process_design_rules.tex

\def\micro{\mu m}
\def\um{$\micro$ }
\def\degreesC{$\degree C$ }
\def\percent{$\%$ }
\documentclass[10pt,a4paper,oneside]{article}
\usepackage[left=2cm,right=2cm,top=2cm,bottom=2cm]{geometry}

\input{../global_color_scheme.tex}
\usepackage[utf8]{inputenc}
\usepackage[english]{babel}
\usepackage{forloop}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{gensymb}
\usepackage{mdframed}
\usepackage{graphicx}
\usepackage{tikz}
\usetikzlibrary{arrows,automata,shapes}
\usepackage[siunitx]{circuitikz}
\usepackage{makecell}
\usepackage{array}

\def\WaferClean{\begin{tikzpicture}\node [fill=cyan, rounded corners=5pt] {Clean};\end{tikzpicture}}
\def\WaferSemiClean{\begin{tikzpicture}\node [fill=green, rounded corners=5pt] {Semi clean};\end{tikzpicture}}
\def\WaferNonStandard{\begin{tikzpicture}\node [fill=yellow, rounded corners=5pt] {Non standard};\end{tikzpicture}}

\usepackage[colorlinks=true,linkcolor=blue,urlcolor=black,bookmarksopen=true]{hyperref}
\usepackage{bookmark}
\usepackage{hyperref}
\usepackage{sepfootnotes}
\usepackage{lipsum,tocloft} 
\usetikzlibrary{positioning}
\usetikzlibrary{patterns}

\usepackage{float}
\floatstyle{boxed} 
\restylefloat{figure}

\title{Libre Silicon process design rules}
\date{\today}
\author{
  David Lanzendörfer
  \and
  Hagen Sankowski
}

\makeindex

\newcounter{ct}
\def\CrossSectionOnly{0.3}
\def\CrossAndTopSection{0.2}
\def\CrossAndTopSectionBig{0.3}
\def\VLSILayout{0.4}

\DeclareMathOperator\erfc{erfc}

\setlength{\parindent}{0pt} % get rid of annoying indents

\begin{document}
\begin{abstract}
	\input{../process_abstract.tex}
\end{abstract}
\newpage
\maketitle
\section{Layer Definitions}\label{design_rules_layer_definitions}

\begin{center}
%    \captionof{table}{Mask Layers (for Production)}
    \begin{tabular}{|l|c|c|p{7.5cm}|}
    \hline
        \textbf{Name} & \textbf{GDSII} & \textbf{CIF} & \textbf{Description} \\
    \hline
        PWELL   & 41 & CWP & p-well \\
        NWELL   & 42 & CWN & n-well \\
        ACTIVE  & 43 & CAA & active area \\
        PPLUS   & 44 & CSP & $p^{+}$ implant \\
        NPLUS   & 45 & CSN & $n^{+}$ implant \\
        POLY    & 46 & CPG & poly silicium \\
        CONTACT & 25 & CCC & contact (connects METAL1 to POLY) \\
        METAL1  & 49 & CM1 & lowest metal layer \\
        VIA1    & 50 & CV1 & via layer (connects METAL2 to METAL1) \\
        METAL2  & 51 & CM2 & second metal layer \\
        VIA2    & 61 & CV2 & via layer (connects METAL3 to METAL2) \\
        METAL3  & 62 & CM3 & third metal layer \\
        GLASS   & 52 & COG & passivation / isolation \\
    \hline
    \end{tabular}
\end{center}

