Method for fabricating substrate structure and substrate structure fabricated by using the method

A substrate structure comprising:

• a first substrate including a first base substrate, and a first device region on the first base substrate;
• and
• a second substrate including a second device region on the first device region, and a second base substrate on the second device region, a bottom surface of the second device region being directly bonded to an upper surface of the first device region,
• wherein the first device region and the second device region are electrically connected to each other,
• the first device region and the second device region each include a device pattern,
• a sidewall of the second device region includes an inclined surface that is acute with respect to the upper surface of the first device region,
• the sidewall of the second device region includes a continuous profile with a sidewall of the first device region.

A substrate structure comprising:

• a first substrate including first and second surfaces opposite each other, and a first device region at the first surface;
• and
• a second substrate including third and fourth surfaces opposite each other, and a second device region formed at the third surface, the third surface of the second substrate being directly bonded to the first surface of the first substrate,
• wherein the first device region and the second device region are electrically connected to each other,
• the first device region and the second device region each include a device pattern, and
• widths of the first and second device regions decrease in a direction from the second surface of the first substrate toward the fourth surface of the second substrate.