I used the following to get a checked background in a latex document (taken from Making a checkered background for a page) :
\documentclass{article}
\usepackage{background}
\usepackage{lipsum}
\newlength\mylen
\setlength\mylen{\dimexpr\paperwidth/150\relax}
\SetBgScale{1}
\SetBgAngle{0}
\SetBgColor{blue!15}
\SetBgContents{\tikz{\draw[step=\mylen]
(-.5\paperwidth,-.5\paperheight) grid
(.5\paperwidth,.5\paperheight);}}
\begin{document}
\lipsum[1-20]
\end{document}
And I got a nice background that I wanted. Now I want the same kind of background in my beamer presentation as well. For that I added the following in the preamble:
\usepackage{background}
\newlength\mylen
\setlength\mylen{\dimexpr\paperwidth/150\relax}
\SetBgScale{1}
\SetBgAngle{0}
\SetBgColor{blue!15}
\SetBgContents{\tikz{\draw[step=\mylen]
(-.5\paperwidth,-.5\paperheight) grid
(.5\paperwidth,.5\paperheight);}}
However, it is is not making any difference to the background, i.e., the same plain background is coming up. How can I have a checkered background on all the slides of my presentation?

