A copper clad ceramic substrate structure

Abstract

The application relates to the technical field of semiconductor substrates, and particularly relates to a copper-clad ceramic substrate structure, which comprises a substrate body, a front copper layer and a plastic sealing layer, the front copper layer is fixedly installed on one side of the substrate body, the plastic sealing layer is plastic-sealed on the outer surface of the front copper layer, the substrate body is provided with an outer connecting sheet, the outer connecting sheet comprises an upper horizontal section, a vertical section and a lower horizontal section, the upper horizontal section is used for connecting external electrical elements, the lower horizontal section is fixedly connected with a thick copper area of the front copper layer, the vertical section is located between the upper horizontal section and the lower horizontal section and penetrates through a window of the plastic sealing layer, and the outer connecting sheet is positioned and matched at the bending positions of the upper horizontal section and the vertical section and the edge of the window. The upper horizontal section, the vertical section and the lower horizontal section of the application are collectively positioned and matched with the plastic sealing layer and the thick copper area, so that the displacement of the outer connecting sheet in the welding process is effectively limited.

Description

Technical Field

[0001] This application relates to the technical field of semiconductor substrates, and in particular to a copper-clad ceramic substrate structure. Background Technology

[0002] Copper-clad ceramic substrate is an electronic packaging carrier composed of a copper layer and a ceramic layer. Specifically, it includes a front copper layer, a ceramic substrate layer, and a back copper layer. The front copper layer is responsible for component soldering, circuit wiring, and current carrying. The ceramic substrate layer provides insulation support and efficient heat dissipation. The back copper layer assists in heat dissipation and is connected to an external heat dissipation structure. The three work together to achieve electrical conduction, insulation isolation, and thermal management functions.

[0003] To meet different functional requirements, the front copper layer includes a thick copper area and a thin copper area. The thick copper area is used to support component soldering and high-current conductive paths, while the thin copper area is used for precision circuit wiring. To isolate the front copper layer from other external components and avoid short circuits or leakage caused by direct contact, a molding compound is usually placed on the front copper layer as a molding compound. This molding compound is injection molded and covers the surface of the front copper layer. If the molding compound is placed first, an opening needs to be made in the thick copper area to be soldered to form an opening. The opening on the molding compound is used to expose the thick copper area so that the thick copper area can be soldered to external electrical components.

[0004] The electrical connection between the substrate and external electrical components often uses copper sheets as the conductive medium. The soldering position of the substrate is located in the thick copper area after the windowing treatment. Due to the height difference between the soldering position of the molding compound and the thick copper area, the copper sheet needs to be designed as a bent structure to overcome the thickness of the molding compound. Most existing copper sheets adopt an integrated irregular structure and lack a precise positioning structure, which makes it easy to shift during soldering and affect the soldering accuracy between the copper sheet and the thick copper area and external electrical components.

[0005] Therefore, a copper-clad ceramic substrate structure is needed to solve the problem that copper sheets are prone to displacement, which leads to the easy misalignment of the welding positions between the copper sheets and the thick copper area and external electrical components. Summary of the Invention

[0006] In order to achieve the positioning and matching of the copper sheet and the molding layer, and to achieve the precise positioning of the bent copper sheet, the thick copper area, and external electrical components, this application provides a copper-clad ceramic substrate structure.

[0007] This application provides a copper-clad ceramic substrate structure, which adopts the following technical solution: A copper-clad ceramic substrate structure includes a substrate body with a front copper layer and a molding compound layer. The front copper layer is fixedly mounted on one side of the substrate body, and the molding compound layer is molded onto the outer surface of the front copper layer. The substrate body is provided with an external connecting piece, which includes an upper horizontal section, a vertical section, and a lower horizontal section. The upper horizontal section is used to connect external electrical components, and the lower horizontal section is fixedly connected to the thick copper area of ​​the front copper layer. The vertical section is located between the upper and lower horizontal sections and passes through an opening in the molding compound layer. The external connecting piece is positioned and fitted at the bend between the upper and vertical sections and at the edge of the opening. The external connecting piece is also positioned and fitted at the bend between the vertical and lower horizontal sections, the surface of the thick copper area, and the inner side of the opening.

