Preparation method of anisotropic conductive adhesive of liquid metal

Abstract

The invention discloses a preparation method of an anisotropic conductive adhesive of liquid metal. The preparation method comprises the following steps: material preparation: weighing a liquid metal alloy and an adhesive according to a weight ratio; the liquid metal is dispersed in the adhesive to be stirred, then defoaming is conducted in an ultrasonic mode, and the mixture of the liquid metal and the adhesive is obtained; the mixtures are smeared on a circuit board, then another base body is buckled on the circuit board, curing forming is carried out, and the liquid metal anisotropic conductive adhesive is obtained and has good conductivity and good adhesion in the specific direction, various base materials can be firmly bonded, and the reliability and stability of electronic elements are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of conductive adhesives, and in particular relates to a method for preparing anisotropic conductive adhesive of liquid metal. Background Art

[0002] Anisotropic conductive adhesive is a type of conductive adhesive, also known as anisotropic conductive adhesive, anisotropic conductive adhesive, referred to as ACA / ACP in English. Anisotropic conductive adhesive has the functions of unidirectional conductivity and gluing and fixing, which can realize the conduction of current in the vertical direction and insulation in the horizontal direction. This is its greatest feature. It is a conductive adhesive used in the field of electronic component packaging.

[0003] Conductive adhesive is made of polymer materials and conductive particles. Its conductivity is close to that of metal. According to the direction of conduction, it can be divided into two categories: isotropic conductive adhesive (ICA) and anisotropic conductive adhesive (ACA). In comparison, anisotropic conductive adhesive has higher technical content. Compared with anisotropic conductive film (ACF), which is also anisotropic conductive adhesive, anisotropic conductive adhesive is paste-like in appearance and has the advantages of stronger adhesion and higher reliability. It can be used in the field of fine printed circuit board manufacturing. Summary of the invention

[0004] The purpose of the present invention is to design a method for preparing anisotropic conductive adhesive of liquid metal.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A method for preparing anisotropic conductive adhesive of liquid metal, the preparation method is as follows: Step 1: Material preparation: weigh the liquid metal alloy and adhesive according to the weight ratio; Step 2: preparing a mixture: dispersing the liquid metal in the adhesive and stirring, and then degassing by ultrasonic means to obtain a mixture of the liquid metal and the adhesive; Step 3: Prepare conductive adhesive: Apply the above mixture on the circuit board respectively, then buckle another substrate on the circuit board, and solidify to obtain anisotropic conductive adhesive of liquid metal.

[0006] Furthermore, the liquid metal is an alloy of single element gallium, the melting point of which is lower than 105 degrees Celsius, and the liquid metal is a binary or ternary alloy of gallium.

[0007] Furthermore, the adhesive adopts a single component, and the polymer material in the single component adhesive is a polymer or a prepolymer.

[0008] Furthermore, after the anisotropic conductive adhesive of the liquid metal is solidified, pressure, bending force or tension is applied to the conductive adhesive.

[0009] The following beneficial effects can be obtained through the above technical solution: The liquid metal conductive adhesive of the present invention is widely used in the fields of touch screens, smart cards, radio frequency identification (RFID) technology, flip chip integration, and flexible circuit boards (FPC), and is particularly suitable for the strict requirements for ultra-fine pitch circuit assembly and packaging in the microelectronics industry. It has good conductivity in a specific direction and good adhesion, and can firmly bond various substrates to improve the reliability and stability of electronic components. DETAILED DESCRIPTION

[0010] The present invention will be further described below in conjunction with embodiments: Embodiment: A method for preparing anisotropic conductive adhesive of liquid metal, Step 1: Weighing liquid metal alloy and adhesive according to weight ratio to prepare liquid metal anisotropic conductive adhesive: the adhesive used in the present invention can be divided into a single-component adhesive, dispersing liquid metal in the adhesive to obtain a mixture of liquid metal and adhesive, removing bubbles, and storing for standby use; Step 2: Specific application of liquid metal anisotropic conductive adhesive: Apply the mixture of liquid metal and adhesive with bubbles removed to the traditional circuit board, and then place another substrate on the mixture to form a three-layer sandwich structure. The liquid metal conductive adhesive is obtained by curing.

[0011] In a blast drying oven, cure at 80℃ for 2h, 120℃ for 2h, 150℃ for 2h, and 180℃ for 2h, and cool to room temperature for use. Set the temperature according to the glass transition temperature of the sample, apply pressure perpendicular to the sample direction under this temperature environment, and cool to room temperature while maintaining the pressure to obtain liquid metal anisotropic conductive adhesive. At this time, the conductive adhesive has good conductivity along the force direction, with a resistance value of less than 100mΩ, and is in an insulating state perpendicular to the pressure direction.

[0012] The liquid metal conductive adhesive of the present invention is widely used in the fields of touch screens, smart cards, radio frequency identification (RFID) technology, flip chip integration, and flexible circuit boards (FPC), and is particularly suitable for the strict requirements for ultra-fine pitch circuit assembly and packaging in the microelectronics industry. It has good conductivity in a specific direction and good adhesion, and can firmly bond various substrates to improve the reliability and stability of electronic components.

[0013] The above are all preferred embodiments of the present invention. For ordinary technicians in this technical field, without departing from the principle of the present invention, various equivalent modifications to the present invention belong to the protection scope of the claims attached to this application.

Claims

1. A method for preparing anisotropic conductive adhesive of liquid metal, characterized in that: The preparation method is as follows: Step 1: Material preparation: weigh the liquid metal alloy and adhesive according to the weight ratio; Step 2: preparing a mixture: dispersing the liquid metal in the adhesive and stirring, and then degassing by ultrasonic means to obtain a mixture of the liquid metal and the adhesive; Step 3: Prepare conductive adhesive: Apply the above mixture on the circuit board respectively, then buckle another substrate on the circuit board, and solidify to obtain anisotropic conductive adhesive of liquid metal.

2. The method for preparing anisotropic conductive adhesive of liquid metal according to claim 1, characterized in that: The liquid metal is an alloy of elemental gallium, which has a melting point below 105 degrees Celsius.

3. The method for preparing anisotropic conductive adhesive of liquid metal according to claim 2, characterized in that: The liquid metal is a binary or ternary alloy of gallium.

4. The method for preparing anisotropic conductive adhesive of liquid metal according to claim 1, characterized in that: The adhesive adopts a single component, and the high molecular material in the single component adhesive is a high molecular polymer or a prepolymer.

5. The method for preparing anisotropic conductive adhesive of liquid metal according to claim 1, characterized in that: After the anisotropic conductive adhesive of the liquid metal is cured, pressure, bending force or tension is applied to the conductive adhesive.