diff --git a/mxpic/PDKs/Silterra/directories.yaml b/mxpic/PDKs/Silterra/directories.yaml
new file mode 100644
index 0000000..34dbbf3
--- /dev/null
+++ b/mxpic/PDKs/Silterra/directories.yaml
@@ -0,0 +1,16 @@
+level: 4
+root:
+  - PDKs:
+    - primitives:
+      - directional_couplers
+      - edge_couplers
+      - crossings
+      - multimode_interferometers
+      - photodetectors
+    - composites:
+      - MZIs
+    - electronics:
+      - resistors
+      - capacitors
+    - others:
+      - logos