Semiconductor device and manufacturing method for semiconductor device to reduce the lithography masks
View Patent ↗Semiconductor device and manufacturing method for reducing the number of required lithography masks added to the nonvolatile memory in the standard CMOS process to shorten the production period and reduce costs. In a split-gate memory cell with silicided gate electrodes utilizing a sidewall structure, a separate auxiliary pattern is formed adjoining the selected gate electrodes. A contact is set on a wiring layer self-aligned by filling side-wall gates of polysilicon in the gap between the electrodes and auxiliary pattern. The contact may overlap onto the auxiliary pattern and device isolation region, in an optimal design considering the size of the occupied surface area. If the distance to the selected gate electrode is x, the ONO film deposit thickness is t, and the polysilicon film deposit thickness is d, then the auxiliary pattern may be separated just by a distance x such that x<2×(t+d).
1. A semiconductor manufacturing method for a memory cell array of a semiconductor device, comprising:
depositing a first conductive film over a semiconductor substrate and forming a first gate electrode and an auxiliary pattern electrically isolated from the first gate electrode;
forming a first insulator film over the first gate electrode, the auxiliary pattern, and the semiconductor substrate;
depositing a second conductive film over the first insulator film and, by etching back the second conductive film, respectively forming a side wall electrode along the first gate electrode interposing the first insulator film between the side wall electrode and the first gate electrode, and forming an extended electrode on a circumference of the auxiliary pattern as said extended electrode merges with side wall electrode;
exposing the upper surface of the auxiliary pattern and the first gate electrode by stripping away the first insulator film formed over the first gate electrode and the auxiliary pattern;
siliciding the upper surface of the first gate electrode, and the surface of the side wall electrode;
forming a second insulator film over the auxiliary pattern and the extended electrode;
forming at least one or more contact holes on the second insulator film and, exposing the extended electrode at the forming of one of the contact holes; and
forming contacts in the contact holes.
2. A semiconductor manufacturing method for a semiconductor device according to claim 1 , wherein the surface of the semiconductor substrate is subjected to silicidation.
3. A semiconductor manufacturing method for a semiconductor device according to claim 1 , wherein the first insulator film is a multilayer film formed from multiple different materials.
4. A semiconductor manufacturing method for a semiconductor device according to claim 1 , wherein the first insulator film includes a charge trapping film.
5. A semiconductor manufacturing method for a semiconductor device according to claim 4 , wherein the charge trapping film is a silicon nitride film.
6. A semiconductor manufacturing method for a semiconductor device according to claim 1 , wherein the auxiliary pattern is formed at a position closer than a distance of twice the sum of the first insulator film thickness and the second conductive film thickness from the side surface of the first gate electrode.
7. A semiconductor manufacturing method for a semiconductor device according to claim 1 , wherein the auxiliary pattern includes at least a first auxiliary pattern and a second auxiliary pattern and, the first auxiliary pattern is formed at a position from the side surface of the first gate electrode closer than a distance of twice the sum of the first insulator film thickness and the second conductive film thickness, and the second auxiliary pattern is formed at a position from the side surface of the first auxiliary pattern closer than a distance twice the sum of the first insulator film thickness and the second conductive film thickness.
8. A semiconductor manufacturing method for a semiconductor device according to claim 7 , wherein the second auxiliary pattern is formed at a position closer than a distance twice the sum of the first insulator film thickness and the second conductive film thickness, from the side surface of the first gate electrode.