CN205692818U - Aluminium nitride multi-layer ceramics four limit is without lead-in wire flat package shell - Google Patents

Abstract

The utility model discloses an aluminum nitride multilayer ceramic four-sided leadless flat packaging shell, which relates to the technical field of ceramic packaging. The utility model comprises a ceramic shell, the ceramic shell is opened upwards, a central pad is arranged in the center of the lower surface of the ceramic shell substrate, a lead-out pad is arranged around the central pad, and a pad is provided between the central pad and the lead-out pad. The gap, the ceramic shell is made of aluminum nitride material, there is a chip bonding area in the center of the upper surface of the ceramic shell substrate, and a wire bonding area is provided around the chip bonding area, and the wire bonding area is radial. A plurality of metal conducting grooves are arranged on the outer wall around the shell, the chip bonding area is connected with the wire bonding area through the bonding wire, and the wire bonding area is connected with the terminal pad through the metal conducting grooves. With the characteristics of strong heat dissipation capability and high reliability, it can effectively reduce the volume and weight of integrated devices, realize miniaturization, and meet the heat dissipation requirements of power devices.

Description

Aluminum Nitride Multilayer Ceramic Quad Leadless Flat Pack Housing

technical field

The utility model relates to the technical field of ceramic encapsulation, in particular to an aluminum nitride multilayer ceramic four-sided leadless flat encapsulation shell.

Background technique

CQFN (Ceramic Quad Flat No-lead) shells are mainly used to package various high-speed ADC, DAC and DDS chips. Products include ADC, DAC, DDS, GaAs MMIC switch, track and hold amplifier, mixer amplifier, power amplifier, mixer devices and converters, etc. The biggest advantage of this type of housing is that it can meet digital, digital-analog, analog and MEMS packaging, and has a wide range of cross-field applications. The commonly used lead pitch of this type of housing is 0.50mm, which has the characteristics of small parasitic parameters, small size, good heat dissipation, high application frequency, good high-frequency performance, and suitable for mass production. The current RF performance can cover the Ka band and is suitable for surface mounting. Development direction: high frequency, high speed, low cost. Ideal for aerospace and defense, automotive applications, energy, healthcare, instrumentation, motor control, process control, and process automation.

With the rapid development of electronic machines and electronic components in the direction of miniaturization, light weight, high speed, high efficiency, high integration, high reliability and high power output, the heat generated per unit volume of the device has increased sharply, which is harmful to the basic The heat dissipation of chips and packaging materials puts forward higher requirements. If the heat cannot be dissipated by the substrate in time, the device will be difficult to work normally, and even burn out in severe cases. Aluminum nitride (AlN) ceramics have high thermal conductivity (theoretical thermal conductivity is 320W/m.K, which is about 10 times that of alumina ceramics). The use of aluminum nitride ceramics can effectively improve the heat dissipation efficiency of the device, reduce the junction temperature, and improve the reliability and life of the device.

Domestic high-density and high-power packages mainly use alumina ceramic materials, metal materials, alumina ceramics + high thermal conductivity materials (tungsten copper, molybdenum copper and CPC, etc.), LTCC (Low Temperature Co-fired Ceramic) substrate materials + alumina Ceramic and LTCC substrate materials + metal materials, there is no multi-layer ceramic shell based on aluminum nitride technology. The thermal conductivity of Al ₂ O ₃ is low, and the thermal expansion coefficient does not match that of silicon; although the metal material has a high thermal conductivity, the high thermal expansion coefficient mismatch with the chip substrate is difficult to meet the packaging requirements of high-power devices. And the integration of metal shells is low; alumina ceramics + high thermal conductivity materials (tungsten copper, molybdenum copper and CPC, etc.) have high thermal conductivity, but because they want to have high mechanical properties, they must be Only by ensuring that the shell and the high thermal conductivity material have a certain welding overlap size can the reliability of the welding between the shell and the high thermal conductivity material be realized, which limits the miniaturization of its size, and the integration of the shell with high thermal conductivity material is low. Therefore, it is difficult to realize the miniaturization and integration of the shell in this mode; the combination of the LTCC substrate and alumina ceramics or metal materials can solve the problem of thermal expansion coefficient mismatch, but the thermal conductivity is only 30W/mK, and the thermal conductivity is weak ;Compared with other materials, AlN has excellent comprehensive properties and is an ideal substrate and packaging material for a new generation of high-integration and power devices.

