US-12617976-B2 - Method for manufacturing joined body, joined body, and hot-melt adhesive sheet

Abstract

A method for manufacturing a joined body includes subjecting a first electronic component and a second electronic component to thermocompression bonding with a hot-melt adhesive sheet interposed therebetween. The hot-melt adhesive sheet includes a binder and electroconductive particles. The binder includes a crystalline polyamide resin and a crystalline polyester resin. When a melt viscosity of the hot-melt adhesive sheet is measured under a condition of a heating rate of 5° C./min. the hot-melt adhesive sheet has a ratio of a melt viscosity at 20° C. lower than a thermocompression bonding temperature to a melt viscosity at the thermocompression bonding temperature of 10 or higher.

Inventors

• Hiroyuki Kumakura
• Tomoyuki Abe

Assignees

• DEXERIALS CORPORATION

Dates

Publication Date

20260505

Application Date

20210603

Priority Date

20200605

Claims (13)

1. 1 . A method for manufacturing a joined body, the method comprising subjecting a first electronic component comprising a first conductive portion and a second electronic component comprising a second conductive portion to thermocompression bonding with a hot-melt adhesive sheet interposed therebetween, to connect the first conductive portion and the second conductive portion, the hot-melt adhesive sheet comprising a binder and electroconductive particles, the binder comprising a crystalline polyamide resin and a crystalline polyester resin, wherein when a melt viscosity of the hot-melt adhesive sheet is measured under a condition of a heating rate of 5° C./min, the hot-melt adhesive sheet has a ratio of a melt viscosity at 20° C. lower than a thermocompression bonding temperature to a melt viscosity at the thermocompression bonding temperature of 10 or higher.
2. 2 . The method according to claim 1 , wherein when the melt viscosity of the hot-melt adhesive sheet is measured under the condition of 5° C./min, the hot-melt adhesive sheet has a ratio of a melt viscosity at 100° C. to a melt viscosity at 120° C. of 10 or higher.
3. 3 . The method according to claim 1 , wherein a mass ratio of the crystalline polyamide resin and the crystalline polyester resin is from 10:90 to 90:10.
4. 4 . The method according to claim 1 , wherein the electroconductive particles comprise: a base particle made of a first electroconductive material; and a coating layer provided on a surface of the base material and made of a second electroconductive material which is different from the first electroconductive material.
5. 5 . The method according to claim 1 , wherein an average particle diameter of the electroconductive particles is 70% or more than a thickness of the hot-melt adhesive sheet.
6. 6 . The method according to claim 1 , wherein each of the first electronic component and the second electronic component comprises a base material, and the base material of at least one of the first electronic component and the second electronic component is composed of polyvinyl chloride.
7. 7 . The method according to claim 1 , wherein the thermocompression bonding temperature is from 110° C. to 130° C.
8. 8 . A joined body comprising: a first electronic component comprising a first conductive portion; a second electronic component comprising a second conductive portion; and an adhesive layer connecting the first conductive portion and the second conductive portion, wherein the adhesive layer comprises; a binder comprising a crystalline polyamide resin and a crystalline polyester resin; and electroconductive particles, and when a melt viscosity is measured under a condition of a heating rate of 5° C./min, the adhesive layer has a ratio of a melt viscosity at 100° C. to a melt viscosity at 120° C. of 10 or higher.
9. 9 . The joined body according to claim 8 , wherein each of the first electronic component and the second electronic component comprises a base material, and the base material of at least one of the first electronic component and the second electronic component is composed of polyvinyl chloride.
10. 10 . A hot-melt adhesive sheet comprising: electroconductive particles; and a binder comprising a crystalline polyamide resin and a crystalline polyester resin, wherein when a melt viscosity is measured under a condition of a heating rate of 5° C./min, the hot-melt adhesive sheet has a ratio of a melt viscosity at 100° C. to a melt viscosity at 120° C. of 10 or higher.
11. 11 . The hot-melt adhesive sheet according to claim 10 , wherein a mass ratio of the crystalline polyamide resin and the crystalline polyester resin is 10:90 to 90:10.
12. 12 . The hot-melt adhesive sheet according to claim 10 , wherein the electroconductive particles comprise: a base particle made of a first electroconductive material; and a coating layer provided on a surface of the base material and made of a second electroconductive material which is different from the first electroconductive material.
13. 13 . The hot-melt adhesive sheet according to claim 10 , wherein an average particle diameter of the electroconductive particles is 70% or more than a thickness of the hot-melt adhesive sheet.

