Small Business Tax Credits Improvement Act - Amends the Internal Revenue Code, with respect to the tax credit for the health insurance expenses of small employers, to: (1) expand eligibility for the credit to employers having up to 50 (currently, 25) full-time equivalent employees whose annual wages do not exceed $75,000 (currently, $50,000); (2) raise the employee threshold for triggering the phaseout of such credit from 10 to 20 full-time employees; (3) eliminate the requirement that employers contribute the same percentage of cost of each employee's health insurance and the cap limiting eligible employer contributions to average premiums paid to a state health care exchange; and (4) make such credit available to employee-owners and their dependents.