\section{General Requirements}\label{design_rules_general_requirements}

\begin{flushleft}
    \begin{tabular}{c p{9cm} c}
        1.1  & All scaled dimensions are specified in Lambda & $\lambda$. \\
        1.2  & All fixed dimensions are specified in Microns & $\mu m$. \\
        1.3  & All geometries must be drawn on grid. The grid size is & $1 \lambda$. \\
        1.4  & Polygones should be rectangles with 90 degree angles only. \\
        1.5  & The die size should be an integer multiple of & $10 \mu m$. \\
    \end{tabular}
\end{flushleft}


\begin{center}
    \begin{tabular}{|l|c|c|}
    \hline
        \textbf{Node} & \textbf{$\lambda$} & \textbf{$2 \lambda$} \\
    \hline
	    1 micron & 500nm & 1$\mu$m \\
	    0.5 micron & 250nm & 500nm \\
	    0.25 micron & 125nm & 250nm \\
    \hline
    \end{tabular}
\end{center}

\section{Process Layer Overview}\label{design_rules_process_layer_overview}

\begin{center}
%    \captionof{table}{Mask Layer Minimum Values}
    \begin{tabular}{|l|c|c|}
    \hline
        \textbf{Name} & \textbf{Minimum Width} & \textbf{Minimum Spacing} \\
    \hline
        PWELL   & 10 $\lambda$ & 10 $\lambda$ \\
        NWELL   & 10 $\lambda$ & 10 $\lambda$ \\
        ACTIVE  & 3  $\lambda$ & 3  $\lambda$ \\
        POLY    & 2  $\lambda$ & 2  $\lambda$ \\
        CONTACT & 2  $\lambda$ & 2  $\lambda$ \\
        METAL1  & 4  $\lambda$ & 4  $\lambda$ \\
        VIA1    & 2  $\lambda$ & 3  $\lambda$ \\
        METAL2  & 4  $\lambda$ & 4  $\lambda$ \\
        VIA2    & 2  $\lambda$ & 3  $\lambda$ \\
        METAL3  & 6  $\lambda$ & 4  $\lambda$ \\
    \hline
    \end{tabular}
\end{center}

\section{Structure Rules}\label{design_rules_structure_rules}

\subsection{PWELL Rules}\label{design_rules_pwell_rules}

\begin{center}
    \begin{tikzpicture}[scale=(.33)]
        \filldraw[fill=pwell] (0, 0) rectangle ++(10, 10) node[near end] {PWELL};
        \draw[<->] (0, 1) -- (10, 1) node[near start, above] {2.2.1};
        \draw[<->] (1, 0) -- (1, 10) node[near start, left] {2.2.1};
        \draw[<->] (10, 5) -- (19, 5) node[near start, above] {2.2.2};
        \filldraw[fill=pwell] (19, 0) rectangle ++(10, 10) node[near end] {PWELL};
        \draw[<->] (29, 5) -- (35, 5) node[near start, above] {2.2.3};
        \filldraw[fill=pwell] (35, 0) rectangle ++(10, 10) node[near end] {PWELL};
    \end{tikzpicture}
\end{center}

\begin{flushleft}
    \begin{tabular}{c l c}
        2.1.1  & Minimum Width of PWELL is & $ 10 \lambda $. \\
        2.1.2  & Minimum Spacing to PWELL at different potential is & $ 10 \lambda $. \\
        2.1.3  & Minimum Spacing to PWELL at same potential is & $ 0 \lambda $. \\
        2.1.4  & Minimum Spacing to NWELL is & $ 12 \lambda $. \\
    \end{tabular}
\end{flushleft}

\subsection{NWELL Rules}\label{design_rules_nwell_rules}

\begin{center}
    \begin{tikzpicture}[scale=(.33)]
        \filldraw[fill=nwell] (0, 0) rectangle ++(10, 10) node[near end] {NWELL};
        \draw[<->] (0, 1) -- (10, 1) node[near start, above] {2.2.1};
        \draw[<->] (1, 0) -- (1, 10) node[near start, left] {2.2.1};
        \draw[<->] (10, 5) -- (19, 5) node[near start, above] {2.2.2};
        \filldraw[fill=nwell] (19, 0) rectangle ++(10, 10) node[near end] {NWELL};
        \draw[<->] (29, 5) -- (35, 5) node[near start, above] {2.2.3};
        \filldraw[fill=nwell] (35, 0) rectangle ++(10, 10) node[near end] {NWELL};
    \end{tikzpicture}
\end{center}

