SQL SERVER trigger intersect bug

I have a trigger which check if a points intersects with many polygons, there are 500 points and they are updated every 20 seconds, so we have mote than 1500 updates per minutes, so this trigger causes problem on my server giving an error like this: Exceptions Transaction (Process ID ) was deadlocked on lock resources with another process and has been chosen as the deadlock victim I think this is because trigger is triggered many times, more tan 20 times per second... so what can we do to improve this? PAying only 10 and 15 if you do a bonus, really simple