US 6,725,119 B1 · Cleaning-apparatus line configuration and designing process therefor

Abstract

An objective of this invention is to provide a process for selecting rationally and quickly a wet process treatment in which an etchant can be shared based on a minimum preliminary investigation while eliminating cross contamination derived from a newly employed material, in a cleaning-apparatus line configuration in a process for manufacturing a silicon semiconductor device. In advance, an element which is suspected to cause cross contamination is added to an etchant used in a wet processing, a silicon substrate is immersed in the etchant, and then a correlation between a concentration of the element adhesively remaining still on the surface of the silicon substrate after the etchant is washed out with water and a concentration of the dissolved element in the etchant. On the basis of the result, the upper concentration limit of the element remaining by cross contamination is estimated when sharing the etchant. Then, with reference to the upper limit, whether deterioration of device properties occurs is evaluated to determine acceptability of etchant sharing.

Claims20

Dependent claims

A process for designing a cleaning-apparatus line configuration used in a wet process in a process for manufacturing a semiconductor device, comprising the steps of:

estimating a presumed concentration of dissolved contaminant elements accumulated in the same etchant used in a plurality of wet processes;
estimating a residual amount of the contaminant elements adhering to a substrate from the estimated concentration of dissolved contaminants;
evaluating sharing of the etchant in the plurality of wet processes when the estimated residual amount is less than a given reference value where device properties are affected;
and
conducting sharing of the etchant in a cleaning-apparatus line configuration used in a wet process on the basis of the decision.

2 more elements

A process for designing a cleaning-apparatus line configuration used in a wet process in a process for manufacturing a semiconductor device, wherein on the basis of results obtained by conducting, for various materials constituting the semiconductor device, the following preliminary tests:

(a) a dissolution test for determining whether the materials are dissolved in an etchant used in two or more wet processes in the manufacturing process;
(b) a dissolution rate test assessing the etchant dissolving the material for the amount of the dissolved material per a unit area of the material and a unit time;
(c) an adhesion property test comprising the steps of dissolving ion or molecule species generated when dissolving the material, to a given concentration in the etchant;
immersing a clean substrate in the given concentration solution for a given time;
then removing the etchant by washing with a usual procedure;
and determining presence of adhering residual elements derived from the material on the substrate surface;
(d) an adhesion-property concentration dependency test where for an element derived from the material which has been determined to remain by adhesion in the adhesion property test, a correlation is determined between the concentration of the dissolved element in the etchant and its surface density adhering to the substrate surface;
(e) an effective adhesion-inhibitor selection test comprising the step of determining a re-adhesion inhibiting agent which after being added to the etchant, forms a complex or compound with the ion or molecular species of the element derived from the material which has been determined to remain by adhesion in the adhesion property test, to reduce the adhesional residue,
sharing an etchant used in a wet process where the etchant is inevitably in contact with the material between the process and another wet process is evaluated in a manner that considering the following selection criteria:
(i) an etchant which is determined not to dissolve the material in the dissolution test in (a);
(ii) an etchant which is determined that there are no residues by adhesion in the adhesion property test in (c);
(iii) an etchant which has been determined that there are residues by adhesion in the adhesion property test in (c) and which is determined that an estimated adhesion surface density is less than a given contaminant surface density limit within which the properties of the semiconductor device are not deteriorated, by calculating an estimated concentration of dissolved ion or molecular species of an element derived from the material accumulated by dissolution in the etchant when processing a given number of substrates according to the structure of the semiconductor device, based on a dissolution rate obtained in the dissolution rate test in (b) and determining the estimated adhesion surface density from the estimated dissolution concentration, based on a correlation between the dissolution concentration in the etchant and the surface density of the residues adhering to the substrate surface, that is determined in the adhesion-property concentration dependency test in (d);
(iv) an etchant containing a re-adhesion inhibitor, which is evaluated that the estimated adhesion surface density is equal to or higher than the contaminant surface density limit and is evaluated in a re-estimation that an estimated adhesion surface density becomes lower than the contaminant surface density limit by adding the re-adhesion inhibitor which is determined to be effective in the effective adhesion-inhibitor selection test in (e),
an etchant meeting the selection criteria (i) to (iii) can be shared;
an etchant further meeting the selection criterion (iv) can be shared after adding the re-adhesion inhibitor determined to be effective, or otherwise a remaining etchant can be shared only in wet processes where the etchant is not inevitably in contact with a material which may be a source of an element suspected to cause deterioration of the properties of the semiconductor device, and
according to the evaluation, etchant sharing is employed in a cleaning-apparatus line configuration used in a wet process.

13 more elements

A process for designing a cleaning-apparatus line configuration where a wafer on which a semiconductor device is formed is cleaned with an etchant in a process for manufacturing a semiconductor device, wherein the manufacturing process comprises a step of cleaning the wafer on which a material used in the semiconductor device is exposed, with a given etchant, and comprising the steps of:

estimating a dissolution concentration of the material exposed on the wafer surface in the etchant;
determining a surface density of the material adhering to the wafer when immersing the wafer in the etchant in which the material is dissolved at the estimated dissolution concentration for a given period;
evaluating that the etchant can be shared in another cleaning step when the adhesion surface density is lower than a given contaminant surface density limit defined according to whether the adhesion surface density affects the properties of the semiconductor device;
evaluating that the etchant cannot be shared in another cleaning step when the adhesion surface density is higher than the given contaminant surface density limit;
and
designing a cleaning-apparatus line configuration according to the evaluation results.

3 more elements

Dependencies are inferred from the claim text.

Cleaning-apparatus line configuration and designing process therefor

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Cleaning-apparatus line configuration and designing process therefor

Life of this patent

Abstract

Claims20