Method and system for advanced process control in an etch system by gas flow control on the basis of CD measurements
View Patent ↗By controlling the flow rate of one or more gaseous components of an etch ambient during the formation of metal lines and vias on the basis of feedback measurement data from critical dimensions, process variations may be reduced, thereby enhancing performance and reliability of the respective metallization structure.
1. A control system, comprising:
one or more etch tools configured to etch a first and a second substrate in a first and a second etch atmosphere each comprising at least one gaseous component to form features on said first and second substrates, wherein at least one of said features is a via formed in a dielectric layer to expose an underlying metal region;
at least one metrology unit configured to measure electrical data representative of a characteristic of the features formed on the substrates, wherein at least one of said features is the via;
a control section that is operatively connected to said etch tools and said at least one metrology unit, the control section being configured to:
determine at least one flow rate of a supply of said at least one gaseous component to said one or more etch tools configured to etch the first substrate to form a first via in a first dielectric layer to expose a first metal region on said first substrate;
receive, from said at least one metrology unit, feedback information indicative of the measured electrical data representative of the characteristic of the first via formed on the first substrate; and
provide, to said one or more etch tools, signaling indicating a modified value of said at least one flow rate of the supply of said at least one gaseous component for etching the second substrate in the second etch atmosphere to form a second via in a second dielectric layer to expose a second metal region on said second substrate, wherein the modified value is determined based on the feedback information.
2. The control system of claim 1 , wherein said control section receives, from said at least one metrology unit, measurement data of critical dimensions of said first via and to modify said at least one flow rate on the basis of said measurement data and a target value for said critical dimension.
3. The control system of claim 1 , wherein said control section determines a sensitivity indicating a correlation between said at least one flow rate and said characteristic of said first via on said first substrate.
4. The control system of claim 3 , wherein said control section modifies said at least one flow rate using said determined sensitivity and a measured value of said characteristic for determining an updated flow rate for etching said second substrate.
5. The control system of claim 4 , wherein said control section determines a deviation of said measured value from a target value for said characteristic and uses said deviation and said sensitivity to determine said updated flow rate.
6. The control system of claim 5 , wherein said control section is selects said correlation as a linear relationship.