An electronic element mounting substrate is described, including a first insulating layer; a second insulating layer located below the first insulating layer in a first direction; a through conductor extending in the first direction from the first insulating layer through the second insulating layer; a first metal layer positioned on the first insulating layer, and including: a first portion positioned away from the through conductor; and a second portion in contact with the through conductor; and a second metal layer positioned between the first insulating layer and the second insulating layer, and including: a third portion in contact with the through conductor; and a fourth portion positioned away from the third portion by a first gap, wherein the second portion has a larger thickness than the first portion.

A package structure is provided. The package structure includes a chip structure and a first adhesive element partially covering the chip structure. The first adhesive element has a first portion and a second portion, and the first portion is spaced apart from the second portion. The first adhesive element has a first thermal conductivity. The package structure also includes a second adhesive element partially covering the chip structure. The second adhesive element has a second thermal conductivity, and the second thermal conductivity is higher than the first thermal conductivity.