Abstract: A power MOSFET includes a substrate, a dielectric layer, solder balls, first and second patterned-metal layers. The substrate includes an active surface, a back surface, a source region and a gate region on the active surface, and a drain region on the back surface. The first patterned-metal layer disposed on the active surface includes a source electrode, a gate electrode, a drain electrode and a connecting trace. The source and gate electrodes electrically connect the source and gate regions. The connecting trace located at an edge of the substrate electrically connects the drain electrode. The dielectric layer disposed on the active surface exposes the first patterned-metal layer. The second patterned-metal layer includes UBM layers covering the source, gate and drain electrodes and a connecting metal layer covering the connecting trace and extending to the edge to electrically connect the drain region. The solder balls are disposed on the UBM layers.

Abstract: A power MOSFET includes a substrate, a dielectric layer, solder balls, first and second patterned-metal layers. The substrate includes an active surface, a back surface, a source region and a gate region on the active surface, and a drain region on the back surface. The first patterned-metal layer disposed on the active surface includes a source electrode, a gate electrode, a drain electrode and a connecting trace. The source and gate electrodes electrically connect the source and gate regions. The connecting trace located at an edge of the substrate electrically connects the drain electrode. The dielectric layer disposed on the active surface exposes the first patterned-metal layer. The second patterned-metal layer includes UBM layers covering the source, gate and drain electrodes and a connecting metal layer covering the connecting trace and extending to the edge to electrically connect the drain region. The solder balls are disposed on the UBM layers.

Abstract: A power MOSFET includes a substrate, a dielectric layer, solder balls, first and second patterned-metal layers. The substrate includes an active surface, a back surface, a source region and a gate region on the active surface, and a drain region on the back surface. The first patterned-metal layer disposed on the active surface includes a source electrode, a gate electrode, a drain electrode and a connecting trace. The source and gate electrodes electrically connect the source and gate regions. The connecting trace located at an edge of the substrate electrically connects the drain electrode. The dielectric layer disposed on the active surface exposes the first patterned-metal layer. The second patterned-metal layer includes UBM layers covering the source, gate and drain electrodes and a connecting metal layer covering the connecting trace and extending to the edge to electrically connect the drain region. The solder balls are disposed on the UBM layers.

Abstract: A power switch device includes a transistor and an ESD protection circuit. The transistor includes a source, a drain, and a gate, wherein a well region is disposed between the source and the drain. One end of the ESD protection circuit is coupled to the gate and another end thereof is coupled to the well region so as to form a protection circuit between the gate and the source and between the gate and the drain simultaneously.

Abstract: A power MOSFET includes a substrate, a dielectric layer, solder balls, first and second patterned-metal layers. The substrate includes an active surface, a back surface, a source region and a gate region on the active surface, and a drain region on the back surface. The first patterned-metal layer disposed on the active surface includes a source electrode, a gate electrode, a drain electrode and a connecting trace. The source and gate electrodes electrically connect the source and gate regions. The connecting trace located at an edge of the substrate electrically connects the drain electrode. The dielectric layer disposed on the active surface exposes the first patterned-metal layer. The second patterned-metal layer includes UBM layers covering the source, gate and drain electrodes and a connecting metal layer covering the connecting trace and extending to the edge to electrically connect the drain region. The solder balls are disposed on the UBM layers.

Abstract: A power switch device includes a transistor and an ESD protection circuit. The transistor includes a source, a drain, and a gate, wherein a well region is disposed between the source and the drain. One end of the ESD protection circuit is coupled to the gate and another end thereof is coupled to the well region so as to form a protection circuit between the gate and the source and between the gate and the drain simultaneously.

Abstract: A method of forming a power MOSFET is described. An epitaxial layer of first conductivity type is formed on a substrate of first conductivity type. A body layer of second conductivity type is formed in the epitaxial layer. A plurality of mask patterns are formed on the substrate. A plurality of trenches are formed in the body layer and the epitaxial layer between the mask patterns. An oxide layer is formed on surfaces of the trenches. A conductive layer is formed in the trenches. A trimming process is performed to the mask patterns to reduce the line width of each mask pattern. Two source regions of first conductivity type are formed in the body layer beside each trench by using the trimmed mask patterns as a mask. A plurality of dielectric patterns are formed on the conductive layer and between the trimmed mask patterns. The trimmed mask patterns are removed.

Abstract: A power MOSFET is described. A trench is in a body layer and an epitaxial layer. An isolation structure is on the substrate at one side of the trench. An oxide layer is on the surface of the trench. A first conductive layer fills the trench and extends to the isolation structure. A dielectric layer is on the first conductive layer and isolation structure and has an opening exposing the first conductive layer. At least one source region is in the body layer at the other side of the trench. A second conductive layer is on the dielectric layer and electrically connected to the source region while electrically isolated from the first conductive layer by the dielectric layer. A third conductive layer is on the dielectric layer and electrically connected to the first conductive layer through the opening of the dielectric layer. The second and third conductive layers are separated.

Abstract: A power MOSFET is described. A trench is in a body layer and an epitaxial layer. An isolation structure is on the substrate at one side of the trench. An oxide layer is on the surface of the trench. A first conductive layer fills the trench and extends to the isolation structure. A dielectric layer is on the first conductive layer and isolation structure and has an opening exposing the first conductive layer. At least one source region is in the body layer at the other side of the trench. A second conductive layer is on the dielectric layer and electrically connected to the source region while electrically isolated from the first conductive layer by the dielectric layer. A third conductive layer is on the dielectric layer and electrically connected to the first conductive layer through the opening of the dielectric layer. The second and third conductive layers are separated.

Abstract: A method of forming a power MOSFET is described. An epitaxial layer of first conductivity type is formed on a substrate of first conductivity type. A body layer of second conductivity type is formed in the epitaxial layer. A plurality of mask patterns are formed on the substrate. A plurality of trenches are formed in the body layer and the epitaxial layer between the mask patterns. An oxide layer is formed on surfaces of the trenches. A conductive layer is formed in the trenches. A trimming process is performed to the mask patterns to reduce the line width of each mask pattern. Two source regions of first conductivity type are formed in the body layer beside each trench by using the trimmed mask patterns as a mask. A plurality of dielectric patterns are formed on the conductive layer and between the trimmed mask patterns. The trimmed mask patterns are removed.