Circuits: VLSI

Puzzle 61 of 100

Metal 2 and vias

Goal

Connect A to Y and B to Z. The two paths must cross without joining; cross them on metal 2.

Die
13 by 9 squares
Layers
Metal, Metal 2, Via
Inputs
B, A
Outputs
Y, Z

Go to the solution

New in this puzzle

Metal 2

Metal 2 is a second layer of metal, on its own level above the first. It conducts as well as metal and passes over every other layer without joining it.

Via

A via is a plug that joins metal 2 to the metal directly under it, as a contact joins metal to the layer below. Placing a via also paints metal and metal 2 in its square.

Guide

  1. Paint metal straight across from A to Y.
  2. Choose Metal 2 and paint the outlined line from below B to above Z, over the A line.
  3. Choose Via and place one at each end of the metal 2 line, beside the pads. Each via joins a pad's metal to the metal 2 line.

Hint

  1. Hint 1 of 3

    Metal 2 lies on a level above metal, so a metal 2 line can pass over a metal line without joining it. A via joins metal 2 to the metal under it. Carry B over the A line on metal 2, with a via at each end.

  2. Hint 2 of 3

    Look near B. The marked square is one possible place to connect Metal to Metal 2.

  3. Hint 3 of 3

    Use Metal 2 for the route between B and Z, with a via at each end. Keep the middle crossing free of vias so A and B remain separate.

These hints describe one valid approach. Other drawings can pass.

Solution

This is the game's reference drawing for the puzzle. It meets the goal and passes the design rules. Other drawings can pass as well.

Top View of the solved die for puzzle 61, Metal 2 and vias, with the Side View below it.
Top View of the solved die, captured from the game. Paths that carry a high level at the moment shown are lit. The Side View below cuts through the row between the dashed lines.
The game window in Isometric View with the solved die for puzzle 61, Metal 2 and vias, the guide, and the scope.
The whole game window in Isometric View. The scope on the right compares each output with its target band, and the message above it confirms that the drawing passes.
Solution drawing for puzzle 61, Metal 2 and vias, drawn on a numbered grid with every layer in its game color and pattern.
The solution on the grid. Squares are numbered from the top left corner, so you can count them.

Legend

  • Metal17 squares
  • Metal 27 squares
  • Via2 squares
  • Input padB, A
  • Output padY, Z

About the drawing

  • The drawing uses 21 of the die's 117 squares.
  • The die starts empty, so you draw every square.
  • 2 vias join metal 2 to the metal under it.

After the puzzle

Both outputs follow their assigned inputs. Separate metal layers can cross without joining; a via makes a connection between them.

Experiment: Via connection

Before records your passing drawing. Remove one via from the route between B and Z, keeping both metal layers. Compare Z before and after the edit. A crossing alone does not connect the layers. Restore Before, then try a different via position while keeping the two signal routes separate.

The experiment is optional. It does not change the puzzle target.