You will pay the tax either way. (Only in an RRSP can you get exemptions.)
The purpose of a tax free account is to get dividends tax free. The US does not recognize this so they will withhold taxes. Defeats the purpose.
Financial advisers counsel investors to avoid holding dividend-paying foreign stocks in a TFSA due to the non-resident withholding tax levied. This tax, which is collected before dividends are paid to non-residents, is not recoverable, effectively reducing the return rate. The standard dividend withholding tax rate for U.S. stocks is 30 per cent, but if you file a U.S. Internal Revenue Service Form W-8BEN with your broker, the rate is lowered to 15 per cent.