Method for manufacturing semiconductor device
View Patent ↗A contact hole, after hole etching, is subjected to light etching using a process gas containing a fluorocarbon-based gas and oxygen, with the oxygen being enriched, under condition without applying bias. Then, reaction products ( 5 ) having C—F bond and adhered to an interior of a hole ( 3 ) are removed using plasma treatment. After that, deposits ( 4 ) that have been left at a hole bottom are removed by wet processing. Then, a conductive material is buried in the hole to form a contact plug ( 7 ).
1. A method for manufacturing a semiconductor device, comprising:
forming an interlayer insulating film on a substrate which is formed with a lower conductor;
forming a contact hole in the interlayer insulating film;
performing light etching in the contact hole, using a process gas containing a fluorocarbon-based gas and oxygen, with the oxygen being enriched, under condition without applying bias, a flow ratio between the fluorocarbon-based gas and oxygen in the process gas being in a range from 1:99 to 1:198;
performing oxygen plasma treatment after purging the process gas;
washing an interior of the contact hole using a wash solution; and
after drying, forming a contact plug by burying a conductor in the contact hole.
2. The method for manufacturing a semiconductor device according to claim 1 , wherein an aspect ratio of the contact hole to be formed is equal to or more than 10.
3. The method for manufacturing a semiconductor device according to claim 1 , wherein the light etching and the oxygen plasma treatment are successively performed in the same chamber.
4. The method for manufacturing a semiconductor device according to claim 1 , wherein the forming of the contact hole comprises performing hard mask etching using a resist mask.
5. The method for manufacturing a semiconductor device according to claim 1 , wherein the performing of the light etching of the contact hole comprises forming a reaction product having a C—F bond in the contact hole, and the performing of the oxygen plasma treatment comprises cleaving the C—F bond to turn a property of the contact hole from a hydrophobic property into a hydrophilic property.
6. The method for manufacturing a semiconductor device according to claim 1 , wherein the interlayer insulating film comprises silicon oxide.
7. The method for manufacturing a semiconductor device according to claim 1 , wherein the wash solution comprises dilute hydrofluoric acid solution.
8. The method for manufacturing a semiconductor device according to claim 1 , further comprising:
applying the contact hole with an ultrasonic wave concurrently with the washing of the interior of the contact hole.
9. The method for manufacturing a semiconductor device according to claim 1 , wherein the fluorocarbon-based gas is selected from a group consisting of CF 4 , CHF 3 and C 4 F 8 .
10. The method for manufacturing a semiconductor device according to claim 1 , wherein the performing of the light etching comprises in a chamber, performing the light etching by flowing the process gas containing the fluorocarbon-based gas and oxygen into the chamber, with the oxygen being enriched, under condition without applying bias.
11. A method of manufacturing a semiconductor device, comprising:
forming a contact hole in an interlayer insulating film;
performing light etching in the contact hole, using a process gas including a fluorocarbon-based gas and oxygen, with the oxygen being enriched, under condition without applying bias, a flow ratio between the fluorocarbon-based gas and oxygen in the process gas being in a range from 1:99 to 1:198;
purging the process gas from the chamber;
performing oxygen plasma treatment in the purged chamber;
washing an interior of the contact hole using a wash solution; and
after drying, forming a contact plug by burying a conductor in the contact hole.