Description

TECHNICAL FIELD The present technology relates to a method of manufacturing a joined body that uses a hot-melt adhesive sheet containing electroconductive particles and to a joined body. This application claims priority based on Japanese Patent Application No. 2020-098843 filed in Japan on Jun. 5, 2020, and the contents of this application is hereby incorporated by reference. BACKGROUND TECHNOLOGY Conventionally, connecting materials such as anisotropic conductive film (ACF), anisotropic conductive paste (ACP), or the like have been used as means for connecting electronic components together. ACF is a connecting material that is, for example, conductive particles dispersed in an insulating binder containing thermoset resin in a film shape. ACP is a connecting material that is, for example, conductive particles dispersed in an insulating binder containing thermoset resin in the form of a paste. Binder containing thermoset resin can be thermoset to connect the electrode parts of electronic components to be connected by anisotropic conduction by performing thermo-compression with ACF or ACP therebetween. ACF and ACP are examples of an adhesive film or an adhesive agent containing electroconductive particles. In recent years, connecting in a short time at low temperature and low pressure has been in demand for connections between electronic components. Connecting at low temperature is in demand from the perspective of reducing thermal damage to electronic components, the perspective of preventing heating temperature variability when connecting, the perspective of reducing the load on mounting equipment, and the like. Connecting at low pressure is in demand from the perspective of damage due to substrate characteristics (substrate thickness, structure, and material) and the like. Connecting in a short time period is in demand from the perspective of productivity and the like. However, because thermoset resin is used for conventional ACF, attempts to achieve low temperature and short time cause hardening to occur while being stored, so storage duration must be shortened, and therefore this is not suitable for practical use. In addition, from the perspective of productivity, there is demand for storage stability for roughly 1 to 2 years but supporting this with ACF that uses thermoset resin has been difficult. Here, thermoplastic ACF containing crystalline resin and amorphous resin as an ACF that maintains sufficient connection resistance and enables connecting at low temperature, low pressure, and in a short time has been proposed (for example, see Patent Document 1). This type of ACF and ACP is used for an anisotropic conductive connection between a first electronic component and a second electronic component each having a plurality of opposing terminals and is also used as an anisotropic conductive connection in the case that at least one of the first electronic component or the second electronic component is provided with a full surface electrode. Note, this is of course used for electrical connections for terminals that are full surface electrodes. However, even with these ACFs, there were cases where sufficient connection reliability was not obtained for the case that the adherend is a difficult-to-adhere material such as PVC (polyvinylchloride). CITATION LIST Patent Documents Patent Document 1: Japanese Patent Number 5964187Patent Document 2: Japanese Unexamined Patent Application Publication No. 2017-117468 SUMMARY OF INVENTION Problem to be Solved by Invention In light of this manner of conventional circumstances, the present technology proposes to provide a method of manufacturing a joined body that can achieve superior adhesive strength and connection reliability, a joined body, and a hot-melt adhesive sheet containing electroconductive particles. Means to Solve the Problem A method for manufacturing a joined body according to the present technology is a method for manufacturing a joined body for connecting a conductive portion of a first electronic component and a conductive portion of a second electronic component, including: subjecting the first electronic component and the second electronic component to thermocompression bonding with a hot-melt adhesive sheet containing electroconductive particles containing electroconductive particles in a binder containing crystalline polyamide resin and crystalline polyester resin interposed therebetween; wherein when the melt viscosity of the hot-melt adhesive sheet containing electroconductive particles is measured using a condition of heating rate of 5° C./min, the ratio of the melt viscosity at 20° C. lower than the thermocompression bonding temperature to the melt viscosity at the thermocompression bonding temperature is 10 or higher. The joined body according to the present technology includes: a first electronic component; a second electronic component; and an adhesive layer connecting a conductive portion of the first electronic component and a conductive