Void sealing in a dielectric material of a contact level of a semiconductor device comprising closely spaced transistors
In sophisticated semiconductor devices, a contact structure may be formed on the basis of a void positioned between closely spaced transistor elements wherein disadvantageous metal migration along the void may be suppressed by sealing the voids after etching a contact opening and prior to filling in the contact metal. Consequently, significant yield losses may be avoided in well-established dual stress liner approaches while, at the same time, superior device performance may be achieved.
1. A method, comprising:
forming an interlayer dielectric material above a plurality of closely spaced transistors formed in and above a semiconductor region of a semiconductor device so as to create a void between at least two adjacent ones of said closely spaced transistors;
forming a contact opening in said interlayer dielectric material, said contact opening extending to a contact region of said semiconductor region, said interlayer dielectric material comprising a stressed dielectric material for inducing a strain in said semiconductor region;
forming a metal confinement liner material at least partially on inner sidewalls of said contact opening to disconnect said void from said contact opening; and
filling said contact opening with a metal-containing material.
2. The method of claim 1 , wherein forming said contact opening comprises forming a first portion of said contact opening to connect to said void, forming said metal confinement liner material on inner sidewalls of said first portion and forming a second portion of said contact opening so as to extend to said contact region.
3. The method of claim 1 , wherein said contact opening is formed so as to extend to said contact region prior to forming said metal confinement liner material.
4. The method of claim 1 , wherein said metal confinement liner material comprises silicon dioxide.
5. The method of claim 4 , wherein said metal confinement liner material is formed by performing a sub-atmospheric chemical vapor deposition process.
6. The method of claim 1 , wherein forming said interlayer dielectric material further comprises forming a second stressed dielectric material above a second semiconductor region so as to induce a second type of strain in said second semiconductor region that differs from said strain.
7. The method of claim 1 , wherein a gate length of said closely spaced transistors is approximately 50 nm or less.
8. The method of claim 1 , wherein
said void extends along a transistor width direction between two adjacent ones of said plurality of transistors
and said metal confinement liner material suppresses metal migration from said contact opening into said void.
9. The method of claim 1 , wherein forming said interlayer dielectric material comprises forming said stressed dielectric material above said plurality of closely spaced transistors and forming at least one further dielectric material above said stressed dielectric material.
10. The method of claim 1 , wherein said metal confinement liner material comprises a dielectric material.
11. The method of claim 10 , wherein said metal confinement liner material is formed by a thermally activated chemical vapor deposition process.