METHOD FOR EVALUATING COMPATIBILITY OF THERMOSETTING RESIN COMPOSITION, THERMOSETTING RESIN COMPOSITION, PREPREG, RESIN FILM, LAMINATED PLATE, MULTILAYER PRINTED WIRING BOARD, AND SEMICONDUCTOR PACKAGE

1 . A method for evaluating a compatibility of a thermosetting resin composition containing at least two kinds of resins and an inorganic filler, the method comprising the following steps 1A and 2A:

Step 1A: a step of obtaining a reflected electronic image of a cross section of a cured product of the thermosetting resin composition using a scanning electron microscope at an observation magnification of 50 to 250 times; and

Step 2A: a step in which, in the reflected electronic image, a phase-separated resin region is referred to as a separation part and a remaining region is referred to as a non-separation part, and the image is binarized such that the separation part has one value and the non-separation part has the other value, and an area ratio of a region of the non-separation part of the resultant binarized image to a total region of the binarized image (the area of the region of the non-separation part×100/area of the total region of the binarized image) is calculated as the area ratio R w of the non-separation part.

2 . A method for evaluating a compatibility of a thermosetting resin composition containing at least two kinds of resins and an inorganic filler, the method comprising the following steps 1B and 2B:

Step 1B: a step of obtaining a reflected electronic image of a cross section of a cured product of the thermosetting resin composition using a scanning electron microscope; and

Step 2B: a step in which, in the reflected electronic image, a phase-separated resin region is referred to as a separation part and an average domain size D L of the separation part is determined.

3 . The compatibility evaluation method of a thermosetting resin composition according to claim 2 , wherein the step 1B is a step of obtaining the reflected electronic image of the cross section of the cured product of the thermosetting resin composition using the scanning electron microscope at an observation magnification of 50 to 200 times.

4 . A thermosetting resin composition comprising at least two kinds of resins and an inorganic filler, wherein:

the area ratio R w of the non-separation part obtained with a scanning electron microscope under the condition of an observation magnification of 100 times or 200 times in the compatibility evaluation method according to claim 1 is 50% or more, and

in the compatibility evaluation method according to the claim 2 , the condition of the observation magnification of the scanning electron microscope is 65 times, and the average domain size D L of the separation part, as obtained by averaging the domain size values of the domains having a size ranging from the 2nd to the 6th among the domains having a larger domain size counted from the larger domain size among the domains in the separation part observed in at least three fields of view, is 12011m or less.

5 . A prepreg comprising the thermosetting resin composition according to claim 4 .

6 . A resin film comprising the thermosetting resin composition according to claim 4 .

7 . A laminated plate comprising the prepreg according to claim 5 and a metal foil.

8 . A multilayer printed wiring board comprising the laminated plate according to claim 7 .

9 . A semiconductor package formed using the multilayer printed wiring board according to claim 8 .

10 . A multilayer printed wiring board comprising the prepreg according to claim 5 .

11 . A semiconductor package formed using the multilayer printed wiring board according to claim 10 .

12 . A multilayer printed wiring board comprising the resin film according to claim 6 .

13 . A semiconductor package formed using the multilayer printed wiring board according to claim 12 .