N.C. Gen. Stat. § 66-57.1
Any provision in an employment agreement which provides that the employee shall assign or offer to assign any of his rights in an invention to his employer shall not apply to an invention that the employee developed entirely on his own time without using the employer's equipment, supplies, facility or trade secret information except for those inventions that (i) relate to the employer's business or actual or demonstrably anticipated research or development, or (ii) result from any work performed by the employee for the employer. To the extent a provision in an employment agreement purports to apply to the type of invention described, it is against the public policy of this State and is unenforceable. The employee shall bear the burden of proof in establishing that his invention qualifies under this section.
N.C. Gen. Stat. § 66-57.1