Circuits: VLSI is a chip layout puzzle game. Draw the layers of a silicon chip, form connections and transistors, and test the circuit that your drawing creates. Each puzzle asks you to produce a particular set of output signals while meeting the design rules.

Draw the circuit

Paint metal, polysilicon, contacts, active silicon, and wells onto the grid. A transistor forms where polysilicon crosses active silicon. Its dimensions come from the shapes you draw. Later puzzles introduce a second metal layer and vias for connections between layers.

Learn through 100 puzzles

Start with a single metal connection. Work through resistance, transistor switching, logic gates, timing, memory, arithmetic, and small clocked machines across 10 chapters. Guides, concept explanations, hints, and reference drawings help you understand each new idea.

Inspect the result

Watch the simulated input and output signals beside the drawing. Compare each output with its target band, inspect a mismatch, and see how resistance and capacitance affect the result. Design-rule checks point to the affected locations. Top View, Isometric View, Perspective View, and a cross section show how the layers fit together.

Compare and experiment

Keep two named drawings with their measured results and compare their area, transistor count, and output traces. In Sandbox, create an independent circuit, set input signals, add probes and output tests, save projects, and export waveforms.

Features

• 100 puzzles in 10 chapters, from simple connections to memory and small clocked machines.
  
• Draw metal, polysilicon, active silicon, wells, contacts, and vias to form the circuit.
  
• Inspect simulated waveforms, target bands, timing measurements, and design-rule errors.
  
• View the same layout from above, in isometric and perspective views, or through a cross section.
  
• Use puzzle guides, concept explanations, hints, and reference drawings as you learn.
  
• Save and compare two named drawings with their measured results.
  
• Build independent circuits in Sandbox, edit input signals, add probes and output tests, and export waveforms.
  
• Undo and redo edits, save your progress, and choose Dark or Light themes.