A　cyanide-free　plating　bath　was　used　for　the　superconformal　deposition　of　silver　into　fine　trenches.　It　shows　that　in　thiosulfate　silver　plating　bath,　cysteine　as　an　additives　adsorbed　on　silver　electrode　surface　could　enhance　the　polarization　of　silver　deposition　and　suppress　silver　deposition　rate.　Trenches　with　300　nm　in　width　were　void-freely　filled　in　this　bath.　©The　Electrochemical　Society.