A high temperature semiconductor refrigeration device and packaging method

Abstract

The present invention provides a high-temperature semiconductor refrigeration device and packaging method, including crystal grains, copper-clad ceramic substrates, crystal grain metallized nickel layers, electrodes, and nickel foam layers on the nickel metal layers on the upper and lower surfaces of the crystal grains, and nano-silver solder connection layers, and device packaging is achieved through preheating, hot pressing and other processes. Aiming at the problems of low silver-nickel diffusion efficiency and low connection strength, the present invention constructs a nickel foam alloy layer, uses a nano-metal porous network, and quickly forms a silver-nickel composite structure with nano-silver under hot pressing, and combines online process digital monitoring to enhance the silver-nickel interface connection strength, thereby improving the thermoelectric transport performance and service reliability of semiconductor refrigeration devices.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor device manufacturing, and in particular relates to a high-temperature semiconductor refrigeration device and a packaging method. Background Art

[0002] Semiconductor refrigerators are a refrigeration technology based on semiconductor materials that can achieve rapid cooling and heating. They are very suitable for application scenarios that require rapid temperature control. They have the characteristics of small size, high reliability, zero pollution emissions, and a wide operating temperature range. They are key components to ensure the stable operation of high heat flux density electronic devices, optoelectronic devices, laser sensor devices, and medical detection devices.

[0003] Commonly used thermoelectric crystal grain-substrate interconnection materials are lead-free solder, gold-tin solder, etc., and the melting temperature of the solder usually needs to be 100-300K higher than the device operating temperature. Due to the low melting temperature of the solder, the device operating temperature is lower, and it is difficult to function under high temperature conditions. At the same time, due to the low electrical conductivity, thermal conductivity and melting point of the solder, it is difficult to meet the high temperature and high power density packaging application requirements of semiconductor refrigeration devices. The electrical conductivity, thermal conductivity and reliability of sintered silver solder paste have been greatly improved, and the melting point of sintered silver exceeds 900℃, which is suitable for semiconductor refrigeration sheets that need to be resistant to high temperature service. The nickel metal layer is the most common metallization layer of thermoelectric crystal grains, but nickel will oxidize during the sintering process. Nickel oxide will hinder the formation of metal bond connection between silver and nickel, thereby reducing the connection strength. In addition, nickel and silver are almost completely insoluble in the solid state and cannot form a solid solution or alloy. It is difficult to form a silver-nickel interconnection joint with high connection strength during low-temperature sintering. The mutual diffusion rate of silver-nickel is slow, so the silver-nickel interface connection strength is low. At the same time, traditional solder packaging will cause welding voids during the welding process, resulting in reduced device reliability and transportation performance. Summary of the invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a high-temperature semiconductor refrigeration device and a packaging method. The present invention constructs a foam nickel metal layer on the thermoelectric grain metallization layer, utilizes the structural characteristics of nanosilver particles and the porous network-like nickel metal layer, and combines the nanoscale effect to achieve rapid mutual diffusion of silver and nickel, enhance the silver-nickel interface connection strength, and improve the thermoelectric transport performance and service reliability of the semiconductor refrigeration device.

[0005] A high-temperature semiconductor refrigeration device comprises an upper and a lower substrate, the two substrates have the same structure, and a P-type electric arm and / or an N-type electric arm is located between the two substrates.

[0006] Furthermore, the substrate includes a ceramic plate, a copper electrode is arranged on the surface of the ceramic plate, a first nickel metal layer is deposited on the surface of the copper electrode, a first nickel foam metal layer is attached to the surface of the first nickel metal layer, and nano silver solder is printed on the surface of the first nickel foam metal layer; the P-type electric arm and / or the N-type electric arm includes an electric arm matrix, a second nickel metal layer is deposited on the upper and lower surfaces of the electric arm matrix, and a second nickel foam metal layer is attached to the surface of the second nickel metal layer.

[0007] A packaging method for a high-temperature semiconductor refrigeration device comprises the following steps:

[0008] S1: preparing substrate;

[0009] S2: preparing the electric arm matrix;

[0010] S3: preparing a P-type electric arm and an N-type electric arm;

[0011] S4: Fix the two substrates and the electric arm;

[0012] S5: Sintering and connecting the structure by hot pressing.