\begin{flushleft}
    \begin{tabular}{c l c}
        2.2.1  & Minimum Width of NWELL is & $ 10 \lambda $. \\
        2.2.2  & Minimum Spacing to NWELL at different potential is & $ 10 \lambda $. \\
        2.2.3  & Minimum Spacing to NWELL at same potential is & $ 0 \lambda $. \\
        2.2.4  & Minimum Spacing to PWELL is & $ 12 \lambda $. \\
    \end{tabular}
\end{flushleft}

\subsection{PBASE Rules}\label{design_rules_pbase_rules}

\begin{center}
    \begin{tikzpicture}[scale=(.33)]
        \filldraw[fill=nwell] (0, 0) rectangle (10, 10);
        \filldraw[fill=pbase] (1, 1) rectangle ( 9,  9);
	\node at (5,0.5) {NWELL};
	\node at (5,1.5) {PBASE};
	% overlap
        \draw[<->] (0, 1) -- ( 1,  1) node[near start, above] {2.2.6};
        \draw[<->] (9, 9) -- (10,  9) node[near start, above] {2.2.6};
        \draw[<->] (1, 9) -- ( 1, 10) node[near start, left] {2.2.6};
        \draw[<->] (9, 0) -- ( 9,  1) node[near start, right] {2.2.6};
	% width
        \draw[<->] (1, 5) -- ( 9,  5) node[near start, above] {2.2.5};
    \end{tikzpicture}
\end{center}

\begin{flushleft}
    \begin{tabular}{c l c}
        2.2.5  & Minimum Width of PBASE is & $ 10 \lambda $. \\
        2.2.6  & Minimum Overlap of PBASE to NWELL is & $ 5 \lambda $. \\
    \end{tabular}
\end{flushleft}

\subsection{NBASE Rules}\label{design_rules_nbase_rules}

\begin{center}
    \begin{tikzpicture}[scale=(.33)]
        \filldraw[fill=nwell] (0, 0) rectangle (10, 10);
        \filldraw[fill=pbase] (1, 1) rectangle ( 9,  9);
        \filldraw[fill=nbase] (2, 2) rectangle ( 8,  8);
	\node at (5,0.5) {NWELL};
	\node at (5,1.5) {PBASE};
	\node at (5,2.5) {NBASE};
	% overlap
        \draw[<->] (1, 2) -- ( 2,  2) node[near start, above] {2.2.8};
        \draw[<->] (8, 8) -- ( 9,  8) node[near start, above] {2.2.8};
        \draw[<->] (2, 8) -- ( 2,  9) node[near start, left] {2.2.8};
        \draw[<->] (8, 1) -- ( 8,  2) node[near start, right] {2.2.8};
	% width
        \draw[<->] (2, 5) -- ( 8,  5) node[near start, above] {2.2.7};
    \end{tikzpicture}
\end{center}

\begin{flushleft}
    \begin{tabular}{c l c}
        2.2.7  & Minimum Width of NBASE is & $ 10 \lambda $. \\
        2.2.8  & Minimum Overlap of NBASE to PBASE is & $ 5 \lambda $. \\
    \end{tabular}
\end{flushleft}


\subsection{ACTIVE Rules}\label{design_rules_active_rules}

\begin{center}
    \begin{tikzpicture}[scale=(.33)]
        \filldraw[fill=pwell] (0, 0) rectangle (10, 10);
        \filldraw[fill=nwell] (20, 0) rectangle (30, 10);

        \filldraw[fill=gray] (2,2) rectangle (4,5);
        \filldraw[fill=gray] (6,2) rectangle (8,8);
        \filldraw[fill=gray] (22,2) rectangle (24,8);
        \filldraw[fill=gray] (26,2) rectangle (28,5);

