United Microelectronics Corp.

D Y Wu

Water Lur

Ming-Tsung Liu

Jeffrey Wang

Wen Yang Chen

The invention describes a non-trenched buried contact for local interconnections in VLSI devices and provides a method for forming the non-trenched buried contact. By using trenched isolation and a trench polysilicon gate structure the buried contact process can be implemented so that there are no unwanted trenches formed in the area of the buried contact. The invention permits excellent planarization of the device prior to pre-metal dielectric and metal deposition.

Non-trenched buried contact for VLSI devices

A new method of planarizing an integrated circuit is achieved. The dielectric layers between the conductive layers of an integrated circuit are formed and planarized via A first silicon oxide layer is deposited over the metal layer. This is covered with a spin-on-glass layer. This layer is dried by baking. The spin-on-glass layer is now fully cured. The cured spin-on-glass layer is now ion implanted under the conditions of between about 1E15 to 1E17 atoms/cm.sup.2 and energy between about 50 to 100 KeV. A silicon oxide layer is deposited thereover. Via openings are now made through the silicon oxide layers and the spin-on-glass layer and filled with metal. This results in excellent planarity with no poisoned via problems. Most importantly, this method can be used for submicron technologies having conductor lines which are spaced from one another by submicron feature size and can be processed without the use of an etch-back process for the cured spin on and glass layer.

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Hsin-chu, Taiwan

D Y Wu