There actually is a way to do this without 3rd party software. See below
I. Create a service
1) Open "Automator" - (Search for it in spotlight if you don't know where it is)
2) Double-Click on the "Service" button to create a new Service.
3) From the "Library" menu on the left hand side, click "Utilities"
4) From the list of Utilities, double-click "Run AppleScript"
5) In the main area, there should be a window that says "Run AppleScript". Above it, choose "No Input" next to "Service receives selected"
6) In the "Run AppleScript" window, replace (* Your script goes here *) with tell application "Finder" to activate
7) Click File --> Save As... and save it as "Finder Activation"
II. Create a Keyboard shortcut for the service
1) Open system preferences
2) Click "Keyboard"
3) Select "Services" from the left hand pane
4) In the right hand pane, Scroll down to the bottom. Under "General", there should be "Finder Activation".
5) Ensure "Finder Activation" is checked
6) Assign a Keyboard shortcut by clicking near the right side of the "Finder Activation" selection. The trick is to assign a shortcut that is not used by any of your favorite applications, since application-level keyboard shortcuts will override this.
Hope this helps.