        \node at(2,10.5) {PWELL};
        \node at(22,10.5) {NWELL};
        \node at(7,8.5) {ACTIVE};
 	\draw[<->] (0, 4) -- ( 2, 4) node[near start, below] {2.3.3};
	\draw[<->] (4, 4) -- ( 6, 4) node[near start, below] {2.3.2};
	\draw[<->] (8, 4) -- (10, 4) node[near start, below] {2.3.3};

 	\draw[<->] (2, 0) -- ( 2, 2) node[near start, below] {2.3.3};
  	\draw[<->] (6, 0) -- ( 6, 2) node[near start, below] {2.3.3};
	
	\draw[<->] (22, 3) -- (24, 3) node[near start, below] {2.3.1};
	\draw[<->] (27, 2) -- (27, 5) node[near start, below] {2.3.1};
    \end{tikzpicture}
\end{center}

\begin{flushleft}
    \begin{tabular}{c l c}
        2.3.1   & Minimum Width/Height of ACTIVE is & $3 \lambda$. \\
        2.3.2   & Minimum Spacing to ACTIVE is & $3 \lambda$. \\
        2.3.3   & Minimum ACTIVE surround by PWELL/NWELL/PBASE/NBASE is & $6 \lambda$. \\
    \end{tabular}
\end{flushleft}

\subsection{POLY Rules}\label{design_rules_poly_rules}

\begin{center}
    \begin{tikzpicture}[scale=(.4)]
        \filldraw[fill=nwell] (-1.5, -1.5) rectangle (15.5, 13.5);
        \filldraw[fill=poly,opacity=0.5] (0, 0) rectangle ++(2, 12);
        \draw[<->] (0, 6) -- (2, 6) node[near start, above] {2.4.1};
        \draw[<->] (2, 4) -- (4, 4) node[near start, above] {2.4.3};
        \filldraw[fill=gray] (7, 0) rectangle ++(5, 12);
        \draw[<->] (10, 5) -- (10, 7) node[near start, left] {2.4.2};
        \draw[<->] (9, 0) -- (9, 3) node[near start, right] {2.4.5};
        \filldraw[fill=poly,opacity=0.5] (4, 5) -- ++(10, 0) -- ++(0, -2) -- ++(-8, 0) -- ++(0, -3) -- ++(-2, 0) -- ++(0, 5);
        \filldraw[fill=poly,opacity=0.5] (4, 7) -- ++(0, 5) -- ++(2, 0) -- ++(0, -3) -- ++(8, 0) -- ++(0, -2) -- ++(-10, 0);
        \draw[<->] (12, 8) -- (14, 8) node[near start, above] {2.4.4};
        \draw[<->] (6, 12) -- (7, 12) node[near start, above] {2.4.6};
        \draw[<->] (14, 7.0) -- (15.5, 7.0) node[near start, below] {2.4.7};
        \draw[<->] (-1.5, 8.0) -- (0, 8.0) node[near start, above] {2.4.7};
	\node at(1,12.5) {POLY};
	\node at(10,12.5) {ACTIVE};
	\node at(0,-1) {WELL};
    \end{tikzpicture}
\end{center}

\begin{flushleft}
    \begin{tabular}{c l c}
        2.4.1   & Minimum Width of POLY is & $2 \lambda$. \\
        2.4.2   & Minimum Spacing to POLY over ACTIVE is & $2 \lambda$. \\
        2.4.3   & Minimum Spacing to POLY over others is & $2 \lambda$. \\
        2.4.4   & Minimum Gate extension beyond ACTIVE is & $2 \lambda$. \\
        2.4.5   & Minimum ACTIVE extension beyond POLY is & $3 \lambda$. \\
        2.4.6   & Minimum Spacing of POLY to ACTIVE is & $1 \lambda$. \\
        2.4.7   & Minimum POLY surround by PWELL/NWELL/PBASE/NBASE is & $1 \lambda$. \\
    \end{tabular}
\end{flushleft}