Utility model content

The technical problem to be solved by the utility model is to provide an aluminum nitride multilayer ceramic four-sided leadless flat package shell, which has the characteristics of strong heat dissipation and high reliability, can effectively reduce the volume and weight of integrated devices, and realize miniaturization , to meet the heat dissipation requirements of power devices.

In order to solve the above-mentioned technical problems, the technical solution adopted by the utility model is: an aluminum nitride multilayer ceramic four-sided leadless flat package shell, including a ceramic shell, the ceramic shell is opened upward, and the center of the lower surface of the ceramic shell substrate is provided with The central pad is provided with lead-out pads around the central pad, and there is a gap between the central pad and the lead-out pads. The ceramic shell is made of aluminum nitride material, and there is a central pad on the upper surface of the ceramic shell substrate. In the chip bonding area, there is a wire bonding area around the chip bonding area. The wire bonding area is radial. There are a number of metal conduction grooves on the outer wall around the ceramic shell. The chip bonding area passes through the bonding wire. It is connected with the wire bonding area, and the wire bonding area is connected with the terminal pad through the metal conducting groove.

In a further technical solution, a heat sink structure is provided in the center of the ceramic shell substrate.

In a further technical solution, the material of the heat sink is one of oxygen-free copper, molybdenum copper, tungsten copper and CPC.

In a further technical solution, the section of the metal conduction groove is semicircular, and the upper end of the metal conduction groove is provided with a back cover, which is coplanar with the upper surface of the wire bonding area, and the diameter of the metal conduction groove is 0.15-0.60mm , The groove length is 0.15-4.00mm.

In a further technical solution, the lead-out pads are symmetrically distributed on opposite sides of the lower surface of the ceramic housing substrate or evenly distributed on four sides, and the number thereof is equal to the number of metal conduction grooves provided on the corresponding outer wall.

In a further technical solution, the four corners of the ceramic shell are provided with arc-shaped grooves, and the arc-shaped grooves penetrate between the upper and lower surfaces of the ceramic shell.

In a further technical solution, the pitch of the terminal pads is 0.5mm.

The beneficial effects produced by adopting the above-mentioned technical scheme are: the utility model is an aluminum nitride multilayer ceramic shell, which utilizes the excellent performance of aluminum nitride to make the design of ceramic products using aluminum nitride more flexible, and can realize electrical performance, thermal The design optimization of performance and mechanical properties can realize multi-cavity, multi-layer wiring, multi-via interconnection and airtight packaging structure, which can meet the different needs of devices, modules and components, and realize high power of devices, modules and components , high density, miniaturization, high heat dissipation and high reliability requirements.

Description of drawings

Fig. 1 is the front view of the utility model without heat sink;

Fig. 2 is the top view of Fig. 1;

Fig. 3 is the bottom view of Fig. 1;

Fig. 4 is a front view of the utility model with a heat sink;

Figure 5 is a top view of Figure 4;

Fig. 6 is the bottom view of Fig. 4;

In the figure: 1. Ceramic shell; 2. Chip bonding area; 3. Wire bonding area; 4. Sealing area; 5. Metal conduction groove; 6. Terminal pad; 7. Heat sink; plate; 9, arc groove; 10, back cover.

detailed description

Below in conjunction with accompanying drawing and specific embodiment, the utility model is described in further detail.

The structure of the present utility model is shown in Fig. 1 and Fig. 2, and comprises a ceramic shell 1, and the ceramic shell 1 opens upwards, and a central pad 8 is arranged in the center of the lower surface of the substrate of the ceramic shell 1, as shown in Fig. 3 , and the central pad 8 Lead terminal pads 6 are provided around the substrate, the ceramic shell 1 is made of aluminum nitride material, a chip bonding area 2 is provided in the center of the upper surface of the substrate, and a wire bonding area 3 is provided around the chip bonding area 2. The wire bonding area 3 is in a radial shape, surrounded by a sealing area 4, and a number of metal conduction grooves 5 are arranged on the outer wall around the ceramic shell 1, and the chip bonding area 2 is bonded to the wire by bonding wires Area 3 is connected, and the wire bonding area 3 is connected to the terminal pad 6 through the metal conduction groove 5 . The central pad 8 is used for grounding and heat dissipation.

