to become the second copper sheet 3. The size of the copper sheet is 132mm*184mm. The pre-bending radius of the second copper sheet 3 in the long side direction is 300-500mm.

[0043] Step two: Wet oxidation is performed on the first and second copper sheets;

[0044] Step 3: Sinter the first copper sheet 2 of the DCB substrate, placing the first copper sheet 2 with its concave side facing down on top of the ceramic sheet 1; see [link / reference] Figure 1 (a) in the middle;

[0045] Step four: Sinter the second copper sheet 3 of the DCB substrate. Invert the ceramic sheet 1, with the first copper sheet 2 below the ceramic sheet 1. Place the second copper sheet 3, concave side up, above the ceramic sheet 1. (See below) Figure 1 (b) in the middle.

[0046] When a single-sided copper-clad ceramic substrate undergoes sintering on its second side and is heated in the sintering furnace, the difference in expansion coefficients between the ceramic and copper causes warping along its length. This is particularly pronounced when a 0.32mm ceramic sheet is paired with a 0.4mm thick copper-clad ceramic substrate, resulting in more significant warping during heating. During heating, the copper sheet on the second side extends beyond the top of the warped copper-clad ceramic substrate. (See [link to documentation]). Figure 2 Misalignment occurs. The sintering method of this invention is as follows: Figure 1 In (b), when the temperature rises, because the copper sheet has a certain curvature, the copper sheet will not exceed the copper-clad ceramic substrate where warping occurs, thus greatly reducing the probability of misalignment.

[0047] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preventing misalignment during wet sintering of a 0.4mm thick copper layer on a DCB substrate, characterized in that, Includes the following steps: Step 1: Bake a 0.4mm thick copper sheet in nitrogen. After cooling, clean the copper sheet. Use a portion of the copper sheet as the first copper sheet and pre-bend the other portion of the copper sheet to use as the second copper sheet. Step two: Wet oxidation is performed on the first and second copper sheets; Step 3: Sinter the first copper sheet of the DCB substrate and place the first copper sheet with the concave side facing down on top of the ceramic sheet; Step 4: Sinter the second copper sheet of the DCB substrate. Invert the ceramic sheet, with the first copper sheet below it, and place the second copper sheet with its concave side facing up on top of the ceramic sheet.

2. The method for preventing misalignment during wet sintering of a 0.4mm thick copper layer on a DCB substrate according to claim 1, characterized in that: In step one, 100 copper sheets are stacked one on top of the other and then baked.

3. The method for preventing misalignment during wet sintering of a 0.4mm thick copper layer on a DCB substrate according to claim 1, characterized in that: In step one, when cleaning the copper sheet, chemical cleaning is used to remove oil, pickle, and micro-etch.

4. The method for preventing misalignment during wet sintering of a 0.4mm thick copper layer on a DCB substrate according to claim 1, characterized in that: In step one, the pre-bending radius of the second copper sheet along its long side is 300-500mm.

5. The method for preventing misalignment during wet sintering of a 0.4mm thick copper layer on a DCB substrate according to claim 1, characterized in that: In step one, the copper sheet measures 132mm x 184mm.

6. The method for preventing misalignment during wet sintering of a 0.4mm thick copper layer on a DCB substrate according to claim 1, characterized in that: In step one, bake at 290-400℃ in a nitrogen atmosphere for 30-180 minutes, with the oxygen content of the atmosphere controlled below 100ppm.

7. The method for preventing misalignment during wet sintering of a 0.4mm thick copper layer on a DCB substrate according to claim 1, characterized in that: The thickness of the ceramic tile is 0.32 mm.

8. The method for preventing misalignment during wet sintering of a 0.4mm thick copper layer on a DCB substrate according to claim 1, characterized in that: The ceramic tile is ZTA.

9. A method for preventing misalignment during wet sintering of a 0.4mm thick copper layer on a DCB substrate, characterized in that... Includes the following steps: Step 1: Bake a 0.4mm thick copper sheet at 290-400℃ in a nitrogen atmosphere for 30-180 minutes, with the oxygen content of the atmosphere controlled below 100ppm. After cooling, clean the copper sheets. Use a portion of the copper sheets as the first copper sheet and pre-bend the other portion to use as the second copper sheet. The size of the copper sheet is 132mm*184mm. The pre-bending radius of the second copper sheet is 300-500mm along the long side. Step two: Wet oxidation is performed on the first and second copper sheets; Step 3: Sinter the first copper sheet of the DCB substrate and place the first copper sheet with the concave side facing down on top of the ceramic sheet; Step 4: Sinter the second copper sheet of the DCB substrate. Invert the ceramic sheet, with the first copper sheet below it, and place the second copper sheet with its concave side facing up on top of the ceramic sheet.

10. The method for preventing misalignment during wet sintering of a 0.4mm thick copper layer on a DCB substrate according to claim 9, characterized in that: In step one, 100 copper sheets are stacked one on top of the other and then baked.

Images