\newpage

\subsection{NPLUS/PPLUS (nimplant/pimplant) Rules}\label{design_rules_plus_rules}

\begin{center}
    \begin{tikzpicture}[scale=(.5)]
        \filldraw[fill=pwell] (0, 0) rectangle (12, 10);
        \filldraw[fill=nwell] (18, 0) rectangle (30, 10);

        \filldraw[fill=gray, opacity=0.5] (2,2) rectangle (4,5);
        \filldraw[fill=gray, opacity=0.5] (6,2) rectangle (8,8);
        \filldraw[fill=gray, opacity=0.5] (22,2) rectangle (24,8);
        \filldraw[fill=gray, opacity=0.5] (26,2) rectangle (28,5);
        
         \filldraw[fill=poly] (5,4) rectangle (11,6);
         \filldraw[fill=poly] (19,4) rectangle (25,6);

        \filldraw[fill=red, opacity=0.5] (1.75,1.75) rectangle (4.25,5.25);
        \filldraw[fill=blue, opacity=0.5] (5.75,1.75) rectangle (8.25,8.25);
        \filldraw[fill=red, opacity=0.5] (21.75,1.75) rectangle (24.25,8.25);
        \filldraw[fill=blue, opacity=0.5] (25.75,1.75) rectangle (28.25,5.25);

        \node at(2,10.5) {PWELL};
        \node at(20,10.5) {NWELL};

        \node at(7,8.75) {NPLUS};
        \node at(23,8.75) {PPLUS};

        \draw[<->] (4.25,2) -- (5.75,2) node[near start, below] {2.5.3};
        \draw[<->] (8.25,2) -- (21.75,2) node[near start, above] {2.5.3};
        \draw[<->] (8.25,6) -- (8.25,8.25) node[near start, right] {2.5.1}; 
        \draw[<->] (24,2) -- (24.25,2) node[near start, below] {2.5.2};
    \end{tikzpicture}
\end{center}

\begin{flushleft}
    \begin{tabular}{c l c}
        2.5.1   & Minimum Spacing to POLY is & $3 \lambda$. \\
        2.5.2   & Minimum Overlap to ACTIVE is & $2 \lambda$. \\
        2.5.3   & Minimum Spacing to NPLUS/PPLUS of opposite type is & $4 \lambda$. \\
    \end{tabular}
\end{flushleft}

\subsection{CONTACT Rules}\label{design_rules_contact_rules}

\begin{center}
    \begin{tikzpicture}[scale=(.6)]
        \filldraw[fill=nwell] (0, 0) rectangle (12, 10);
        \filldraw[fill=gray, opacity=0.5] (2,2) rectangle (4,5);
        \filldraw[fill=gray, opacity=0.5] (6,2) rectangle (8,8);
        \filldraw[fill=poly] (5,4) rectangle (11,6);
        \filldraw[fill=blue, opacity=0.5] (1.75,1.75) rectangle (4.25,5.25);
        \filldraw[fill=red, opacity=0.5] (5.75,1.75) rectangle (8.25,8.25);
        \filldraw[fill=gray] (2.5, 3) rectangle ++(1, 1);
        \filldraw[fill=gray] (6.5, 2.5) rectangle ++(1, 1);
        \filldraw[fill=gray] (6.5, 6.5) rectangle ++(1, 1);
        \filldraw[fill=gray] (9.5, 4.5) rectangle ++(1, 1);

        \filldraw[fill=poly, opacity=0.5] (14,2) rectangle (16,6);
        \filldraw[fill=gray] (14.5, 4.5) rectangle ++(1, 1);
        
        \draw[<->] (2,4) -- (2.5,4) node[near start, above] {2.6.2};
        
        \draw[<->] (2.5,3) -- (3.5,3) node[near start, below] {2.6.1};
        \draw[<->] (3.5,3) -- (3.5,4) node[near start, right] {2.6.1};
        
         \draw[<->] (3.5,3.5) -- (6.5,3.5) node[near end, below] {2.6.3};
         \draw[<->] (6.5,3.5) -- (6.5,6.5) node[near end, left] {2.6.3};
         