[0013] Furthermore, S1 is specifically:

[0014] S1.1 Copper electrodes are attached to the surfaces of the two ceramic plates by sintering or etching to form a copper-clad ceramic substrate;

[0015] S1.2: depositing a 3-5 μm nickel metal layer on the surface of the copper electrode by chemical plating to obtain a first nickel metal layer, and then depositing a 3-5 μm zinc-nickel alloy on the surface of the first nickel metal layer by electroplating;

[0016] S1.3: Dissolve 20-200 g of glacial acetic acid with a purity of ≥99.8% and 60-300 g of fatty alcohol polyoxyethylene ether with a purity of ≥99.8% in 1000-3000 ml of water to prepare a selective corrosion solution;

[0017] S1.4: immerse the copper-clad ceramic substrate in S1.2 in a corrosion solution for 20-60 minutes to remove zinc by selective corrosion;

[0018] S1.5: Finally, acetone, ethanol and deionized water are used for washing in sequence, and nitrogen is blown to dry, so as to prepare a first nickel foam metal layer with a network structure on the surface of the first nickel metal layer;

[0019] S1.6: coating the nano silver solder on the surface of the first nickel foam metal layer by screen printing technology to obtain a first substrate;

[0020] S1.7: Repeat steps S1.1-S1.6 to prepare a second substrate.

[0021] Furthermore, the nano silver solder is a bimodal nano silver paste with nano silver particle sizes of 50 nm and 10 nm, with a weight ratio of 50:1.

[0022] Furthermore, S2 is specifically:

[0023] After the P-type and N-type thermoelectric material crystal rods are cut into wafers, a 3-5μm nickel metal layer is deposited on the upper and lower surfaces of the slices by chemical plating to obtain a second nickel metal layer, and then a 3-5μm zinc-nickel alloy is deposited on the surface of the second nickel metal layer by electroplating to obtain an electric arm substrate.

[0024] Furthermore, S3 is specifically:

[0025] S3.1: Use 20-200g of glacial acetic acid with a purity of ≥99.8% and 60-300g of fatty alcohol polyoxyethylene ether with a purity of ≥99.8% and dissolve them in 1000-3000ml of water to prepare a selective corrosion solution;

[0026] S3.2: Immerse the electric arm substrate prepared in S2 in a corrosion solution for 20-60 minutes to remove zinc by selective corrosion;

[0027] S3.3: Finally, acetone, ethanol and deionized water are used for washing in turn, and nitrogen is blown to dry, thereby preparing a second nickel foam metal layer having a network structure on the surface of the second nickel metal layer, and obtaining a substrate having a nickel foam metal layer with a network structure on both the upper and lower surfaces;

[0028] S3.4: Paste the substrate having a network structure nickel foam metal layer on both the upper and lower surfaces obtained in S3.3 onto the wafer ring, and use a dicing device to cut the substrate into grains with a specified aspect ratio, thereby obtaining a P-type electric arm and an N-type electric arm.

[0029] Furthermore, S4 is specifically:

[0030] Place one of the substrates horizontally, and then use the die bonding equipment to place the P-type and N-type electric arms formed by S3 on the substrate electrodes coated with nanosilver solder; then use the mold clamping device to align the electrodes of the other substrate coated with nanosilver solder and fix them to the other side of the P-type and N-type electric arms. Finally, the two substrates and electric arms are fixed into a symmetrical sandwich structure.

[0031] Furthermore, S5 is specifically:

[0032] The structure obtained by S4 is preheated at 150-200°C at a certain heating rate. At the same time, the resistance change of the cooling plate is monitored. If the resistance change is less than 5% / min during the preheating stage, the preheating is stopped, and then the temperature is raised to 240-300°C for insulation heating. During the insulation heating stage, a pressure of 0.5-1.5MPa is applied to the surface of the cooling plate. If the resistance change is less than 0.5% / min during the insulation heating stage, the insulation heating is stopped.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. A foam nickel alloy layer was constructed, and the nanoporous network was used to quickly form a silver-nickel composite structure with nanosilver under hot pressing. Combined with online process digital monitoring, the large-scale packaging process of high-temperature semiconductor refrigeration chips was realized.

