To create CCW is by using InteropServices attributes. Here interfaces are created automatically

Following are different type of class attributes :
None:No class interface is generated for the class. This is default setting when you do not specify anything.

AutoDispatch:Interface that supports IDispatch is created for the class. However, no type information is produced.

AutoDual :A dual interface is created for the class. Type information is produced and made available in the type library.

Below is an example of code that uses third attribute:

Imports System.Runtime.InteropServices _
<ClassInterfaceAttribute(ClassInterfaceType.AutoDual)> _
Public Class ClsCompliant
End Class

Other than class attributes defined up there are other attributes with which you can govern other part of assembly. Example "GuidAttribute" allows you to specify the GUID, "ComVisibleAttribute" can be used to hide .NET types from COM etc.

Once .NET assembly is created using either interface or using interopservices method we need to create a COM type library using Type library export tool. Tlbexp (AssemblyName)

The final thing is registering the CCW in registry using regasm tool. regasm AssemblyName [Options]

Finally refer the TLB in your COM IDE. DLL and TLB should be in same directory where the application is executed