Semiconductor device
AssigneeFuji Electric Co., Ltd.
InventorYoshiaki Toyoda
Life of this patent
Estimating the term…
Abstract
A low cost, small scale semiconductor device including a trimming circuit having a fuse resistor is disclosed. By a trimming circuit being configured of a MOSFET, a protection circuit, and a fuse resistor, it is possible to carry out a change from an open circuit state to a short circuit state by fusing the fuse resistor. Also, by the protection circuit and fuse resistor configuring the trimming circuit being formed in a two layer structure, it is possible to reduce the size of the trimming circuit, and thus it is possible to provide a low cost, small scale semiconductor device having a trimming circuit that occupies a small area.
Claims9
A semiconductor device comprising a trimming circuit including:
- a constant current circuit;
- a fuse resistor, one end of which is connected to the constant current circuit;
- a trimming pad connected to a connection point connecting the constant current circuit and the one end of the fuse resistor;
- a protection resistor of which one end is connected to the connection point;
- a protection diode, a cathode of which is connected to the other end of the protection resistor:
- a MOS transistor, a gate of which is connected to the other end of the protection resistor;
- and
- a ground to which are connected the other end of the fuse resistor and an anode of the protection diode, wherein
- the fuse resistor, protection resistor, and protection diode are formed of a polysilicon layer disposed across a first dielectric on a semiconductor substrate,
- wherein a first layer polysilicon layer in which the fuse resistor is formed is disposed on the first dielectric, a second layer polysilicon layer in which the protection resistor and protection diode are formed is disposed across a second dielectric on the first layer polysilicon layer, and a third dielectric is disposed on the second layer polysilicon layer.
A semiconductor device comprising a trimming circuit including:
- a constant current circuit;
- a fuse resistor, one end of which is connected to the constant current circuit;
- a trimming pad connected to a connection point connecting the constant current circuit and the one end of the fuse resistor;
- a protection resistor of which one end is connected to the connection point;
- a protection diode, a cathode of which is connected to the other end of the protection resistor;
- a MOS transistor, a gate of which is connected to the other end of the protection resistor;
- and
- a ground to which are connected the other end of the fuse resistor and an anode of the protection diode, wherein
- the fuse resistor, protection resistor, and protection diode are formed of a polysilicon layer disposed across a first dielectric on a semiconductor substrate,
- wherein a first layer polysilicon layer in which the protection resistor and protection diode are formed is disposed on the first dielectric, and a second layer polysilicon layer in which the fuse resistor is formed is disposed across a second dielectric on the first layer polysilicon layer.
Dependencies are inferred from the claim text.