A method of forming a chip package includes providing a chip with a plurality of first bumps, wherein the plurality of first bumps has a first height. The method further includes providing a substrate with a plurality of second bumps, wherein the plurality of second bumps has a second height. The method further includes bonding the plurality of first bumps to the plurality of second bumps to form a first bump structure of the chip package, wherein the first bump structure has a standoff, wherein a ratio of a sum of the first height and the second height to the standoff is equal to or greater than about 0.6 and less than 1.