[0035] 2. Realize a high-temperature resistant, high-reliability semiconductor cooling sheet based on nanosilver solder paste, and form a packaging process that can be manufactured on a large scale. Construct a foamed nickel layer, which can embed nanosilver into the foam voids to enhance the connection strength. At the same time, the foamed structure is conducive to the removal of organic matter during the welding process and prevent the formation of voids. It can effectively improve the welding strength, prevent the formation of voids, and greatly improve the service temperature and service reliability of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the packaging structure of the high-temperature semiconductor refrigeration device provided by the present invention. DETAILED DESCRIPTION

[0037] The invention discloses a high-temperature semiconductor refrigeration device, comprising two upper and lower substrates, the two substrates having the same structure, and a P-type electric arm and / or an N-type electric arm being located between the two substrates.

[0038] The substrate includes a ceramic plate 1, a copper electrode 2 is arranged on the surface of the ceramic plate 1, a first nickel metal layer 3 is deposited on the surface of the copper electrode 2, a first nickel foam metal layer 4 is attached to the surface of the first nickel metal layer 3, and nano silver solder 5 is printed on the surface of the first nickel foam metal layer 4; the P-type electric arm and / or the N-type electric arm includes an electric arm matrix 8, a second nickel metal layer 7 is deposited on the upper and lower surfaces of the electric arm matrix 8, and a second nickel foam metal layer 6 is attached to the surface of the second nickel metal layer 7.

[0039] A packaging method for a high-temperature semiconductor refrigeration device comprises the following steps:

[0040] S1: Preparation of substrate

[0041] S1.1 Copper electrodes 2 are attached to the surfaces of two ceramic plates 1 by sintering or etching to form a copper-clad ceramic substrate;

[0042] S1.2: depositing a 3-5 μm nickel metal layer on the surface of the copper electrode 2 by chemical plating to obtain a first nickel metal layer 3, and then depositing a 3-5 μm zinc-nickel alloy on the surface of the first nickel metal layer 3 by electroplating;

[0043] S1.3: Dissolve 20-200 g of glacial acetic acid with a purity of ≥99.8% and 60-300 g of fatty alcohol polyoxyethylene ether with a purity of ≥99.8% in 1000-3000 ml of water to prepare a selective corrosion solution;

[0044] S1.4: immerse the copper-clad ceramic substrate in S1.2 in a corrosion solution for 20-60 minutes to remove zinc by selective corrosion;

[0045] S1.5: Finally, acetone, ethanol and deionized water are used for washing in sequence, and nitrogen is blown to dry, so as to prepare a first nickel foam metal layer 4 having a network structure on the surface of the first nickel metal layer 3;

[0046] S1.6: On the surface of the first nickel foam metal layer 4, the nano silver solder 5 is coated on the surface of the first nickel foam metal layer 4 by screen printing technology to obtain a first substrate;

[0047] The nano silver solder is a bimodal nano silver paste with nano silver particle sizes of 50 nm and 10 nm, with a weight ratio of 50:1.

[0048] S1.7: Repeat steps S1.1-S1.6 to prepare a second substrate.

[0049] S2: Preparation of electric arm matrix

[0050] After the P-type and N-type thermoelectric material crystal rods are cut into wafers, a 3-5μm nickel metal layer is deposited on the upper and lower surfaces of the slices by chemical plating to obtain a second nickel metal layer 7, and then a 3-5μm zinc-nickel alloy is deposited on the surface of the second nickel metal layer 7 by electroplating to obtain an electric arm substrate.

