Preparation method of low-temperature sintering nanosilver paste heat conductivity testing sample

Abstract

The invention discloses a preparation method of a low-temperature sintering nanosilver paste heat conductivity testing sample. The preparation method comprises the following steps of preparing nanosilver paste; adhering a circular die onto a heat release adhesive tape, and filling the nanosilver paste into the whole die; drying an organic solvent in the nanosilver paste; pressing the nanosilver paste on a worktable, and continuing to fill the nanosilver paste until the nanosilver paste is fully filled into the whole die; pressing again until the nanosilver paste is fully filled into the die; removing the heat release adhesive tape, adhering the other surface of the die to a new heat release adhesive tape, and pressing until the nanosilver paste is fully filled into the die; removing the heat release adhesive tape, and sintering the semi-dry nanosilver paste at low temperature; grinding the sample, until the testing sample meeting the testing size requirement is formed. The preparation method has the advantages that the sample meeting the testing requirement is met; after the nanosilver paste is sintered, the structure is denser, and the mechanical strength and heat conduction property of the sample are improved; by using the heat release adhesive tape, the adhering with the nanosilver paste is avoided, and the sample integrity is better.

Description

Technical field [0001] The invention relates to a method for testing the thermal conductivity of thermal interface materials, in particular to a method for preparing a sample for testing the thermal conductivity of nano silver, which is applied to the technical field of lead-free thermal interface thermal conductivity testing materials. Background technique [0002] Traditional thermal interface materials such as thermally conductive adhesives and alloy solders have low thermal conductivity, which can no longer meet the rapidly developing thermal management needs of microelectronic packaging. As a new type of lead-free thermal interface material, low-temperature sintered nano silver paste has high thermal conductivity that other traditional thermal interface materials do not have. At present, due to the limitation of the heat resistance of other materials in the packaging system, the sintering temperature must be controlled in a lower temperature range. The selection of the organ...

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Problems solved by technology

[0003] 1. Make a square high-temperature-resistant ceramic substrate, coat the center of the substrate with a nickel layer and a silver layer, apply the viscous nano-silver paste evenly on the coating, and then bond the thermal test chip and the silver paste to the substrate After sintering and connecting to the circuit, the thermal conductivity of the nano-silver paste can be tested by testing the thermal resistance of the thermal test chip, but the ceramic substrate and thermal test chip used in this method are expensive to manufacture, and the operation process is relatively cumbersome.

[0004] 2. First make two identical round copper sheets, the diameter of which meets the requirements of the detection size, plate a nickel layer and a silver layer on one surface of each copper sheet, and stick the two copper sheets with viscous nano-silver paste. Connected together, the contact surface is the coated side, which presents a structure similar to a "sandwich". After sintering, use a laser thermal conductivity meter to measure the thermal conductivity of the structure, and finally calculate the nano-silver paste after sintering. The thermal conductivity of the method is low, but the thermal conductivity obtained by calculation has a large error, which cannot truly reflect the thermal conductivity of nano-silver paste

[0005] 3. Dry the prepared nano-silver paste and sinter it in a mold. After being polished, a sample that meets the test requirements is obtained. Use a laser thermal conductivity meter to measure the thermal conductivity of the sample. This method has the lowest cost and the measured The thermal conductivity can most truly reflect the thermal conductivity of the nano-silver paste after sintering. The operation process is simple and easy to realize. However, the uniformity of the traditional method of using silver paste to make thermal conductive materials is not ideal. Whether internal defects in the material will occur during the curing process will affect the Produce local uneven heat conduction of materials

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