Ceramic substrate with recessed structure and method of making the same

Abstract

The application discloses a ceramic substrate with a recess structure and a manufacturing method thereof, and relates to the technical field of ceramic substrate processing and manufacturing. The ceramic substrate with the recess structure comprises a ceramic substrate body and a recess structure arranged on a BGA packaging area of an upper surface of the ceramic substrate body. The recess structure comprises at least one recess body. An array of round holes is etched on an upper surface of the at least one recess body. The recess structure with different recess depths and roughness is manufactured on the BGA packaging area, so that the production efficiency is improved, the traditional multiple times of pattern transfer are reduced, the yield is improved, the cost is reduced, and the purpose of reducing the rejection rate is achieved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of ceramic substrate processing and manufacturing, and particularly relates to a ceramic substrate with a recess structure and a manufacturing method thereof. BACKGROUND

[0002] The ceramic substrate body plays an important role in the field of power electronic devices, and is usually composed of a ceramic layer and a metal layer bonded to the ceramic layer, and is a key element in the construction of electronic components, which can ensure the rapid dissipation of a large amount of heat during the operation of these components.

[0003] Considering the reliability, levelness and space utilization of high-density chip packaging, the metal (copper) surface of the ceramic substrate body manufactured by the AMB / DBC process needs to be designed with a recess structure.

[0004] At present, the ceramic substrate with a recess structure manufactured by the AMB / DBC process is usually manufactured by repeated pattern transfer, that is, the required pattern is first manufactured, and then the corresponding recess structure is manufactured according to the pattern. In the repeated pattern transfer manufacturing process, the sealing ability of the photosensitive dry film is not the same, and defects such as the occurrence of gaps in the pattern are prone to occur, resulting in low yield and production efficiency and high cost. SUMMARY

[0005] In view of the above defects, the embodiments of the present application provide a ceramic substrate with a recess structure and a manufacturing method thereof. The ceramic substrate with a recess structure and the manufacturing method thereof provided by the embodiments of the present application include the following technical solutions:

[0006] In a first aspect, the ceramic substrate with a recess structure provided by the embodiments of the present application includes:

[0007] a ceramic substrate body; and

[0008] a recess structure arranged on a BGA packaging area on an upper surface of the ceramic substrate body, wherein the recess structure includes at least one recess body, and an upper surface of the at least one recess body is etched with an array of circular holes.

[0009] In some examples, the recess structure includes at least two recess bodies, i.e., a first recess body and a second recess body, wherein the first recess body is etched with a first array of circular holes on the upper surface, and the second recess body is etched with a second array of circular holes on the upper surface.

[0010] A separation area is arranged between the first recess body and the second recess body as a safety distance compensation.

[0011] In some examples, the recess depth of the second recess body is greater than the recess depth of the first recess body.

[0012] In some examples, the diameter of each hole in the first circular hole array is smaller than the diameter of each hole in the second circular hole array.

[0013] In some examples, the number of holes in the first circular hole array is smaller than the number of holes in the second circular hole array.

[0014] In some examples, the area of the first circular hole array is 45-85% of the surface area of the first recess body.

[0015] In some examples, the area of the second circular hole array is 45-85% of the surface area of the second recess body.

[0016] In some examples, the thickness of the metal layer is 0.2-0.8 mm.

[0017] In a second aspect, the embodiments of the present application provide a method for manufacturing a ceramic substrate with a recess structure, which comprises the following steps:

[0018] A specific area of the copper-coated surface of the ceramic substrate body is used as a BGA packaging area;

[0019] A recess structure is manufactured in the BGA packaging area, wherein the recess structure comprises at least two recess bodies, and the recess structure is manufactured in the following manner:

[0020] Film pasting: a photosensitive dry film is hot-pressed and pasted on the upper surface of the ceramic substrate;

[0021] Exposure: a pre-prepared negative film pattern is used for exposure, so that the photosensitive dry film in the pattern part is subjected to photopolymerization;

[0022] Development: the photosensitive dry film in the non-pattern part and the BGA area are subjected to development operation with a developing solution;

[0023] Etching film removal: the non-pattern area and the BGA area without the protection of the photosensitive dry film are subjected to chemical etching operation, and the metal under the protection of the photosensitive dry film is reserved, so as to manufacture a circular hole array with different pitches and different diameters, and form a recess structure with at least two recess bodies with different recess depths.

[0024] In some examples, the thickness of the photosensitive dry film 5 is 20-50 μm.

[0025] Compared with the prior art, the ceramic substrate with a recess structure and the manufacturing method thereof provided by the embodiments of the present application have the following beneficial effects:

[0026] By making recessed structures with different recessed depths and roughness in the BGA packaging area, the required graphics and recessed structures can be made simultaneously at one time, which improves production efficiency, reduces the traditional process of multiple graphic transfers, improves the yield rate, reduces costs and increases efficiency, and achieves the goal of reducing scrap rate while reducing costs and increasing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic cross-sectional view of a ceramic substrate with a recessed structure provided by an embodiment of the present invention;

[0028] Figure 2 Another schematic cross-sectional view of a ceramic substrate with a recessed structure provided by an embodiment of the present invention;

[0029] Figure 3 A schematic diagram of the distribution shape of a circular hole array etched in a recessed structure of a ceramic substrate with a recessed structure provided in an embodiment of the present invention.

