Taiwan Semiconductor Manufacturing Comp. Ltd.

Shau-Tsung Yu

Pei-Hung Chen

An-Min Chiang

Yeh-Jye Wann

Jyh-Cheng You

Yi-Jing Chu

An Min Chiang

Min-Yi Lin

Peng Yung-Sung

The present invention provides a method of manufacturing a read only memory that is code implanted late in the process after the first level metal thus reducing the turn around time to ship a customer order. The invention comprising the steps of: forming bit lines 125 and word lines 160 in a cell area 12A and MOS transistors in a peripheral area 13 of an integrated circuit; forming a first dielectric layer 300 over the surface; etching back the first dielectric layer 300 in the cell area; forming metal contacts 700 to the MOS devices in the peripheral areas 13; forming the second dielectric layer 320 over the resultant surface, storing the integrated circuit; and programming the ROM region 12A by the steps of forming a Code mask 340 with openings 340A from over portions of word lines in the cell area and implanting impurities through the openings 340A into substrate under the selected word lines 160 thereby programming the ROM device.

Post metal code engineering for a ROM

A method is described for forming P-channel field effect transistors having shallow source/drain junctions and improved reliability for CMOS circuits. The method involves forming both N-channel and P-channel FETs by alternate photoresist masking and ion implantation. The shallow junction self-aligned source/drain areas for P-channel FETs are formed by implanting boron difluoride (BF.sub.2) ions. In more conventional processing, the BF.sub.2 ions implanted in the P-channel FET gate electrodes during the source/drain implant results in outgassing of fluorine from the gate electrodes after the interlevel dielectric (ILD) layer is deposited. This can result in void formation, or delamination, at the interface between the gate electrode and the ILD. The current invention provides an improved process which uses a photoresist block-out mask to eliminate the implantation of the BF.sub.2.sup.+ ions in the P-channel FET gate electrodes during the formation of the self-aligned P.sup.+ source/drain regions. This prevents voids from forming at the gate electrode/ILD interface after the ILD layer is deposited and subsequent high-temperature processing steps are performed. The invention also reduces the enhanced boron diffusion in the P-FET gate oxide that can degrade the threshold voltage.

Method for preventing fluorine outgassing-induced interlevel dielectric

A method is described for forming P-channel field effect transistors having shallow source/drain junctions and improved reliability for CMOS circuits. The method involves forming both N-channel and P-channel FETs on the same substrate by alternate photoresist masking and ion implantation. The self-aligned source/drain areas for the P-channel FETs are formed by implanting boron difluoride (BF.sub.2) ions. In more conventional processing, the BF.sub.2 ions that are implanted in the P-channel FET gate electrodes during the source/drain implant results in out-gassing of fluorine from the gate electrodes after the interlevel dielectric (ILD) layer is deposited. This can result in void formation, or delamination, at the interface between the gate electrode and the ILD. The current invention provides an improved process which out-diffuses the fluorine atoms prior to depositing the ILD, and thereby prevents the formation of voids after the ILD is deposited and subsequent high-temperature process steps are performed.

Method for preventing delamination of interlevel dielectric layer over

A method for forming an aperture with a uniform void-free sidewall etch profile through a multi-layer insulator layer. There is formed upon a semiconductor substrate a multi-layer insulator layer which has a minimum of a first insulator layer and a second insulator layer. The second insulator layer is formed upon the first insulator layer. There is then etched through a first etch method a first aperture completely through the second insulator layer. The first etch method has: (1) a first perpendicular etch selectivity ratio for the second insulator layer with respect to the first insulator layer of at least about 4:1; and (2) a lateral:perpendicular etch selectivity ratio for the second insulator layer of from about 0.5:1 to about 1:1. The first aperture is then etched through a second etch method to form a second aperture completely through the second insulator layer and the first insulator layer. The second etch method has: (1) a second perpendicular etch selectivity ratio for the second insulator layer with respect to the first insulator layer of no greater than about 2:1; and (2) a lateral etch selectivity ratio of the second insulator layer with respect to the first insulator layer of from about 0.5:1 to about 1:1. The second aperture has a uniform void-free sidewall etch profile.

Growing community of inventors

Taipei, Taiwan

Shau-Tsung Yu