Simple past or past perfect with "by" and years

What is the difference between

1. 
   

   
   
   

   He became a star by 1990's.

   
   

   
   


2. 
   

   
   

   He had become a star by 1990's.

   
   

   
   

Is the first sentence correct? If yes, then please tell me the difference between the two.