[0051] S3: Prepare P-type electric arm and N-type electric arm

[0052] S3.1: Use 20-200g of glacial acetic acid with a purity of ≥99.8% and 60-300g of fatty alcohol polyoxyethylene ether with a purity of ≥99.8% and dissolve them in 1000-3000ml of water to prepare a selective corrosion solution;

[0053] S3.2: Immerse the electric arm substrate prepared in S2 in a corrosion solution for 20-60 minutes to remove zinc by selective corrosion;

[0054] S3.3: Finally, acetone, ethanol and deionized water are used for washing, and nitrogen is blown to dry, so as to prepare a second nickel foam metal layer 6 having a network structure on the surface of the second nickel metal layer 7, and obtain a substrate having a nickel foam metal layer with a network structure on both the upper and lower surfaces;

[0055] S3.4: Paste the substrate having a network structure nickel foam metal layer on both the upper and lower surfaces obtained in S3.3 onto the wafer ring, and use a dicing device to cut the substrate into grains with a specified aspect ratio, thereby obtaining a P-type electric arm and an N-type electric arm.

[0056] S4: Fix the two substrates and the electric arm

[0057] Place one of the substrates horizontally, and then use the die bonding equipment to place the P-type electric arm and the N-type electric arm formed by S3 on the substrate electrode coated with the nanosilver solder 5; then use the mold clamping device to align the electrodes of the other substrate coated with the nanosilver solder 5 and fix them to the other side of the P-type electric arm and the N-type electric arm; finally, fix the two substrates and the electric arm into a symmetrical sandwich structure, as shown in the attached figure. Figure 1 shown.

[0058] S5: Sintering and connecting the structure by hot pressing

[0059] The structure obtained by S4 is preheated at 150-200°C at a certain heating rate. At the same time, the resistance change of the cooling plate is monitored. If the resistance change is less than 5% / min during the preheating stage, the preheating is stopped, and then the temperature is raised to 240-300°C for insulation heating. During the insulation heating stage, a pressure of 0.5-1.5MPa is applied to the surface of the cooling plate. If the resistance change is less than 0.5% / min during the insulation heating stage, the insulation heating is stopped.

Claims

1. A high-temperature semiconductor refrigeration device, characterized in that: It comprises two upper and lower substrates, the two substrates have the same structure, and the P-type electric arm and / or the N-type electric arm are located between the two substrates; The substrate comprises a ceramic plate (1), a copper electrode (2) is arranged on the surface of the ceramic plate (1), a first nickel metal layer (3) is deposited on the surface of the copper electrode (2), a first foamed nickel metal layer (4) is attached to the surface of the first nickel metal layer (3), and nano silver solder (5) is printed on the surface of the first foamed nickel metal layer (4); the P-type electric arm and / or the N-type electric arm comprises an electric arm substrate (8), a second nickel metal layer (7) is deposited on the upper and lower surfaces of the electric arm substrate (8), and a second foamed nickel metal layer (6) is attached to the surface of the second nickel metal layer (7).

2. A packaging method for a high-temperature semiconductor refrigeration device as claimed in claim 1, characterized in that: The following steps are involved: S1: preparing substrate; S1.1 Copper electrodes (2) are attached to the surfaces of the two ceramic plates (1) by sintering or etching to form a copper-clad ceramic substrate; S1.2: depositing a nickel metal layer of 3 to 5 μm on the surface of the copper electrode (2) by chemical plating to obtain a first nickel metal layer (3), and then depositing a zinc-nickel alloy of 3 to 5 μm on the surface of the first nickel metal layer (3) by electroplating; S1.3: Dissolve 20-200 g of glacial acetic acid with a purity of ≥99.8% and 60-300 g of fatty alcohol polyoxyethylene ether with a purity of ≥99.8% in 1000-3000 ml of water to prepare a selective corrosion solution; S1.4: immerse the copper-clad ceramic substrate in S1.2 in a corrosion solution for 20-60 minutes to remove zinc by selective corrosion; S1.5: finally, washing with acetone, ethanol and deionized water in sequence, and drying with nitrogen, to prepare a first nickel foam metal layer (4) having a network structure on the surface of the first nickel metal layer (3); S1.6: coating the nano silver solder (5) on the surface of the first nickel foam metal layer (4) by screen printing technology to obtain a first substrate; S1.7: Repeat steps S1.1-S1.6 to prepare a second substrate; S2: preparing the electric arm matrix; S3: preparing a P-type electric arm and an N-type electric arm; S4: Fix the two substrates and the electric arm; S5: Sintering and connecting the structure by hot pressing.

Images