Integration　of　microfluidics　with　integrated　circuit　chip　is　a　promising　method　to　achieve　lab-on-a-chip　for　its　high-level　miniaturization　and　portability　in　application.　In　this　paper,　a　novel　approach　for　integration　of　complementary　metal-　oxide-semiconductor　image　sensor　and　microwell　array　using　the　3-D　wafer-level　chip　scale　package　(3-D　WLCSP)　technology　for　biodetector　is　presented.　The　key　process　including　silicon　microwell　array　fabricating,　wafer-level　bonding,　backside　grinding,　through-silicon　via　etching,　redistribution　layer,　and　hall　grid　array　formation　are　developed.　A　high-density　serpentine　electrical　circuit　is　integrated　on　the　backside　of　the　package　to　work　as　a　temperature　controller.　After　the　fabrication　process　optimization,　a　yield　rate　of　94.6%　is　obtained.　The　reliability　of　the　packages　is　characterized　by　thermal　cycling　and　highly　accelerated　stress　test　temperature　storage　tests,　and　the　results　show　a　good　package　level　reliability.　The　proposed　3-D　WLCSP　provides　a　low-cost　and　reliable　solution　for　the　fluidic　biodetector　integration.