Structure of connecting printed wiring boards, method of connecting printed wiring boards, and adhesive having anisotropic conductivity

A structure of connecting printed wiring boards, the structure electrically connecting a plurality of first electrodes provided to be adjacent to each other on a first board with a plurality of second electrodes provided to be adjacent to each other on a second board through an adhesive that contains conductive particles and that has anisotropic conductivity;

• wherein:
• (a) the adhesive is placed between the first electrodes and the second electrodes, which face each other;
• (b) the adhesive is heated and pressed to form an adhesive layer between the first board and the second board;
• and
• (c) in the adhesive layer, a cavity portion is formed between the multiple first electrodes and between the multiple second electrodes,
• wherein the adhesive not only covers the first electrodes and the second electrodes but also covers the entire surface of the first board and the second board at positions between the first electrodes and between the second electrodes,
• wherein in a cross section obtained by cutting, in a direction perpendicular to the thickness direction, a region between the first electrodes and the second electrodes, which face each other in the thickness direction of the first board and the second board, when A1 represents a total area of the adhesive layer and the cavity portion both existing between the electrodes provided to be adjacent to each other along a surface direction, which is perpendicular to the thickness direction, and A2 represents an area of the cavity portion, the ratio of the area of the cavity portion to the total area, which is A2/A1, is 0.3 or more and 0.9 or less, and
• wherein the conductive particles constitute 0.0001 vol. % or more and 0.2 vol. % or less of the total volume of the adhesive.