Semiconductor memory device and method for driving the same

A semiconductor device, comprising:

• a first substrate including a first circuit unit and a first metal pad electrically connected to the first circuit unit;
• a second substrate including a second circuit unit and a second metal pad electrically connected to the second circuit unit, the second substrate being bonded with the first substrate to form a stack and being thinner than the first substrate and the second metal pad being electrically connected to the first metal pad;
• a gap provided between an outer peripheral portion of the first substrate and an outer peripheral portion of the second substrate;
• a first fill material provided in the gap and having a first viscosity, and
• a second fill material provided in the gap adjacent to the first fill material and having a second viscosity higher than the first viscosity.

A semiconductor device manufacturing method, comprising:

• forming a first layer on a first substrate;
• forming a second layer on a second substrate;
• bonding the first layer and the second layer to form a stack;
• after bonding the first layer and the second layer, filling a first fill material having a first viscosity in a gap located between an outer peripheral portion of the first substrate and an outer peripheral portion of the second substrate;
• and
• filling a second fill material having a second viscosity higher than the first viscosity in the gap so as to be adjacent to the first fill material after filling the first fill material in the gap.

A semiconductor device, comprising:

• a stack including;
• a first substrate;
• a second substrate provided above the first substrate;
• a first layer provided between the first substrate and the second substrate;
• a second layer provided between the first layer and the second substrate, the second layer being bonded with the first layer;
• a first gap portion provided between an outer peripheral portion of the first substrate and an outer peripheral portion of the second substrate, the first gap portion being filled with a first fill material provided in the gap and having a first viscosity;
• and
• a second gap portion provided between an outer peripheral portion of the first substrate and an outer peripheral portion of the second substrate, the second gap portion being filled with a second fill material provided in the gap adjacent to the first fill material and having a second viscosity higher than the first viscosity,
• wherein the first gap portion is provided between the first layer and the second gap portion.