Material composition is documented through Package Material Declaration Datasheet or PMDD and IPC 1752 documents. These documents are available per package and lead count and can be found on Cypress portal – www.cypress.com using part number search (search box located at top right corner of the page).
Cypress products normally have multiple assembly sites. The PMDD document includes the material composition of the package for each qualified manufacturing location.
If you are unable to retrieve the required information, please create a service request under the Quality documentation queue.