I want pure white fill so that upper most circle becomes incomplete. But black shade comes in the figure. Is there any easier way to do this?

\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{figure}
\begin{center}
\begin{tikzpicture}[scale=1.0, ,transform shape]
\node [draw, thick, minimum size=1cm, circle] at (0,0) {};
\node [draw, thick, minimum size=1cm, circle] at (1,0) {};
\node [draw, thick, minimum size=1cm, circle] at (2,0) {};
\node [draw, thick, minimum size=1cm, circle] at (-1,0) {};
\node [draw, thick, minimum size=1cm, circle] at (1.5,-0.85) {};
\node [draw, thick, minimum size=1cm, circle] at (0.5,-0.85) {};
\node [draw, thick, minimum size=1cm, circle] at (-0.5,-0.85) {};
\node [draw, thick, minimum size=1cm, circle] at (1.5,0.85) {};
\node [draw, thick, minimum size=1cm, circle] at (0.5,0.85) {};
\node [draw, thick, minimum size=1cm, circle] at (-0.5,0.85) {};
\node [draw, thick, minimum size=1cm, circle] at (1.0,2*0.85) {};
\shade[fill=white!20!white, draw=white!40!black](-1.5,2.0)--(2.5,2.0)--(2.5,2.5)--(-1.5,2.5);
\draw[dotted,thin](-1.5,-2)--(-1.5,2.0)--(2.5,2.0)--(2.5,-2)--(-1.5,-2);
\end{tikzpicture}
\end{center}
\caption{hhhhhhhhh}
\label{figspahre}
\end{figure}
\end{document}
