If I am working on a particular technology ,where can I find all the process parameters such as Cox,channel length modulation,mobility μn and μp,εox and tox. Is there any specific folder/path that I need to look into to find there values.
In IC design usually a .SCS file contains the parameters, but not these. These are Spice level 1 parameters, IC designers use BSIM4 parameters nowadays.
I would look in the DOC folders of all the info shared by the foundry. Usually should have info like mobility, Vth etc. I don't think you will find values for channel length modulation factor lambda though. As stated above it is usually a level 1 SPICE parameter. For advanced process a number of SCEs generally make up the lambda factor.
If you don't have access to a foundry's PDK, you could try the PTM non-foundry-specific, but process-specific SPICE files.
You'll find most of these parameters therein, from 180nm down to 7nm processes.