The　work　aims　to　systematically　improve　the　roughening　performance　of　electrolytic　copper　foil　with　a　composite　additive　of　sodium　molybdate,　sodium　tungstate,　and　hydroxyethyl　cellulose　(HEC).　Electrolytic　copper　foil　is　widely　used　in　electronic　devices,　especially　printed　circuit　boards　(PCBs),　with　key　performance　requirements　including　high　peel　strength　and　low　surface　roughness.　In　order　to　optimize　these　properties,　direct　current　electroplating　was　used　in　a　copper　sulfate　electroplating　system　and　various　characterization　techniques　were　employed　such　as　scanning　electron　microscopy　(SEM),　laser　confocal　microscopy　(LCM),　and　peel　strength　testing.　The　microstructure　of　the　rough　copper　foil　was　analyzed　in　detail,　and　the　impact　of　various　additives　on　the　roughening　effect　was　analyzed　through　orthogonal　experiments　and　range　analysis.　The　addition　of　sodium　molybdate　and　HEC　alone　significantly　refined　the　grain　structure　of　the　copper　foil　surface,　improving　its　smoothness　and　uniformity.　In　contrast,　sodium　tungstate　mainly　improved　the　peel　strength　and　had　a　relatively　small　impact　on　grain　refinement.　The　composite　additive　showed　significant　synergistic　effects,　effectively　optimizing　the　microstructure　of　copper　foil　under　different　concentration　combinations.　Specifically,　the　concentrations　of　40　mg/L　sodium　molybdate,　30　mg/L　sodium　tungstate,　and　8　mg/L　HEC　produced　the　best　roughening　results,　with　the　lowest　surface　roughness　(Rz=1.24　µm)　and　relatively　high　peel　strength　(0.94　N/mm).　LCM　measurements　indicated　that　optimized　composite　additives　significantly　reduced　surface　roughness,　helping　to　minimize　signal　transmission　losses　and　improve　the　overall　performance　and　reliability　of　PCBs.　In　addition,　the　importance　of　the　three　additives　on　Q　was　in　the　following　order:　sodium　molybdate＞sodium　tungstate＞HEC,　and　the　Q　value　reached　its　maximum　value　(0.76)　under　optimal　conditions.　Through　a　comprehensive　analysis　of　the　additive　mechanism,　the　optimal　composite　additive　formulation　was　identified,　significantly　improving　the　roughening　performance　of　copper　foil.　This　method　not　only　enhanced　peel　strength　and　surface　roughness　but　also　promoted　grain　refinement,　making　the　copper　foil　perform　exceptionally　in　high-performance　electronic　applications.　The　synergistic　effect　of　the　composite　additive　optimized　the　microstructure　of　the　copper　foil,　further　improving　its　overall　mechanical　properties　and　adhesion　characteristics.　The　study　results　demonstrated　that　the　composite　additive　achieved　good　effects　under　different　concentration　conditions,　providing　technical　support　for　producing　low-profile　copper　foil　suitable　for　high-performance　electronic　devices.　By　systematically　optimizing　the　concentrations　of　sodium　molybdate,　sodium　tungstate,　and　HEC　composite　additives,　this　study　significantly　improves　the　surface　and　mechanical　properties　of　ultra-thin　electrolytic　copper　foil,　proposing　innovative　research　findings.　This　research　provides　new　directions　for　the　preparation　of　low-profile　electrolytic　copper　foil,　with　significant　theoretical　and　practical　value.　By　reducing　surface　roughness　while　maintaining　high　peel　strength,　this　study　lays　a　solid　technical　foundation　for　the　miniaturization,　high　performance,　and　long-term　reliability　of　future　electronic　devices,　further　advancing　copper　foil　technology　in　the　electronics　industry.　©　2025　Chongqing　Wujiu　Periodicals　Press.　All　rights　reserved.