Method of forming field effect transistors with replacement metal gates and contacts and resulting structure
In a method for forming an integrated circuit (IC) structure, which incorporates multiple field effect transistors (FETs) with discrete replacement metal gates (RMGs) and replacement metal contacts (RMCs), gate cut trench(es) and contact cut trench(es) are formed at the same process level. These trench(es) are then filled at the same time with the same isolation material to form gate cut isolation region(s) for electrically isolating adjacent RMGs and contact cut isolation region(s) for electrically isolating adjacent RMCs, respectively. The selected isolation material can be a low-K isolation material for optimal performance. Furthermore, since the same process step is used to fill both types of trenches, only a single chemical mechanical polishing (CMP) process is needed to remove the isolation material from above the gate level, thereby minimizing gate height loss and process variation. Also disclosed herein is an IC structure formed according to the method.
1. An integrated circuit structure comprising:
a first transistor comprising:
a first semiconductor body having a first channel region positioned laterally between first source/drain regions; and
a first gate adjacent to the first channel region;
a second transistor comprising:
a second semiconductor body having a second channel region positioned laterally between second source/drain regions; and
a second gate adjacent to the second channel region;
metal contacts to the first source/drain regions and the second source/drain regions, wherein the metal contacts comprise at least a first metal contact to a first source/drain region of the first transistor and a second metal contact to a second source/drain region of the second transistor and wherein the first source/drain region of the first transistor is adjacent to the second source/drain region of the second transistor;
a first isolation region comprising a first trench filled with isolation material and positioned laterally between and immediately adjacent to the first gate and the second gate; and
a second isolation region comprising a second trench filled with the isolation material and positioned laterally between and immediately adjacent to the first metal contact and the second metal contact.
2. The integrated circuit structure of claim 1 , wherein the isolation material comprises a dielectric material with a dielectric constant that is no greater than 3.9.
3. The integrated circuit structure of claim 1 , wherein the isolation material comprises silicon oxycarbide.
4. The integrated circuit structure of claim 1 , wherein the first gate and the second gate comprise a first replacement metal gate and a second replacement metal gate, respectively.
5. The integrated circuit structure of claim 4 , wherein the first replacement metal gate has a first work function and the second replacement metal gate has a second work function that is different from the first work function.
6. The integrated circuit structure of claim 1 , wherein the first isolation region and the second isolation region are physically separated by a gate sidewall spacer.
7. An integrated circuit structure comprising:
a first transistor comprising:
multiple first semiconductor bodies, each first semiconductor body having a first channel region positioned laterally between corresponding first source/drain regions; and
a first gate adjacent to each first channel region;
a second transistor comprising:
multiple second semiconductor bodies, each second semiconductor body having a second channel region positioned laterally between corresponding second source/drain regions; and
a second gate adjacent to each second channel region;
metal contacts to the first source/drain regions and the second source/drain regions, wherein the metal contacts comprise at least a first metal contact to all first source/drain regions on a side of the first gate of the first transistor and a second metal contact to all second source/drain regions on a same side of the second gate of the second transistor;
a first isolation region comprising a first trench filled with isolation material and positioned laterally between and immediately adjacent to the first gate and the second gate; and
a second isolation region comprising a second trench filled with the isolation material and positioned laterally between and immediately adjacent to the first metal contact and the second metal contact.
8. The integrated circuit structure of claim 7 , wherein the isolation material comprises a dielectric material with a dielectric constant that is no greater than 3.9.
9. The integrated circuit structure of claim 7 , wherein the isolation material comprises silicon oxycarbide.
10. The integrated circuit structure of claim 7 , wherein the first gate and the second gate comprise a first replacement metal gate and a second replacement metal gate, respectively.
11. The integrated circuit structure of claim 10 , wherein the first replacement metal gate has a first work function and the second replacement metal gate has a second work function that is different from the first work function.
12. The integrated circuit structure of claim 7 , wherein the first isolation region and the second isolation region are physically separated by a gate sidewall spacer.
13. An integrated circuit structure comprising:
a first transistor comprising:
multiple first semiconductor bodies, each first semiconductor body having a first channel region positioned laterally between corresponding first source/drain regions; and
a first gate adjacent to each first channel region;
a second transistor comprising:
multiple second semiconductor bodies, each second semiconductor body having a second channel region positioned laterally between corresponding second source/drain regions; and
a second gate adjacent to each second channel region, wherein the second gate is in end-to-end alignment with the first gate such that an inner end of the first gate is adjacent to an inner end of the second gate;
a gate sidewall spacer laterally surrounding the first gate and the second gate such that the gate sidewall spacer is adjacent to an outer end and opposing sidewalls of the first gate and further adjacent to an outer end and opposing sidewalls of the second gate;
metal contacts to the first source/drain regions and the second source/drain regions, wherein the metal contacts comprise at least a first metal contact to all first source/drain regions on a side of the first gate of the first transistor and a second metal contact to all second source/drain regions on a same side of the second gate of the second transistor;
a first isolation region comprising a first trench filled with isolation material and positioned laterally between and immediately adjacent to the inner end of the first gate and the inner end of the second gate; and
a second isolation region comprising a second trench filled with the isolation material and positioned laterally between and immediately adjacent to the first metal contact and the second metal contact, wherein the gate sidewall spacer physically separates the first isolation region from the second isolation region.
14. The integrated circuit structure of claim 13 , wherein the isolation material comprises a dielectric material with a dielectric constant that is no greater than 3.9.
15. The integrated circuit structure of claim 13 , wherein the isolation material comprises silicon oxycarbide.
16. The integrated circuit structure of claim 13 , wherein the first gate and the second gate comprise a first replacement metal gate and a second replacement metal gate, respectively.
17. The integrated circuit structure of claim 16 , wherein the first replacement metal gate has a first work function and the second replacement metal gate has a second work function that is different from the first work function.