Process for surface metal planarization after hole filling of glass through hole process

Abstract

The invention discloses a process for surface metal planarization after hole filling of a glass through hole process. Compared with the prior art, mechanical grinding and polishing are added before existing chemical mechanical planarization polishing, the masonry grinding pad is high in hardness and does not deform, and polishing liquid does not contain corrosive chemical agents and does not have chemical reaction on metal, so that in the polishing process, it can be guaranteed that only the protruding part of the polishing surface is polished, and the polishing quality is improved. After polishing is finished, almost no height difference exists between the two materials; meanwhile, due to the fact that the surface is in a relatively flat state during fine polishing, it can be guaranteed that the height difference between the two materials of a final finished product reaches a very small level only by keeping the consistency of the removal rates of the two materials during fine polishing; and moreover, the chemical mechanical polishing time is shortened, and the cost is effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of metal planarization and polishing, and in particular to a process for planarizing the surface metal after filling a through-glass via process. Background Art

[0002] After the product is electroplated and the holes are filled, an uneven metal layer will remain on the surface of the wafer, which needs to be planarized by chemical mechanical polishing. However, the existing chemical mechanical planarization polishing process has two problems: 1. In order to improve the polishing efficiency of metals, corrosive chemicals are usually added to the polishing liquid, which will cause the pits on the surface of the wafer to react chemically with the polishing liquid, making it impossible to polish flat. Figure 1 As shown; 2. After the surface metal is polished off, two different materials need to be polished at the same time, which will lead to differences in processing rates and height differences between the two materials; In summary, the height difference between the two materials in the existing process can only be controlled to 50-100nm. Figure 2 shown.

[0003] As product requirements gradually increase, the previous metal chemical mechanical polishing and flattening process can no longer meet product needs. Based on the above problems, we need to develop a new glass through-hole process to flatten the surface metal after filling the hole, reduce the height difference between the two materials, and thus meet product needs. Summary of the invention

[0004] To solve the above technical problems, the present invention designs a process for flattening the surface metal after filling the through-glass via process, which reduces the height difference between the two materials during the chemical mechanical polishing of the surface metal after filling the through-glass via process, improves product performance and maintains industry competitiveness.

[0005] The present invention adopts the following technical solution: A process for planarizing the surface metal after filling a through-glass via, the process steps being: S1. Mechanical grinding and rough polishing: Use a diamond grinding pad and 2μm alumina powder to mechanically grind and rough polish the metal on the surface of the product for a certain period of time to reduce the thickness of the metal on the surface of the product so that the height difference of the product surface after polishing is less than 5nm; S2. Chemical mechanical fine polishing: Use 100nm silicon oxide polishing liquid and polyurethane polishing pad for fine polishing to remove the remaining metal on the surface and improve the roughness. At the same time, according to the selection ratio of the two processing materials in the product, add a corresponding proportion of corrosive chemicals to react chemically with the metal to ensure that the removal rates of the two materials are kept at a similar level, so that the height difference between the two materials on the surface of the polished product is less than 10nm.

[0006] Preferably, in step S1, the mechanical grinding and rough polishing takes 15-30 minutes.

[0007] Preferably, in the step S1, the thickness of the metal on the surface of the product is reduced to 10-20 μm.

[0008] Preferably, in step S2, the chemical mechanical polishing time is 10 to 20 minutes.

[0009] Preferably, in step S2, the amount of surface thickness removed from the product is 5-10 μm.

[0010] Preferably, the metal on the surface of the product is copper, and the substrate material of the product is glass.

[0011] Preferably, in step S2, the chemical agent added is hydrogen peroxide.

[0012] Preferably, the ratio of the polishing liquid to hydrogen peroxide is 100:7.5.

[0013] The beneficial effects of the present invention are as follows: the present invention adds mechanical grinding and polishing before the existing chemical mechanical flattening polishing; the brick and stone grinding pad has high hardness and will not deform; the polishing liquid does not contain corrosive chemicals and will not produce chemical reactions on metals; therefore, during the polishing process, it can be ensured that only the raised parts of the polishing surface are polished, and there is almost no height difference between the two materials after the polishing is completed; at the same time, since the surface is already in a relatively flat state during the fine polishing, the fine polishing only needs to maintain the consistency of the removal rates of the two materials to ensure that the height difference between the two materials in the final product reaches a very small level; and the time of chemical mechanical polishing is shortened, effectively reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of an existing chemical mechanical planarization polishing process; Figure 2 It is a measurement of the height difference between two materials after the existing chemical mechanical planarization polishing process; Figure 3 It is a measurement diagram of the height difference of the product surface after mechanical grinding and rough polishing of the present invention; Figure 4 is a measurement diagram of the height difference between two materials after chemical mechanical fine polishing of the present invention; Figure 5 It is a structural schematic diagram of the planarization polishing process of the present invention. DETAILED DESCRIPTION