[0030] Notes:

[0031] 1. Ceramic substrate, 2. Metal layer, 3. First recessed body, 4. Second recessed body, 5. Photosensitive dry film, 6. First circular hole array, 7. Second circular hole array, 8. Isolation area.

[0032] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work. DETAILED DESCRIPTION

[0033] The following embodiments of the present disclosure are further described in detail with reference to the accompanying drawings and examples. The detailed description of the following examples and the accompanying drawings are intended to illustrate the principles of the present disclosure, but are not intended to limit the scope of the present disclosure. The present disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but rather includes all technical solutions within the scope of the claims.

[0034] Example 1

[0035] like Figure 1 As shown, the ceramic substrate with a recessed structure provided by an embodiment of the present invention includes:

[0036] A ceramic substrate body and a recessed structure arranged in the BGA packaging area on the upper surface of the ceramic substrate body, wherein the recessed structure at least includes a first recessed body 3 and a second recessed body 4, wherein the recessed depths of the first recessed body 3 and the second recessed body 4 are different.

[0037] Specifically, as shown in Figure 1 and Figure 2 The upper surface and the lower surface of the ceramic substrate 1 are both partially covered with metal (copper) to form a metal layer 2, and the ceramic substrate 1 and the metal layer 2 constitute the ceramic substrate body. On the surface of the metal layer 2, a photosensitive dry film 5 is covered.

[0038] In some examples, the thickness of the metal layer 2 is 0.2-0.8 mm. When the thickness of the metal layer 2 is 0.5-0.8 mm, a recess structure with at least 2 recesses can be made in the BGA packaging area.

[0039] As shown in Figure 3 , the upper surface of the first recess 3 is etched with a first circular hole array 6, and the upper surface of the second recess 4 is etched with a second circular hole array 7, wherein the hole diameter of each circular hole in the first circular hole array 6 is the same, and the hole diameter of each circular hole in the second circular hole array 7 is the same, so that the distribution of each circular hole etched on the upper surface of the first recess 3 and the second recess 4 is relatively uniform.

[0040] The isolation zone 8 is provided between the first recess 3 and the second recess 4, so that the boundary line between the first recess 3 and the second recess 4 serves as a safety distance compensation to avoid the first recess 3 and the second recess 4 from being connected together.

[0041] In some examples, as shown in Figure 2 , the recess depth of the second recess 4 is greater than that of the first recess 3, forming a continuous recess block in the BGA packaging area and the recess structure has a trend of gradually thinning edges, and the second recess 4 and the first recess 3 have a controllable difference in recess depth, which is beneficial to release the residual stress of the solder surface and improve the reliability of the chip packaging, without causing stress damage to the chip. At the same time, since the chip is fixed at the low position of the metal (copper) layer and has the same recess depth as the high position metal (copper) layer, the space utilization of the BGA packaging area is improved.

[0042] In some examples, the hole diameter of each circular hole in the first circular hole array 6 is smaller than the hole diameter of each circular hole in the second circular hole array 7, and the number of each circular hole in the first circular hole array 6 is smaller than the number of each circular hole in the second circular hole array 7, so that the surface of the first recess 3 and the second recess 4 has a controllable roughness.

[0043] In some examples, the area occupied by the first circular hole array 6 is 45-85% of the area of the upper surface of the first recess 3.

[0044] In some examples, the area occupied by the second circular hole array 7 is 45-85% of the area of the upper surface of the second recess 4.

[0045] Embodiment 2

[0046] The method for manufacturing the ceramic substrate with the recess structure comprises the following steps:

[0047] S1, taking a specific area on the copper-coated upper surface of the ceramic substrate body as a BGA packaging area;

[0048] S2, manufacturing a recess structure in the BGA packaging area, wherein the recess structure comprises at least two recess bodies, and the manufacturing process of the recess structure is as follows:

[0049] Film pasting: pasting the photosensitive dry film 5 on the upper surface of the ceramic substrate body.

[0050] Specifically, the thickness of the photosensitive dry film 5 used in the film pasting process is 20-50 μm.

[0051] Exposure: exposing using a pre-drawn negative film pattern to cause the photosensitive dry film in the pattern part to undergo photopolymerization.

[0052] Specifically, the exposure energy used in the exposure process is 55-100 mJ / cm 2 , and the exposure energy test scale is 6-8 grids.

[0053] Development: developing the non-pattern part of the photosensitive dry film 5 and the BGA area with a developing solution.

[0054] Specifically, the developing solution concentration is 8-12 g / L, and the upper and lower spraying pressure is 1.0-2.0 kg / cm 2 .

[0055] Etching film removal: performing chemical etching on the non-pattern area and the BGA area without the protection of the photosensitive dry film 5 and retaining the metal layer 2 under the protection of the photosensitive dry film to manufacture a circular hole array with different pitches and different hole diameters, and form a recess structure with at least two recess bodies with different recess depths.