         \draw[<->] (7.5,6.0) -- (7.5,6.5) node[near end, right] {2.6.4};

          \draw (7.5,1) -- (7.5,2.5);
          \draw (9.5,1) -- (9.5,4.5);
          \draw[<->] (7.5,1) --  (9.5,1) node[near end, below] {2.6.6};

          \draw[<->] (10.5, 4.5) -- (14.5, 4.5) node[near end, below] {2.6.5};
    \end{tikzpicture}
\end{center}

\begin{flushleft}
    \begin{tabular}{c l c}
        2.6.1   & Exact Width/Height of CONTACT is & $ 2 \lambda \times 2 \lambda$. \\
        2.6.2   & Minimum Overlap by POLY or ACTIVE is & $1 \lambda$. \\
        2.6.3   & Minimum Spacing to CONTACT is & $2 \lambda$. \\
        2.6.4   & Minimum Spacing to Gate is & $2 \lambda$. \\
        2.6.5   & Minimum Spacing of POLY CONTACT to other POLY is & $4 \lambda$. \\
        2.6.6   & Minimum Spacing of ACTIVE CONTACT to POLY CONTACT is & $4 \lambda$. \\
    \end{tabular}
\end{flushleft}

\subsection{METAL1 Rules}\label{design_rules_metal1_rules}

\begin{center}
    \begin{tikzpicture}[scale=(.33)]
        \filldraw[fill=metal1] (0, 0) rectangle ++(4, 10);
        \draw[<->] (0, 1) -- (4, 1) node[near start, above] {2.7.1};
        \draw[<->] (4, 5) -- (8, 5) node[near start, above] {2.7.2};
        \filldraw[fill=metal1] (8, 0) rectangle ++(4, 10);
        \filldraw[fill=titanium] (9, 1) rectangle ++(2, 2); % !! color code
        \draw[<->] (8, 2) -- (9, 2) node[near start, above] {2.7.3};
        \draw[<->] (12, 5) -- (18, 5) node[near start, above] {2.7.4};
        \filldraw[fill=metal1] (18, 0) rectangle ++(20, 10);
        \draw[<->] (18, 1) -- (38, 1) node[near start, above] {$ \geq 10 \mu m$};
        \node at (2.0,11) {METAL1};
        \node at (21.5,11) {(Big-)METAL1};
    \end{tikzpicture}
\end{center}

\begin{flushleft}
    \begin{tabular}{c l c}
        2.7.1   & Minimum Width of METAL1 is & $4 \lambda$. \\
        2.7.2   & Minimum Spacing of METAL1 is & $4 \lambda$. \\
        2.7.3   & Minimum Overlap of CONTACT or VIA is & $1 \lambda$. \\
        2.7.4   & Minimum Spacing to METAL1 for lines wider than $10 \mu m$ is & $6 \lambda$. \\
    \end{tabular}
\end{flushleft}

\subsection{VIA1 Rules}\label{design_rules_via1_rules}

\begin{flushleft}
    \begin{tabular}{c l c}
        2.8.1   & Exact Width/Height of VIA1 is & $ 2 \lambda \times 2 \lambda$. \\
        2.8.2   & Minimum Spacing to VIA1 is & $3 \lambda$. \\
        2.8.3   & Minimum Spacing to CONTACT is & $2 \lambda$. \\
        2.8.4   & Minimum Spacing to POLY or ACTIVE is & $2 \lambda$. \\
    \end{tabular}
\end{flushleft}

