Bonding quality test method, bonding quality test circuit, and memory device including bonding quality test circuit

A memory device, comprising:

• a first semiconductor layer that includes a plurality of memory cells and a bit line electrically connected to one or more of the plurality of memory cells;
• and
• a second semiconductor layer that includes a page buffer circuit electrically connected to the bit line through a bonding metal,
• wherein the page buffer circuit comprises:
• a switching circuit configured to provide an electrical connection between a sensing node and a bonding node, the bonding node corresponding to a first end of the bonding metal;
• a precharging circuit configured to provide a precharge voltage to the bit line and the sensing node when the precharging circuit is electrically connected to the bit line and the sensing node by the switching circuit;
• a latch circuit that includes a first node configured to provide a control output signal to the precharging circuit and a second node configured to have a voltage that is phase inverted with respect to a voltage of the control output signal;
• and
• a first transistor configured to provide an output signal according to the sensing node when the first transistor is electrically connected to the second node of the latch circuit.

A method of testing bonding of layers of a memory device, the layers comprising a first semiconductor layer on which a memory cell is formed and a second semiconductor layer bonded to the first semiconductor layer by a bonding metal and on which a peripheral circuit for driving the memory cell is formed, the method comprising:

• receiving an erase command for a block including a plurality of memory cells;
• determining whether a number of times of an operation cycle of the block has reached a predetermined operation limit cycle;
• electrically connecting, when the number of times of the operation cycle of the block reaches the operation limit cycle, a sensing node to a bonding node and providing a precharge voltage to the sensing node and the bonding node during a precharging period, the bonding node corresponding to a first end of the bonding metal;
• discharging the sensing node during a discharging period after the precharging period;
• and
• electrically connecting the bonding node and the bonding metal and electrically connecting the bonding node and the sensing node after the discharging period.