[0008] By adopting the above technical solution, the bending points of the upper horizontal and vertical sections, and the bending points of the vertical and lower horizontal sections, achieve multi-directional positioning and cooperation with the molding layer and thick copper area, effectively limiting the displacement of the external connecting piece during the welding process, ensuring that the welding positions of the external connecting piece and the thick copper area and external electrical components are accurately aligned, and improving the connection reliability and electrical conductivity stability.

[0009] Optionally, the thickness of the upper horizontal segment is greater than the thickness of the lower horizontal segment to enhance the connection strength between the upper horizontal segment and external electrical components.

[0010] By adopting the above technical solution, the upper transverse section is located on the surface of the plastic sealant, which is easily subjected to external forces. While ensuring conductivity, it improves the mechanical strength when connected to external electrical components.

[0011] Optionally, the front copper layer includes a thin copper region, the thickness of which is less than the thickness of the thick copper region, and the thin copper region has an etching groove for laying circuits.

[0012] By adopting the above technical solution, the thickness of the thin copper area is smaller, the precision of etching circuits on the thin copper area is higher, the opening of the etched trench is narrower and the edge is clearer, which is conducive to realizing high-density circuit layout and fine circuit design, and improving the overall electrical performance and signal transmission efficiency of the substrate.

[0013] Optionally, a thickening layer is fixedly connected to the bottom of the upper horizontal section, and the thickening layer is located outside the plastic sealant layer.

[0014] By adopting the above technical solution, the thickness of the upper horizontal section outside the plastic seal layer is further increased, which enhances the bending resistance of the upper horizontal section outside the plastic seal layer and enhances the bonding strength and stability when welding with external electrical components.

[0015] Optionally, the vertical section, the upper horizontal section, and the thickened layer together form a limiting groove, and the sidewall of the limiting groove abuts against the outer side of the plastic sealing layer.

[0016] By adopting the above technical solution, the sidewall of the limiting groove abuts against the outer side of the plastic sealing layer, effectively preventing the outer connecting piece from shifting during the welding process, and further improving the positioning accuracy and connection stability.

[0017] Optionally, the connection between the upper horizontal segment and the vertical segment, and the connection between the vertical segment and the lower horizontal segment, are provided with rounded corner transition structures.

[0018] By adopting the above technical solution, the rounded corner transition structure can effectively reduce the stress concentration at the bending point of the outer connecting piece, prevent material fatigue cracking caused by sharp corners, improve the overall mechanical reliability and service life of the outer connecting piece, and at the same time, the rounded corner transition structure facilitates the smooth entry of the outer connecting piece into the window during the assembly process, avoiding damage to the plastic sealant or assembly failure caused by sharp corner jamming.

[0019] Optionally, the inner wall of the window is provided with a guide slope, which is used to guide the outer connecting piece to be inserted into the window.

[0020] By adopting the above technical solution, the guide bevel can provide effective guidance when the outer connecting piece is inserted into the window, reduce the difficulty of alignment during the assembly process, and avoid insertion obstruction or damage to the edge of the plastic sealant due to angular deviation.

[0021] Optionally, the molding layer is provided with abutting protrusions, and the inner wall of the limiting groove is provided with positioning grooves that cooperate with the abutting protrusions.

[0022] By adopting the above technical solution, the cooperation between the anti-protrusion and the positioning groove forms multiple positioning of the external connecting piece, further enhancing the positional accuracy of the external connecting piece.

[0023] In summary, this application includes at least one of the following beneficial technical effects: 1. The bending points between the upper horizontal and vertical sections, and between the vertical and lower horizontal sections, achieve multi-directional positioning and fit with the molding layer and thick copper area, effectively avoiding the offset of the external connecting piece during the welding process, and ensuring the connection accuracy and reliability of the external connecting piece with the thick copper area and external electrical components. 2. The thin copper area has a smaller thickness, which allows for higher precision when etching circuits on the thin copper area. The resulting etching trench has a narrower opening and clearer edges, which is conducive to achieving high-density circuit layout and fine circuit design, and improves the overall electrical performance and signal transmission efficiency of the substrate. 3. The rounded corner transition structure can effectively reduce stress concentration at the bending point of the outer connecting piece, prevent material fatigue cracking caused by sharp corners, improve the overall mechanical reliability and service life of the outer connecting piece, and at the same time, the rounded corner transition structure facilitates the smooth entry of the outer connecting piece into the opening during the assembly process, avoiding damage to the plastic sealant or assembly failure caused by sharp corner jamming. Attached Figure Description