\subsection{METAL2 Rules}\label{design_rules_metal2_rules}

\begin{center}
    \begin{tikzpicture}[scale=(.33)]
        \filldraw[fill=metal2] (0, 0) rectangle ++(4, 10) node[near end] {METAL2};
        \draw[<->] (0, 1) -- (4, 1) node[near start, above] {2.9.1};
        \draw[<->] (4, 5) -- (8, 5) node[near start, above] {2.9.2};
        \filldraw[fill=metal2] (8, 0) rectangle ++(4, 10) node[near end] {METAL2};
        \filldraw[fill=via1] (9, 1) rectangle ++(2, 2); % !! color code
        \draw[<->] (8, 2) -- (9, 2) node[near start, above] {2.9.3};
        \draw[<->] (12, 5) -- (18, 5) node[near start, above] {2.9.4};
        \filldraw[fill=metal2] (18, 0) rectangle ++(20, 10) node[near end] {(Big-)METAL2};
        \draw[<->] (18, 1) -- (38, 1) node[near start, above] {$ \geq 10 \mu m$};
    \end{tikzpicture}
\end{center}

\begin{flushleft}
    \begin{tabular}{c l c}
        2.9.1   & Minimum Width of METAL2 is & $4 \lambda$. \\
        2.9.2   & Minimum Spacing to METAL2 is & $4 \lambda$. \\
        2.9.3   & Minimum Overlap to VIA1 is & $1 \lambda$. \\
        2.9.4   & Minimum Spacing to METAL2 for lines wider than $10 \mu m$ is & $6 \lambda$. \\
    \end{tabular}
\end{flushleft}

\subsection{VIA2 Rules}\label{design_rules_via2_rules}

\begin{flushleft}
    \begin{tabular}{c l c}
	2.10.1   & Exact Width/Height of VIA2 is & $ 2 \lambda \times 2 \lambda$. \\
        2.10.2   & Minimum Spacing to VIA2 is & $3 \lambda$. \\
    \end{tabular}
\end{flushleft}

\subsection{METAL3 Rules}\label{design_rules_metal3_rules}

\begin{center}
    \begin{tikzpicture}[scale=(.33)]
        \filldraw[fill=metal2] (0, 0) rectangle ++(4, 10) node[near end] {METAL3}; % !! color code
        \draw[<->] (0, 1) -- (4, 1) node[near start, above] {2.11.1};
        \draw[<->] (4, 5) -- (8, 5) node[near start, above] {2.11.2};
        \filldraw[fill=metal2] (8, 0) rectangle ++(4, 10) node[near end] {METAL3}; % !! color code
        \filldraw[fill=via2] (9, 1) rectangle ++(2, 2); % !! color code
        \draw[<->] (8, 2) -- (9, 2) node[near start, above] {2.11.3};
        \draw[<->] (12, 5) -- (18, 5) node[near start, above] {2.11.4};
        \filldraw[fill=metal2] (18, 0) rectangle ++(20, 10) node[near end] {(Big-)METAL3}; % !! color code
        \draw[<->] (18, 1) -- (38, 1) node[near start, above] {$ \geq 10 \mu m$};
    \end{tikzpicture}
\end{center}

\begin{flushleft}
    \begin{tabular}{c l c}
        4.11.1  & Minimum Width of METAL3 is & $6 \lambda$. \\
        2.11.2  & Minimum Spacing to METAL3 is & $4 \lambda$. \\
        2.11.3  & Minimum Overlap to VIA2 is & $1 \lambda$. \\
        2.11.4  & Minimum Spacing to METAL3 for lines wider than $10 \mu m$ is & $6 \lambda$. \\
    \end{tabular}
\end{flushleft}

\subsection{GLASS Rules}\label{design_rules_glass_rules}

\begin{flushleft}
    \begin{tabular}{c l c}
	2.12.1  & Exact Width/Height of GLASS is & $ 120 \lambda \times 120 \lambda$. \\
        2.12.2  & Minimum METAL3 Overlap of GLASS opening is & $ 12 \lambda $. \\
        2.12.3  & Minimum Spacing of pad METAL3 to unrelated METAL is & $30 \mu m$. \\
        2.12.4  & Minimum Spacing of pad METAL3 to ACTIVE or POLY is & $15 \mu m$. \\
    \end{tabular}
\end{flushleft}

\end{document}