Full payment is required to be made before the due date for the tax return. Failure to do so will result in interest and penalties.
One way to do this is to make estimated tax payments during the course of the year. For individuals, these payments are usually made on April 15th, June 15th, September 15th of the current tax year & January 15th of the following calendar year.
Dates sometimes vary if the day falls on a holiday or weekend, so check the IRS website to confirm the dates each year.