[0015] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings: Example: Figure 5 As shown, a process for flattening the surface metal after filling the through-glass via process, the process steps are: S1. Mechanical grinding and rough polishing: Use a diamond grinding pad and 2μm aluminum oxide powder to mechanically grind and rough polish the metal on the surface of the product for a certain period of time to reduce the thickness of the metal on the surface of the product. The polishing time of this step is 15 to 30 minutes, and the removal amount is 10 to 20μm. The height difference of the product surface after polishing is less than 5nm. Figure 3 As shown; S2, chemical mechanical fine polishing: use 100nm silicon oxide polishing liquid, with polyurethane polishing pad for fine polishing, remove the remaining metal surface and improve the roughness, at the same time, according to the selection ratio of the two processing materials in the product, add a corresponding proportion of corrosive chemicals to react chemically with the metal to ensure that the removal rate of the two materials remains at a similar level. The polishing time of this step is 10 to 20 minutes, the removal amount is 5 to 10μm, and the height difference between the two materials on the surface of the polished product is less than 10nm. Figure 4 As shown. The metal on the surface of the product verified in the present invention is copper, and the substrate material of the product is glass. The added chemical agent is hydrogen peroxide. The ratio of the polishing liquid to the hydrogen peroxide is 100:7.5.

[0016] The present invention adds mechanical grinding and polishing before the existing chemical mechanical flattening polishing. The masonry grinding pad has high hardness and will not deform. The polishing liquid does not contain corrosive chemicals and will not produce chemical reactions on metals. Therefore, during the polishing process, it can be ensured that only the raised parts of the polishing surface are polished, and there is almost no height difference between the two materials after the polishing is completed. At the same time, since the surface is already in a relatively flat state during the fine polishing, the fine polishing only needs to maintain the consistency of the removal rates of the two materials to ensure that the height difference between the two materials in the final product reaches a very small level. In addition, the time of chemical mechanical polishing is shortened, effectively reducing the cost.

[0017] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. A process for flattening the surface metal after filling a through-glass via, characterized in that: The process steps are: S1. Mechanical grinding and rough polishing: Use a diamond grinding pad and 2μm alumina powder to mechanically grind and rough polish the metal on the surface of the product for a certain period of time to reduce the thickness of the metal on the surface of the product so that the height difference of the product surface after polishing is less than 5nm; S2. Chemical mechanical fine polishing: Use 100nm silicon oxide polishing liquid and polyurethane polishing pad for fine polishing to remove the remaining metal on the surface and improve the roughness. At the same time, according to the selection ratio of the two processing materials in the product, add a corresponding proportion of corrosive chemicals to react chemically with the metal to ensure that the removal rates of the two materials are kept at a similar level, so that the height difference between the two materials on the surface of the polished product is less than 10nm.

2. According to claim 1, the process for flattening the surface metal of a through-glass via after hole filling is characterized in that: In the step S1, the mechanical grinding and rough polishing takes 15-30 minutes.

3. The process for surface metal flattening after hole filling of a through glass via process according to claim 1, characterized in that: In the step S1, the thickness of the metal on the surface of the product is reduced to 10-20 μm.

4. The process for surface metal flattening after hole filling of through-glass via according to claim 1, characterized in that: In step S2, the chemical mechanical polishing time is 10 to 20 minutes.

5. The process for surface metal flattening after hole filling of through-glass via according to claim 1, characterized in that: In the step S2, the amount of removal of the product surface thickness is 5-10 μm.

6. The process for surface metal flattening after through-glass via filling according to claim 1, characterized in that: The metal on the surface of the product is copper, and the substrate material of the product is glass.

7. The process for planarizing the surface metal of a through-glass via after hole filling according to claim 1, characterized in that: In step S2, the added chemical agent is hydrogen peroxide.

8. The process for planarizing the surface metal of a through-glass via after hole filling according to claim 7, characterized in that: The ratio of the polishing liquid to hydrogen peroxide is 100:7.5.

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