In addition, it is also possible to have a heat sink 7 structure at the bottom center of the cavity, as shown in Figure 4, Figure 5, and Figure 6, wherein the material of the heat sink 7 is oxygen-free copper, molybdenum copper, tungsten copper and CPC. A sort of.

Wherein, the structure of the metal conduction groove 5 is that the upper end of the metal conduction groove 5 is provided with a back cover 10, the bottom surface of the back cover 10 is coplanar with the upper surface of the wire bonding area 3, and the aperture diameter of the metal conduction groove 5 is 0.15mm. ~0.60mm, the slot length is 0.15~4.00mm. Wherein the wire bonding area 3 is laterally connected to the metal conduction groove 5 .

The lead-out pads 6 are distributed symmetrically or evenly distributed in pairs on the lower surface of the ceramic housing 1, that is, the number of lead-end pads 6 on one pair of opposite sides is greater than that of the other pair of lead-end pads 6 on the opposite side. The numbers are not equal, and in addition, the total number of lead-out pads 6 is equal to the number of metal conducting grooves 5 provided on the corresponding outer wall.

The four corners of the ceramic shell 1 are provided with arc-shaped grooves 9 , and the arc-shaped grooves 9 penetrate between the upper and lower surfaces of the ceramic shell 1 .

The aluminum nitride ceramic shell of the CQFN series has the characteristics of multi-layer wiring, high reliability, and high air tightness. It has the characteristics of high wiring density, strong heat dissipation capability, and high reliability, which can effectively reduce the volume and weight of integrated devices. , to achieve miniaturization and meet the heat dissipation requirements of power devices; the ceramic shell can have 1 to 10 polygonal cavities for accommodating chips or passive devices; the ceramic shell can have a wiring structure of 2 to 30 layers; this type of shell is commonly used The terminal pitch is 0.50mm. The lead-out pads of this type of ceramic housing are evenly arranged on four sides. There are two common forms of lead-outs, one is that the lead-out pads and bonding fingers are connected through the metal conduction slots on the four sides of the shell, and the other is that the bonding fingers and lead-outs are interconnected in the form of buried layers.

The aluminum ceramic shell of CQFN series is composed of aluminum nitride ceramic body, metal sealing ring (can be determined according to customer demand) and heat sink (can be determined according to customer demand), and the cavity size is determined according to user information. Board installation requirements, determine the lead wire arrangement and the interconnection relationship of internal wiring, on this basis, carry out structural design, and conduct structural and electrical performance simulations to ensure its structural reliability and heat dissipation and electrical performance requirements. The metal sealing ring is made of iron-nickel or iron-nickel-cobalt alloy, and the heat sink is made of high thermal conductivity alloy materials such as oxygen-free copper, molybdenum-copper, tungsten-copper and CPC. Metal sealing rings are used for gold-tin sealing, parallel seam welding or laser seam welding sealing, and heat sinks are used for chip grounding or heat dissipation.

The CQFN aluminum nitride multilayer ceramic shell adopts the AlN multilayer ceramic co-firing technology. The specific process is: after the shell is tape-cast and hot-cut, the cavity is punched and the hole is metallized, and then it is printed, positioned, laminated, and heated. Cut into a single green ceramic piece, and then form a single CQFN-type aluminum nitride multilayer ceramic packaging shell for power devices or other devices through sintering, nickel plating, and gold plating.

