Place the cake mix, melted butter, 1 egg and cinnamon in large bowl and blend with electric mixer on low speed about 1 minute or until mixture forms ball. With your hands press into ungreased 13x9 inch pan, covering bottom and up sides about 1 inch. Set aside.
Melt chocolate chips in microwave, cool slightly.
Put the melted chocolate, cream cheese and sweetened condensed milk in the same bowl used to mix crust. With the same beaters mix on low 30 seconds. Add the 3 eggs and yogurt. Beat on medium speed for 1 minute.
Pour fillling over crust.
Bake at 325 degrees for 45 to 50 minutes or until center jiggles only slightly.
Remove from oven and cool for 30 minutes. Refrigerate at least 1 hour.