[0024] Figure 1 This is a cross-sectional view of Embodiment 1 of this application, used to show the overall structure of the substrate; Figure 2 This is a partial cross-sectional view of Embodiment 1 of this application, used to show the specific structure of the outer connecting piece; Figure 3 This is a partial cross-sectional view of Embodiment 2 of this application, used to show the placement of the guide ramp and the thickened layer.

[0025] Reference numerals: 1. Substrate; 111. Front copper layer; 112. Thick copper area; 113. Thin copper area; 114. Etching groove; 121. Back copper layer; 131. Ceramic layer; 2. Molding layer; 211. Window; 212. Abutting protrusion; 213. Guide slope; 3. External connecting piece; 311. Upper horizontal section; 312. Thickened layer; 321. Vertical section; 331. Lower horizontal section; 4. Positioning groove; 5. Limiting groove. Detailed Implementation

[0026] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0027] Example 1: A copper-clad ceramic substrate structure, reference Figure 1 and Figure 2The system includes a substrate 1, with a front copper layer 111 on the front side and a back copper layer 121 on the back side. A ceramic layer 131 is installed between the front copper layer 111 and the back copper layer 121. The front copper layer 111 includes a thick copper area 112, and a molding compound 2 is encapsulated on the thick copper area 112. The molding compound 2 has a window 211 in the area of ​​the thick copper area 112 that needs to be soldered, which is used to expose the thick copper area 112 so as to enable soldering with external electrical components. The substrate 1 also has an external connecting piece 3. In this embodiment, the external connecting piece 3 is a copper sheet. The external connecting piece 3 includes an upper horizontal section 311, a vertical section 321, and a lower horizontal section 331. The upper horizontal section 311, the vertical section 321, and the lower horizontal section 331 are integrally formed to form a Z-shaped structure. The lower horizontal section 331 is soldered and fixed to the exposed thick copper area 112. The vertical section 321 extends from the end of the lower horizontal section 331. The upper horizontal section 311 bends upward and extends from the opening 211 of the molding layer 2 to the upper surface of the molding layer 2. The upper horizontal section 311 extends horizontally outward from the top of the vertical section 321. The end of the upper horizontal section 311 is used for welding with external electrical components to realize the circuit connection between the ceramic substrate and the external electrical components. The upper horizontal section 311 and the vertical section 321 are perpendicular to each other. The bending structure formed by the upper horizontal section 311 and the vertical section 321 is adapted to the edge shape of the opening 211. The lower horizontal section 331 is perpendicular to the vertical section 321. The bending structure formed by the lower horizontal section 331 and the vertical section 321 is positioned and fitted with the inner side of the opening 211 and the surface of the thick copper area 112, so as to accurately define the position of the external connecting piece 3. Through the coordinated positioning of the three structures of the upper horizontal section 311, the vertical section 321 and the lower horizontal section 331, the displacement and skewness of the external connecting piece 3 during the welding process are effectively suppressed.

[0028] refer to Figure 1 and Figure 2 The openings 211 of the molding compound 2 can be set individually or in parallel according to welding requirements. There are three forms of openings 211: First, the openings 211 of the molding compound 2 are the same size as the thick copper area 112, and the welding area matches the thick copper area 112. Strict control of processing accuracy is required to avoid deviation of the openings 211 that would result in incomplete exposure of the thick copper area 112. Second, the openings 211 of the molding compound 2 are slightly larger than the thick copper area 112, which exposes part of the thin copper area 113. The exposed thin copper area 113 is at risk of oxidation. Third, the openings 211 of the molding compound 2 are smaller than the thick copper area 112, exposing only the part of the thick copper area 112 in the middle for welding. The molding compound 2 effectively covers the edge of the thick copper area 112, reducing the risk of copper oxidation. This embodiment adopts the third form of opening 211, that is, the openings 211 of the molding compound 2 are smaller than the thick copper area 112.

[0029] refer to Figure 1 and Figure 2In this embodiment, the ceramic layer 131 is made of aluminum nitride material with a thickness between 0.2 mm and 0.5 mm. It has excellent thermal conductivity and insulation properties. The ceramic layer 131 is sintered with the front copper layer 111 and the back copper layer 121 using brazing filler to form a firm connection.

[0030] refer to Figure 1 and Figure 2 The front copper layer 111 also includes a thin copper area 113, which is formed by the front copper layer 111 through a semi-etching process. The semi-etching process only removes part of the thickness of the front copper layer 111. The area of ​​the front copper layer 111 that is not semi-etched is the thick copper area 112. The thickness of the thick copper area 112 is greater than the thickness of the thin copper area 113. The thickness of the thin copper area 113 is greater than the thickness of the back copper layer 121. The thick copper area 112 has a large thickness, which can carry a large current and meet the welding requirements. The thick copper area 112 can also serve as a signal transmission channel, providing stable electrical connection and signal conduction for components such as AMB.

[0031] refer to Figure 1 and Figure 2 The thin copper area 113 is etched into an etching trench 114 through a secondary etching process. The etching trench 114 penetrates the front copper layer 111 and exposes the surface of the ceramic layer 131. It is used to isolate the circuit and achieve insulation between different circuit areas. Since the thin copper area 113 is thin, under the lateral etching effect, the etching solution takes less time to reach the ceramic layer 131 in the longitudinal direction. The lateral etching range is limited, so the width of the etch trench 114 is small, which makes the front copper layer 111 have a high space utilization rate and wiring density.

[0032] refer to Figure 1 and Figure 2 The lower horizontal section 331 is located inside the window 211 of the plastic seal layer 2 and is welded and fixed to the thick copper area 112, making it less susceptible to external forces. The upper horizontal section 311 is exposed on the outer surface of the plastic seal layer 2, making it more susceptible to deformation under external pressure. The thickness of the upper horizontal section 311 is greater than that of the lower horizontal section 331, thereby enhancing the structural rigidity and strength of the upper horizontal section 311 and effectively resisting external impacts.

[0033] The implementation principle of Embodiment 1 of this application is as follows: the copper layer 111 on the front side of the copper-clad ceramic substrate is partially etched to form a thick copper area 112 and a thin copper area 113. The thick copper area 112 carries a large current, meets the welding requirements, and transmits signals. The thin copper area 113 is etched twice to form an etching groove 114 to achieve circuit isolation. The Z-shaped structure of the external connecting piece 3 includes an upper horizontal section 311, a vertical section 321, and a lower horizontal section 331. The upper horizontal section 311, the vertical section 321, and the lower horizontal section 331 work together with the window 211 and the thick copper area 112 to achieve precise alignment and reliable connection of the external connecting piece 3 between the substrate structure and external electrical components.

[0034] Example 2: A copper-clad ceramic substrate structure, reference Figure 3 The difference from Embodiment 1 is that the connection between the upper horizontal section 311 and the vertical section 321 of the outer connecting piece 3 and the connection between the vertical section 321 and the lower horizontal section 331 are provided with rounded corner transition structures. The rounded corner transition structures can effectively reduce stress concentration at the bending point of the outer connecting piece 3, improve the mechanical strength and fatigue resistance of the outer connecting piece 3 structure, and reduce the risk of fracture.

[0035] refer to Figure 3 The end of the upper horizontal section 311 extends a distance outward from the edge of the plastic seal layer 2 to facilitate welding with external electrical components. In this extended area, the upper horizontal section 311 is integrally formed with a thickened layer 312. The side of the thickened layer 312 abuts against the side wall of the plastic seal layer 2, which improves the stability of the upper horizontal section 311 during welding. The thickened layer 312, the upper horizontal section 311, and the vertical section 321 together form a limiting groove 5. The side wall of the limiting groove 5 abuts against the outer side of the plastic seal layer 2, which further improves the positioning accuracy of the outer connecting piece 3.

