The Illinois Secretary of State does offer free, online UCC searches at http://www.ilsos.gov/uccsearch/, but the free search results are uncertified. The Secretary of State requires a UCC-11 form and payment for certified search results.
As an alternative to submitting search requests to the Secretary of State directly, you might consider using a third party to conduct your UCC and other lien searches. Several companies offer comprehensive UCC lien search services, such as Corporation Service Company, Wolters Kluwer, Infinity Professional Services Group Inc., Advanced Corporation Agents and many more.