We, for the first time, present novel test patterns and conclusive on-chip data indicating that the variation of coupling capacitance, ${Delta}C_C$ by crosstalk can be larger than static coupling capacitance, $C_C$. The test chip is fabricated using a generic 150 nm CMOS technology with 7 level metallization. It is also shown that ${Delta}C_C$ is strongly dependent on the phase of aggressive lines. For antiphase crosstalk ${Delta}C_C$ is always larger than $C_C$ while for in-phase crosstalk $D_{Delta}C_C$is smaller than $C_C$.