[0056] In particular, in the case where the recess structure has only one recess body, only a circular hole array with the same pitch and the same hole diameter needs to be manufactured in the process of etching film removal.

[0057] In some examples, the thickness of the photosensitive dry film 5 is 20-50 μm.

[0058] Specifically, when the thickness of the metal layer 2 is 0.20-0.25 mm, the hole diameter of each circular hole in the BGA packaging area is 0.025-0.07 mm, the hole wall size is 0.03-0.05 mm, the surface roughness Ra of the recessed structure is 10-15 μm, and the recessed depth is 0.1-0.15 mm (based on the upper surface of the metal layer 2); when the thickness of the metal layer 5 is 0.30 mm, the hole diameter of each circular hole in the BGA packaging area is 0.06-0.10 mm, the hole wall size is 0.06-0.09 mm, the surface roughness Ra of the recessed structure is 12-25 μm, and the recessed depth is 0.17-0.23 mm (based on the upper surface of the metal layer 2); when the thickness of the metal layer 2 is 0.40 mm, the hole diameter of each circular hole in the BGA packaging area is 0.08-0.125 mm, the hole wall size is 0.08-0.10 mm, the surface roughness Ra of the recessed structure is 20-30 μm, and the recessed depth is 0.2-0.3 mm (based on the metal layer 2); when the thickness of the metal layer 2 is 0.5-0.8 mm, a recessed structure with at least two recessed bodies can be designed, the hole diameter of the BGA packaging area is designed to be 0.025-0.125 mm, the hole wall size is 0.03-0.13 mm, the block interval isolation area width is 0.05-0.125 mm, the surface roughness Ra of each recessed body is 10-30 μm, and the recessed depth is 0.1-0.3 mm (based on the upper surface of the metal layer 2).

[0059] It should be noted that the present application is not limited to the specific configurations and processes described above and shown in the drawings. For the sake of brevity, the detailed description of known methods is omitted herein. In the above-described embodiments, several specific steps are described and shown as examples. However, the method processes of the present application are not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order of the steps, after understanding the spirit of the present application.

[0060] In addition, the "first", "second" and similar words used in the present disclosure do not represent any order, quantity or importance, but are only used to distinguish different parts.

[0061] The above describes only the specific implementation of the present application, and those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described system, module and unit can refer to the corresponding process in the foregoing method embodiments, which will not be described here. It should be understood that the protection scope of the present application is not limited thereto, and any skilled person in the art can easily think of various equivalent modifications or replacements within the technical range disclosed by the present application, and these modifications or replacements shall be covered within the protection scope of the present application.

Claims

1. A ceramic substrate having a recessed structure, characterized by, The application relates to a ceramic substrate body and a recess structure arranged on a BGA packaging area on the upper surface of the ceramic substrate body. The application relates to a ceramic substrate body and a recess structure arranged on a BGA packaging area on the upper surface of the ceramic substrate body. The upper surface of at least one of the recess bodies is etched with an array of circular holes. The recess structure comprises at least two recess bodies, i.e. a first recess body and a second recess body. The first recess body is provided with a first array of circular holes on the upper surface, and the second recess body is provided with a second array of circular holes on the upper surface. The first array of circular holes and the second array of circular holes are arranged on the upper surface of the first recess body. The first array of circular holes and the second array of circular holes are arranged on the upper surface of the first recess body. The first array of circular holes and the second array of circular holes are arranged on the upper surface of the first recess body.

2. The ceramic substrate having a recessed structure according to claim 1, characterized by, The first array of circular holes and the second array of circular holes are arranged on the upper surface of the first recess body.

3. The ceramic substrate having a recessed structure according to claim 1, characterized by, The first array of circular holes and the second array of circular holes are arranged on the upper surface of the first recess body.

4. The ceramic substrate having a recessed structure according to claim 1, characterized by, The first array of circular holes and the second array of circular holes are arranged on the upper surface of the first recess body.

5. The ceramic substrate having a recessed structure according to claim 1, characterized by, The first array of circular holes and the second array of circular holes are arranged on the upper surface of the first recess body.

6. The ceramic substrate having a recessed structure according to claim 1, characterized by, The first array of circular holes and the second array of circular holes are arranged on the upper surface of the first recess body.

7. A method for producing a ceramic substrate having a recessed structure according to any one of claims 1 to 6, characterized by, The first array of circular holes and the second array of circular holes are arranged on the upper surface of the first recess body. The first array of circular holes and the second array of circular holes are arranged on the upper surface of the first recess body. The first array of circular holes and the second array of circular holes are arranged on the upper surface of the first recess body. The first array of circular holes and the second array of circular holes are arranged on the upper surface of the first recess body. The first array of circular holes and the second array of circular holes are arranged on the upper surface of the first recess body. The first array of circular holes and the second array of circular holes are arranged on the upper surface of the first recess body. The first array of circular holes and the second array of circular holes are arranged on the upper surface of the first recess body.

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