Taiwan Semiconductor Manufacturing Comp. Ltd.

Wen-Cheng Chang

Sen-Fu Chen

Bao-Ru Yang

Shung-Jen Yu

Yu-Ming Tsui

Heng-Hsin Liu

Chih-Heng Shen

Hua-Yu Yang

Sen Fu Chen

Po-Tau Chu

Jie Shing Wu

Sheng-Yih Ting

A high-sheet-resistance polysilicon resistor for integrated circuits is achieved by using a two-layer polysilicon process. After forming FET gate electrodes and capacitor bottom electrodes from a polycide layer, a thin interpolysilicon oxide (IPO) layer is deposited to form the capacitor interelectrode dielectric. A doped polysilicon layer and an undoped polysilicon layer are deposited and patterned to form the resistor. The doped polysilicon layer is in-situ doped to minimize the temperature and voltage coefficients of resistivity. Since the undoped polysilicon layer has a very high resistance (infinite), the resistance is predominantly determined by the doped polysilicon layer. The doped polysilicon layer can be reduced in thickness (less than 1000 Angstroms) to further increase the sheet resistance for mixed-mode circuits, while the undoped polysilicon layer allows contact openings to be etched in an insulating layer over the resistor without overetching the thin doped polysilicon layer and damaging the underlying IPO layer.

Method for making high-sheet-resistance polysilicon resistors for integrated circuits

Device layouts are described which increase the photon current of a metal oxide semiconductor image sensor. The metal oxide semiconductor can be NMOS, PMOS, or CMOS. The key part of the photon current of the image sensors comes from the depletion region at the PN junction between the drain region and the substrate material. The layouts used significantly increase the area of this depletion region illuminated by a stream of photons. The layouts have a drain region which takes the shape of a number of parallel fingers perpendicular to the gate electrode, a number of parallel fingers parallel to the gate electrode, or a spiral. The drain regions of these layouts significantly increase the area of the drain depletion region illuminated by a stream of electrons.

Layout of an image sensor for increasing photon induced current

Method for making high-sheet-resistance polysilicon resistors for

The polymeric residues which remain after the plasma-enhanced subtractive etching of polycrystalline layers in reactive halogen-containing gases are removed by a combination ashing in oxygen gas and subsequent removal with an organic solvent.

Method for polymer removal after etching

A process for creating field oxide isolation for the micron and sub-micron devices in the high density integrated circuits has been developed. The junction leakage problem resulted from the trenches in the substrate formed after the removal of the silicon nitride mask, is avoided. The encroachment of the 'bird's beak' into the small active device region is also minimized by this invention. These goals are accomplished by the addition of a polysilicon or amorphous silicon refill layer in the trenches after the removal of the silicon nitride oxidation mask in the isolation region, prior to field oxide oxidation process.

Substrate isolation process to minimize junction leakage

A protective cap of dielectric material is deposited by plasma-enhanced chemical vapor deposition on the surface of electrical bonding pads of semiconductor integrated circuits prior to deposition of the final passivation layer. The protective cap serves to isolate the pad surface from electrochemical or other interaction with the etching solution used to open contact holes through the passivation layer. This prevents the formation of surface damage and residues on the pad which lead to yield and reliability problem with integrated circuits.

Growing community of inventors

Hsin-Chu, Taiwan

Wen-Cheng Chang