US 12,170,310 B2
Integrated circuits including composite dielectric layer
Guruvayurappan S. Mathur, Plano, TX (US); Abbas Ali, Plano, TX (US); Poornika Fernandes, Murphy, TX (US); Bhaskar Srinivasan, Allen, TX (US); Darrell R. Krumme, Waxahachie, TX (US); Joao Sergio Afonso, Allen, TX (US); Shih-Chang Chang, Allen, TX (US); and Shariq Arshad, Parker, TX (US)
Assigned to Texas Instruments Incorporated, Dallas, TX (US)
Filed by TEXAS INSTRUMENTS INCORPORATED, Dallas, TX (US)
Filed on Jun. 26, 2019, as Appl. No. 16/453,796.
Prior Publication US 2020/0411633 A1, Dec. 31, 2020
Int. Cl. H01L 21/8238 (2006.01); H01L 21/336 (2006.01); H01L 21/8234 (2006.01); H01L 27/06 (2006.01); H01L 49/02 (2006.01)
CPC H01L 28/40 (2013.01) [H01L 27/0629 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of manufacturing an integrated circuit, comprising the steps of:
providing a semiconductor substrate including:
an isolation layer disposed on or over the semiconductor substrate; and
a first conductive plate located over the isolation layer; and
forming a composite dielectric layer over the first conductive plate, the forming including:
forming a first sublayer and a second sublayer each having a substantially same first chemical composition;
forming a third sublayer between the first and second sublayers, the third sublayer having a second different chemical composition including silicon, nitrogen and hydrogen; and
forming a second conductive plate located directly on the composite dielectric layer;
forming a second dielectric layer on the second conductive plate;
depositing a pre-metal dielectric (PMD) layer over the composite dielectric layer and the second dielectric layer, the PMD layer comprising boron phosphorus silicate glass and having a top side;
forming a plurality of contacts, the forming of the plurality of contacts comprising:
performing a first dry etch process with a first etch chemistry compatible to etch through the PMD layer and the second sublayer, wherein the first etch chemistry comprises tetrafluromethane/oxygen (CF4/O2) plasmas with admixed argon (Ar), hydrogen (H2) and perflurocyclopentene (C5F8), and wherein the third sublayer functions as an etch stop layer for the first etch chemistry;
performing a second dry etch process with a second etch chemistry compatible to etch through the third sublayer, wherein the second etch chemistry comprises tetrafluromethane (CF4) plasma with admixed argon and difluromethane (CH2F2), and wherein the first sublayer functions as an etch stop layer for the second etch chemistry;
resuming the first dry etch process with the first etch chemistry compatible to etch through the first sublayer to form a plurality of contact openings; and
filling the plurality of contact openings with a conductive material;
wherein forming the third sublayer includes providing silane at a flow rate in a range between 175 sccm and 210 sccm, ammonia at a flow rate in a range between 320 and 480 sccm, and nitrogen at a flow rate in a range between 6400 and 9600 sccm, and providing high-frequency RF power of about 230 W, with a substrate temperature of about 350° C. during forming of the first, second and third sublayers, and the third sublayer includes hydrogen bonded about equally with silicon and with nitrogen.