Layer stack configuration in PCB Design - Real Business Scenario

Scenario Mode

👤 Your Role: You are a PCB design engineer working on a new multilayer circuit board.

📋 Request: Your manager wants a clear report showing the layer stack configuration details to ensure signal integrity and manufacturing feasibility.

📊 Data: You have data about each layer's type (signal, power, ground), thickness in micrometers, and material type for a 6-layer PCB.

🎯 Deliverable: Create a dashboard report that lists each layer with its type, thickness, and material, and visualize the total thickness and layer distribution.

Sample Data

Layer Number	Layer Name	Layer Type	Thickness (µm)	Material
1	Top Signal	Signal	35	Copper
2	Prepreg 1	Dielectric	100	FR4
3	Inner Ground	Ground	35	Copper
4	Inner Power	Power	35	Copper
5	Prepreg 2	Dielectric	100	FR4
6	Bottom Signal	Signal	35	Copper

1

Step 1: Create a table visualization listing all layers with columns: Layer Number, Layer Name, Layer Type, Thickness (µm), Material.

Use the sample data as is to create a table in your BI tool with the specified columns.

Expected Result

A clear table showing all 6 layers with their details.

2

Step 2: Calculate the total thickness of the PCB by summing the Thickness (µm) column.

Total Thickness = SUM('Layer Stack'[Thickness (µm)])

Expected Result

Total Thickness = 35 + 100 + 35 + 35 + 100 + 35 = 340 µm

3

Step 3: Create a bar chart showing the thickness of each layer by Layer Name.

X-axis: Layer Name; Y-axis: Thickness (µm); Bar color by Layer Type.

Expected Result

A bar chart with 6 bars, each representing a layer's thickness, colored by type (Signal, Power, Ground, Dielectric).

4

Step 4: Create a pie chart showing the proportion of total thickness by Layer Type.

Group data by Layer Type and sum Thickness (µm) for each group.

Expected Result

Pie chart showing thickness distribution: Signal (105 µm), Dielectric (200 µm), Ground (35 µm), Power (35 µm).

5

Step 5: Add a card visualization showing the total number of layers.

Number of Layers = COUNTROWS('Layer Stack')

Expected Result

Card showing '6' as total layers.

Final Result

Bar Chart: Layer Thickness by Layer Name, colored by Layer Type

↓

Pie Chart: Thickness Distribution by Layer Type

↓

Card: Total Layers = 6

✓The PCB has 6 layers with a total thickness of 340 micrometers.

✓Dielectric layers (Prepreg 1 and 2) contribute the most thickness (200 µm).

✓Signal layers are on the top and bottom, each 35 µm thick, totaling 105 µm.

✓Ground and Power layers are each 35 µm thick, providing stable reference planes.

Bonus Challenge

Add a calculation to find the percentage thickness contribution of each layer type and visualize it in a stacked bar chart.

Show Hint

Calculate percentage by dividing each Layer Type's total thickness by the overall total thickness, then multiply by 100.

Practice

1. What is the main purpose of a layer stack configuration in PCB design?

easy

A. To organize the different layers for signal quality and manufacturability

B. To write software code for the PCB

C. To select the color of the PCB

D. To decide the shape of the PCB

Solution

1. Step 1: Understand layer stack role

   The layer stack configuration arranges copper and dielectric layers to ensure proper electrical performance and manufacturability.

2. Step 2: Eliminate unrelated options

   Writing code, choosing color, or shape are unrelated to layer stack configuration.

3. Final Answer:

   To organize the different layers for signal quality and manufacturability -> Option A

4. Quick Check:

   Layer stack = organize layers for function [OK]

Hint: Layer stack = organizing PCB layers for function [OK]

Common Mistakes:

• Confusing layer stack with PCB shape or color
• Thinking layer stack is about software code
• Ignoring the role of layers in signal quality

2. Which of the following is the correct way to describe a layer stack configuration?

easy

A. A list of software functions for PCB control

B. A sequence of copper and dielectric layers with thickness and material specified

C. A set of colors used on the PCB surface

D. A list of drill hole sizes only

Solution

1. Step 1: Identify layer stack components

   Layer stack includes copper and dielectric layers with defined thickness and materials.

2. Step 2: Remove unrelated descriptions

   Software functions, colors, or drill hole sizes alone do not define layer stack configuration.

3. Final Answer:

   A sequence of copper and dielectric layers with thickness and material specified -> Option B

4. Quick Check:

   Layer stack = copper + dielectric layers [OK]

Hint: Layer stack = copper + dielectric layers with thickness [OK]

Common Mistakes:

• Confusing layer stack with software or color settings
• Ignoring thickness and material details
• Thinking drill holes define layer stack

3. Given a layer stack with 4 copper layers and 3 dielectric layers, what is the total number of layers in the stack?

medium

A. 7 layers total

B. 3 layers total

C. 4 layers total

D. 12 layers total

Solution

1. Step 1: Count copper layers

   There are 4 copper layers.

2. Step 2: Count dielectric layers and sum

   There are 3 dielectric layers. Total layers = 4 + 3 = 7.

3. Final Answer:

   7 layers total -> Option A

4. Quick Check:

   4 copper + 3 dielectric = 7 layers [OK]

Hint: Add copper and dielectric layers for total [OK]

Common Mistakes:

• