Packaging structure design and packaging process of multi-channel driving circuit

Abstract

The invention discloses a packaging structure design and a packaging process of a multi-channel driving circuit, and relates to the technical field of microelectronic device packaging. Which comprises a ceramic base, a metal wall, a chip carrier and an outer lead electrode, and is characterized in that the ceramic base is of a stepped structure and is made of an Al2O3 multilayer ceramic material; the metal wall on the first step is fixedly connected with the ceramic base through a sintering process, and nine inner electrode bonding pads are arranged on the second step; the chip carrier on the third step is fixedly connected with the ceramic base through a sintering process; and an outer lead electrode is welded and fixed at the bottom of the ceramic base. The heat conductivity of the ceramic material is obviously higher than that of the plastic packaging material, heat generated by the chip can be efficiently conducted to the external environment, and a lighter and smaller packaging appearance is achieved through internal structure optimization. And secondly, the loss of the high-frequency signal in the ceramic material is lower, so that the loss of a finished product device can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microelectronic device packaging, in particular to a packaging structure design and packaging process of a multi-channel drive circuit. BACKGROUND

[0002] The existing plastic packaging SOP-8 and DFN4x4-8 packaging structures cannot provide better heat dissipation performance due to the poor thermal conductivity of plastic materials, and need to be built-in with heat dissipation fins and heat conduction channels. However, under the condition of optimizing the heat conduction performance, the built-in heat dissipation fins and channels lead to an increase in the size and weight of the plastic packaging structure device. Secondly, plastic packaging products have poor environmental stress resistance and low reliability. At present, the products in the field of microelectronic packaging are developing towards lightness and miniaturization, and at the same time, the high-end fields such as military, aerospace electronics, medical treatment, and automobile power modules are realizing localization substitution, and the market has put forward the demand for high reliability, lighter and smaller packaging structures for such products.

[0003] The present application comprehensively considers the internal circuit structure, product reliability, and product typical application scenarios such as military and aerospace electronics to design the packaging structure. In other performance aspects, the present application utilizes the structural characteristics of ceramic materials to have better mechanical strength, air tightness, and environmental stress resistance, etc. While meeting the miniaturization and small size of the device, the present application provides higher reliability. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a patch ceramic structure package that can be used for packaging, aiming at the defects of large volume, high loss, and low environmental stress resistance of plastic packaging devices.

[0005] To this end, the present application provides a multi-channel drive circuit packaging method, comprising the following methods: (1) A ceramic base, a metal wall, a chip carrier, and an external lead electrode are welded to form a ceramic packaging shell.

[0006] (2) The ceramic base adopts a stepped structure design, the first step is sintered with a shell seal, the second step is made with a plurality of internal electrode pads according to the circuit structure, which are used as internal bonding areas, and the third step is sintered with a chip carrier; the bottom of the ceramic base is made with a plurality of external lead electrode pins according to the circuit structure. The ceramic base material adopts Al2O3 multilayer ceramic, and the thermal conductivity of the ceramic material is significantly higher than that of the plastic packaging material, which can efficiently conduct the heat generated by the chip to the external environment, and through internal structure optimization, a lighter and smaller packaging shape is realized. Secondly, the loss of high-frequency signals in the ceramic material is lower, effectively reducing the loss of the packaged product.

[0007] (3) The inner electrode pad adopts a Ni-Au composite metal structure, and the surface layer is gold. The inner electrode pad is connected to the outer lead electrode through a metal (such as tungsten) with high strength stability and low impedance. The internal circuit structure is connected to the shell electrode through a metal via hole, and has the effects of high mechanical strength and low parasitic impedance.

[0008] (4) The metal wall material adopts Kovar ring 4J29 alloy. The coefficient of thermal expansion (CTE) is close to that of the ceramic base, the internal stress is small when welded as a whole, and deformation cracking is not easy to occur. The mechanical strength and air tightness of the ceramic shell as a whole are improved, and the air leakage rate is ≤1×10 -3 Pa·cm 3 / s.

[0009] (5) The chip carrier adopts WCu15 alloy material, and the surface layer is plated with gold. It is used to fix the position of the chip during sintering, improve the yield, and increase the heat capacity of the device and improve the power of the device.

[0010] (6) The surface of the outer lead electrode at the bottom of the shell is treated by gold plating, so that the outer lead electrode is easy to weld and not easy to oxidize, and has good stability. The connection with the inner electrode pad is completed through a tungsten slurry metal via hole transmission line.

[0011] The packaging structure of the multi-channel drive circuit packaging method is shown in Figures 1-3 . It is composed of a ceramic base, a metal wall, a chip carrier, and an outer lead electrode.

[0012] The ceramic base is a stepped structure, and the ceramic base is an Al2O3 multilayer ceramic material; the metal wall on the first step is fixedly connected with the ceramic base through a sintering process, nine inner electrode pads are arranged on the second step; the chip carrier on the third step is fixedly connected with the ceramic base through a sintering process; and the outer lead electrode is fixedly welded at the bottom of the ceramic base.

[0013] The metal wall is fixedly connected with the ceramic base through a sintering process to form a cavity.

[0014] The inner electrode pad is a Ni-Au structure, and a metal coating is arranged on the surface.

[0015] The outer lead electrode is fixedly welded at the bottom of the ceramic base, and a metal coating is arranged on the surface layer.

[0016] The inner electrode pad is a bonding area and is connected with the outer lead electrode through a tungsten slurry metal via hole.

[0017] The metal wall material is Kovar ring 4J29 alloy.

[0018] The chip carrier is WCu15 alloy material, and a metal coating is arranged on the surface layer. The chip carrier has no electrical characteristics.

[0019] The ceramic base bottom end is provided with a part sealing frame, and has no electrical characteristics.

[0020] The surface of the part sealing frame is provided with a metal coating.

[0021] The beneficial effects of the present application are that the product size is as small as possible, higher mechanical strength, environmental stress resistance and power density are provided, the packaging category of this type of driver is widened, it can be applied to high reliability environments, and it provides the possibility of opening the high-end product market for this type of product. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a cross-sectional structure schematic diagram of the inner cavity of the present application.

[0023] Figure 2 It is a top view structure schematic diagram of the present application.

[0024] Figure 3 It is a bottom view structure schematic diagram of the present application.

[0025] In the figure: 1 is an external lead electrode, 2 is an external lead electrode, 3 is an external lead electrode, 4 is an external lead electrode, 5 is an external lead electrode, 6 is an external lead electrode, 7 is an external lead electrode, 8 is an external lead electrode, 9 is a metal wall, 10 is a ceramic base, 11 is an internal electrode pad, 21 is an internal electrode pad, 31 is an internal electrode pad, 32 is an internal electrode pad, 41 is an internal electrode pad, 51 is an internal electrode pad, 61 is an internal electrode pad, 71 is an internal electrode pad, 81 is an internal electrode pad, 101 is a third step, 102 is a second step, 103 is a chip carrier, and 104 is a part sealing frame. DETAILED DESCRIPTION

[0026] The following embodiments are proposed for the packaging structure design and packaging process of the multi-channel drive circuit: As Figures 1-3 shown, the present application provides a packaging structure design and packaging process of a multi-channel drive circuit, which comprises: The ceramic base 10, the metal wall 9, the chip carrier 101, the external lead electrodes 1, 2, 3, 4, 5, 6, 7, and 8 are composed. Preferably, the ceramic base 10 and the metal wall 9 form an outer shell of the packaging structure, and the outer shell size is 6.00mmx5.00mmx2.15mm.

[0027] The ceramic base 10 is a stepped structure, and the ceramic base 10 is an Al2O3 multilayer ceramic material; the first stepped metal wall 9 is fixedly connected with the ceramic base 10 through a sintering process, nine inner electrode pads 11, 21, 31, 32, 41, 51, 61, 71 and 81 are arranged on the second stepped 102; the chip carrier 103 on the third stepped 101 is fixedly connected with the ceramic base 10 through a sintering process; and the outer lead electrodes 1, 2, 3, 4, 5, 6, 7 and 8 are fixedly welded on the bottom of the ceramic base 10. Preferably, the sizes of the outer lead electrodes 1, 2, 3, 4, 5, 6, 7 and 8 are all 1.42mmx0.60mm, and the interval is 1.27mm; and the chip carrier 103 is fixedly connected at the center position of the third stepped 101.

[0028] The metal wall 9 is fixedly connected with the ceramic base 10 through a sintering process to form a cavity, and preferably, the inner size of the cavity is 4.40mmx3.40mmx0.60mm.

[0029] The inner electrode pads 11, 21, 31, 32, 41, 51, 61, 71 and 81 are of Ni-Au structure and are provided with a metal coating on the surface. The nine inner electrode pads 11, 21, 31, 32, 41, 51, 61, 71 and 81 are wire bonding areas for interconnection of the chip and the tube shell.

[0030] The outer lead electrodes 1, 2, 3, 4, 5, 6, 7 and 8 fixedly welded on the bottom of the ceramic base 10 are provided with a metal coating on the surface.

[0031] The inner electrode pads 11, 21, 31, 32, 41, 51, 61, 71 and 81 are bonding areas and are connected with the outer lead electrodes 1, 2, 3, 4, 5, 6, 7 and 8 through tungsten paste metal vias. Preferably, the interconnection relationship between the inner electrode pads and the outer lead electrodes is as follows: (1)-(11), (2)-(21), (3)-(31)-(32), (4)-(41), (5)-(51), (6)-(61), (7)-(71) and (8)-(81).

[0032] The material of the metal wall 9 is Kovar 4J29 alloy.

[0033] The chip carrier 103 is of WCu15 alloy material and is provided with a metal coating on the surface. The chip carrier 103 has no electrical characteristics. Preferably, the size of the chip carrier 103 is 1.70mmx1.50mmx0.20mm.

[0034] One end of the bottom of the ceramic base 10 is provided with a part sealing frame which has no electrical characteristics.

[0035] The surface of the part sealing frame 104 is provided with a metal coating.

[0036] Preferably, the ceramic base 10 is made of 95% Al2O3 multilayer ceramic, and the metal wall 9 is made of Kovar (4J29 alloy); the two have matched thermal expansion coefficients, ensuring the air tightness of the part, with a leakage rate of ≤1×10-3Pa·cm3 / s.

[0037] Preferably, the metal plating layers are both multilayer metal materials, with a plating layer thickness of Ni: 2.5-11.4 μm, and Au: 1.3-5.7 μm.

Claims

1. A method for packaging a multi-channel driving circuit, characterized in that: (1) A ceramic package shell is constructed by welding a ceramic base, a metal wall, a chip carrier, and external lead electrodes. (2) The ceramic substrate adopts a stepped structure design. The first step has a shell seal sintered on it. The second step has multiple internal electrode pads made according to the circuit structure, which are used as internal bonding areas. The third step has a chip carrier sintered on it. The bottom of the ceramic substrate has multiple external lead electrode pins made according to the circuit structure. The ceramic substrate material is Al2O3 multilayer ceramic. The thermal conductivity of the ceramic material is significantly higher than that of the plastic encapsulation material, which can efficiently conduct the heat generated by the chip to the external environment. Through internal structure optimization, a lighter and smaller package shape can be achieved. Secondly, the high-frequency signal loss is lower in the ceramic material, which effectively reduces the loss of the packaged product. (3) The inner electrode pads adopt a Ni-Au composite metal structure with a gold surface. The inner electrode pads are connected to the outer lead electrodes through a metal with stable strength and low impedance. The internal circuit structure is connected to the outer shell electrodes through metal vias, providing high mechanical strength and low parasitic impedance. (4) The metal wall material uses Kovar 4J29 alloy, whose coefficient of thermal expansion (CTE) is close to that of the ceramic base. This results in low internal stress when welded into a whole, preventing deformation and cracking, improving the overall mechanical strength of the ceramic shell, and achieving an airtightness leakage rate ≤1×10 -3 Pa·cm 3 / s; (5) The chip carrier is made of WCu15 alloy material with gold plating on the surface. It is used to fix the chip position during the chip sintering process, thereby improving the yield; at the same time, it increases the heat capacity of the device and improves the device power. (6) The surface of the outer lead electrode at the bottom of the housing is gold-plated, which makes the outer lead electrode easy to solder, not easy to oxidize, and has good stability; it is connected to the inner electrode pad through a metal via transmission line.

2. The packaging structure of the multi-channel driving circuit packaging method as described in claim 1, characterized in that: The invention comprises a ceramic substrate (10), a metal wall (9), a chip carrier (103), and external lead electrodes (1), (2), (3), (4), (5), (6), (7), and (8). The ceramic substrate (10) is characterized by a stepped structure and is made of Al2O3 multilayer ceramic material. The metal wall (9) on the first step is fixedly connected to the ceramic substrate (10) via a sintering process. Nine internal electrode pads (11), (21), (31), (32), (41), (51), (61), (71), and (81) are provided on the second step (102). The chip carrier (103) on the third step (101) is fixedly connected to the ceramic substrate (10) via a sintering process. External lead electrodes (1), (2), (3), (4), (5), (6), (7), and (8) are welded and fixed to the bottom of the ceramic substrate (10).

3. The packaging structure of the multi-channel driving circuit packaging method according to claim 2, characterized in that: The metal wall (9) is fixedly connected to the ceramic base (10) through a sintering process to form a cavity. The material of the metal wall (9) is Kovar 4J29 alloy.

4. The packaging structure of the multi-channel driving circuit packaging method according to claim 2, characterized in that: The ceramic base (10) is welded and fixed with external lead electrodes (1), (2), (3), (4), (5), (6), (7), and (8) on the bottom, and a metal coating is provided on the surface.

5. The packaging structure of the multi-channel driving circuit packaging method according to claim 2, characterized in that: The inner electrode pads (11), (21), (31), (32), (41), (51), (61), (71), and (81) are Ni-Au structures with a metal coating on their surface.

6. The packaging structure of the multi-channel driving circuit packaging method according to claim 5, characterized in that: The inner electrode pads (11), (21), (31), (32), (41), (51), (61), (71), and (81) are bonding areas and are connected to the outer lead electrodes (1), (2), (3), (4), (5), (6), (7), and (8) through tungsten paste metal vias.

7. The packaging structure of the multi-channel driving circuit packaging method according to claim 2, characterized in that: The chip carrier (103) is made of WCu15 alloy material and has a metal coating on its surface.

8. The packaging structure of the multi-channel driving circuit packaging method according to claim 2, characterized in that, A component sealing frame (104) is provided at one end of the bottom of the ceramic base (10).

9. The packaging structure of the multi-channel driving circuit packaging method according to claim 8, characterized in that, The surface of the component sealing frame (104) is coated with a metal coating.

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