The main packaging form of the utility model is a flat aluminum nitride multilayer ceramic shell with four sides without leads (CQFN-Ceramic Quad Flat No-lead). Aluminum nitride ceramic is a new type of high thermal conductivity substrate and packaging material, which has the characteristics of high thermal conductivity, low thermal expansion coefficient, low dielectric constant and dielectric loss, high mechanical strength, etc. Its thermal expansion coefficient is similar to that of silicon It is compatible with chip materials such as gallium arsenide, has good insulation performance and dielectric properties, has high material strength at high temperatures, is environmentally friendly, non-toxic, and has good chemical stability. It is widely used in the field of high-power electronics. Aluminum nitride multilayer ceramic technology makes the design of aluminum nitride ceramic products more flexible, can realize the design optimization of electrical performance, thermal performance and mechanical performance, and can realize multi-cavity, multi-layer wiring, multi-via interconnection and air tightness The unique packaging structure can meet the different needs of devices, modules and components, and realize the high power, high density, miniaturization and high reliability requirements of devices, modules and components.

Aluminum nitride multilayer ceramic shells are mainly used for laser diodes, high-brightness LEDs, RF and microwave packaging, radar module packaging, power module packaging, power modules, IR detectors, CCD, CMOS imaging systems, switching power supplies, and high-power integrated circuits It is widely used in the packaging of power electronics, aerospace, national defense, automobiles and locomotives, communications and other industrial fields.

Compared with the conventional LTCC integrated shell or alumina ceramic shell, the aluminum nitride multilayer ceramic shell has a higher thermal conductivity, and the highest thermal conductivity reaches 180W/m·K. It can effectively avoid the problem that the device temperature is too high and cannot work normally or even be scrapped, and can meet the heat dissipation requirements of power devices; at the same time, it has a low thermal expansion coefficient (4.7ppm), which is equivalent to silicon, and solves the thermal expansion of the ceramic shell and chip when the chip is installed The problem of mismatching coefficients can effectively release stress and improve the reliability of chip installation.

Claims (7)

1. An aluminum nitride multilayer ceramic four-sided leadless flat package shell, comprising a ceramic shell (1), the ceramic shell (1) is open upward, and a central pad (8) is arranged at the center of the lower surface of the substrate of the ceramic shell (1) ), there is a lead-out pad (6) around the central pad (8), and there is a gap between the central pad (8) and the lead-out pad (6). It is characterized in that the ceramic shell (1) adopts Made of aluminum nitride material, a chip bonding area (2) is provided in the center of the upper surface of the ceramic shell (1) substrate, and a wire bonding area (3) is provided around the chip bonding area (2). The bonding area (3) is radial, and there are a number of metal conduction grooves (5) on the outer wall around the ceramic shell (1), and the chip bonding area (2) is connected to the wire bonding area (3) by bonding wires , the wire bonding area (3) is connected to the terminal pad (6) through the metal conducting groove (5). 2 . The aluminum nitride multilayer ceramic quadrilateral leadless flat package shell according to claim 1 , wherein a heat sink ( 7 ) structure is arranged in the center of the substrate of the ceramic shell ( 1 ). 3. The aluminum nitride multilayer ceramic quadrilateral leadless flat package housing according to claim 2, wherein the material of the heat sink (7) is one of oxygen-free copper, molybdenum copper, tungsten copper and CPC. 4. The aluminum nitride multilayer ceramic quadrilateral leadless flat package shell according to claim 1 or 2, characterized in that the section of the metal conduction slot (5) is semicircular, and the upper end of the metal conduction slot (5) A back cover (10) is provided, and the back cover (10) is coplanar with the upper surface of the wire bonding area (3). The metal conduction slot (5) has an aperture diameter of 0.15-0.60 mm and a slot length of 0.15-4.00 mm. 5. The aluminum nitride multilayer ceramic quadrilateral leadless flat package housing according to claim 1 or 2, characterized in that the lead-out pads (6) are formed in pairs on the lower surface of the substrate of the ceramic housing (1). Symmetrical distribution or uniform distribution on four sides, the number of which is equal to the number of metal conduction grooves (5) provided on the corresponding outer wall. 6. The aluminum nitride multilayer ceramic quadrilateral leadless flat package shell according to claim 1 or 2, characterized in that the four corners of the ceramic shell (1) are provided with arc-shaped grooves (9), and the arc-shaped grooves ( 9) It penetrates between the upper and lower surfaces of the ceramic shell (1). 7. The aluminum nitride multilayer ceramic quadrilateral leadless flat package housing according to claim 1 or 2, characterized in that the pitch of the terminal pads (6) is 0.5mm.