tikz: Vertically centered aligned node text

Question

I want to align the node text vertically centered. Wondering how to accomplish this?

\documentclass{standalone}
\usepackage[utf8]{inputenc}
\usepackage{fourier, tikz}
\usetikzlibrary{arrows, fit, calc}
\begin{document}
\begin{tikzpicture}[font = \normalsize]
  \begin{scope}[every node/.style={%
  text width     = 3.0cm, 
  text depth     = 2.0cm,
  inner sep      = 2.0mm,
  minimum height = 2.0cm,
  minimum width  = 1.5cm,
  align          = left
  }]
\nodefill = blue!20{\textbf{F}};
\nodefill = red!20, anchor = north west at (T1.north east){\textbf{Co}};
\nodefill = green!20, anchor = north west at (T1.south west){\textbf{Cu}};
\nodefill = yellow!20, anchor = north west at (T1.south east){\textbf{O}}; 
\end{scope}
\begin{scope}[align = center]
 \node [text width = 6cm, above = 0.0ex, anchor = south] (T5) at (T1.north east) {\textbf{I}};
\node [text width = 6cm, below = 0.0ex, anchor = north] (T6) at (T3.south east) {\textbf{U}};
\node text width = 1.5cm, left = 0.0ex, anchor = east at (T1.south west) {\textbf{C}};
\node text width = 0.75cm, right = 0.0ex, anchor = west at (T2.south east) {\textbf{S}};
\end{scope}
\draw[thick] (T5) -- (T6)
             (T7) -- (T8) ;

\end{tikzpicture}
\end{document}

Solution Just removing text width = 3.0cm, text depth = 2.0cm from my working example gives the required solution.

\documentclass{standalone}
\usepackage[utf8]{inputenc}
\usepackage{fourier, tikz}
\usetikzlibrary{arrows, fit, calc}
\begin{document}
\begin{tikzpicture}[font = \normalsize]
  \begin{scope}[every node/.style={%
%  text width     = 3.0cm, 
%  text depth     = 2.0cm,
  inner sep      = 2.0mm,
  minimum height = 2.0cm,
  minimum width  = 1.5cm,
  align          = left
  }]
\nodefill = blue!20{\textbf{F}};
\nodefill = red!20, anchor = north west at (T1.north east){\textbf{Co}};
\nodefill = green!20, anchor = north west at (T1.south west){\textbf{Cu}};
\nodefill = yellow!20, anchor = north west at (T1.south east){\textbf{O}}; 
\end{scope}
\begin{scope}[align = center]
 \node [text width = 6cm, above = 0.0ex, anchor = south] (T5) at (T1.north east) {\textbf{I}};
\node [text width = 6cm, below = 0.0ex, anchor = north] (T6) at (T3.south east) {\textbf{U}};
\node text width = 1.5cm, left = 0.0ex, anchor = east at (T1.south west) {\textbf{C}};
\node text width = 0.75cm, right = 0.0ex, anchor = west at (T2.south east) {\textbf{S}};
\end{scope}
\draw[thick] (T5) -- (T6)
             (T7) -- (T8) ;

\end{tikzpicture}
\end{document}