[0036] refer to Figure 3 The surface of the plastic seal 2 facing the upper horizontal section 311 is integrally formed with abutting protrusion 212. The inner wall of the limiting groove 5 is provided with a positioning groove 4 that matches the shape of the abutting protrusion 212. The abutting protrusion 212 is located in the positioning groove 4, which further enhances the positioning accuracy of the outer connecting piece 3. The opening of the window 211 is provided with a guide slope 213. The guide slope 213 facilitates the smooth insertion of the outer connecting piece 3 during the assembly process and avoids structural damage caused by misalignment.

[0037] The implementation principle of Embodiment 2 of this application is as follows: a rounded transition structure is set at the connection between the upper horizontal section 311 and the vertical section 321, and between the vertical section 321 and the lower horizontal section 331. By dispersing the stress concentration at the bending point, fatigue wear during long-term use is reduced. The thickened layer 312 provides stable support for welding with external electrical components and, together with the vertical section 321 and the upper horizontal section 311, forms a limiting groove 5, which is adapted to the surface of the plastic sealing layer 2 to achieve precise positioning of the external connecting piece 3. The guide slope 213 at the opening 211 ensures the smooth introduction of the external connecting piece 3 during the assembly process, further improving the reliability of the structural assembly and the stability of use.

[0038] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A copper-clad ceramic substrate structure, comprising a substrate body (1), wherein the substrate body (1) is provided with a front copper layer (111) and a molding compound (2), the front copper layer (111) is fixedly mounted on one side of the substrate body (1), the molding compound (2) is molded onto the outer surface of the front copper layer (111), and the substrate body (1) is provided with an external connecting piece (3), characterized in that: The external connecting piece (3) includes an upper horizontal section (311), a vertical section (321), and a lower horizontal section (331). The upper horizontal section (311) is used to connect external electrical components. The lower horizontal section (331) is fixedly connected to the thick copper area (112) of the front copper layer (111). The vertical section (321) is located between the upper horizontal section (311) and the lower horizontal section (331) and passes through the opening (211) of the plastic seal layer (2). The external connecting piece (3) is positioned and fitted at the bend of the upper horizontal section (311) and the vertical section (321) and the edge of the opening (211). The external connecting piece (3) is positioned and fitted at the bend of the vertical section (321) and the lower horizontal section (331), the surface of the thick copper area (112), and the inner side of the opening (211).

2. The copper-clad ceramic substrate structure according to claim 1, characterized in that: The thickness of the upper horizontal section (311) is greater than the thickness of the lower horizontal section (331) to enhance the connection strength between the upper horizontal section (311) and external electrical components.

3. The copper-clad ceramic substrate structure according to claim 1, characterized in that: The front copper layer (111) includes a thin copper area (113), the thickness of which is less than the thickness of the thick copper area (112), and the thin copper area (113) has an etching groove (114) for laying circuits.

4. The copper-clad ceramic substrate structure according to claim 1, characterized in that: The bottom of the upper horizontal section (311) is fixedly connected to a thickened layer (312), which is located outside the plastic sealant layer (2).

5. The copper-clad ceramic substrate structure according to claim 4, characterized in that: The vertical section (321), the upper horizontal section (311), and the thickened layer (312) together form a limiting groove (5), and the side wall of the limiting groove (5) abuts against the outer side of the plastic sealing layer (2).

6. The copper-clad ceramic substrate structure according to claim 1, characterized in that: The connection between the upper horizontal segment (311) and the vertical segment (321), and the connection between the vertical segment (321) and the lower horizontal segment (331) are provided with rounded corner transition structures.

7. The copper-clad ceramic substrate structure according to claim 1, characterized in that: The inner wall of the opening (211) is provided with a guide slope (213), which is used to guide the outer connecting piece (3) to be inserted into the opening (211).

8. The copper-clad ceramic substrate structure according to claim 5, characterized in that: The encapsulation layer (2) is provided with abutting protrusions (212), and the inner wall of the limiting groove (5) is provided with positioning grooves (4) that are positioned and matched with the abutting protrusions (212).

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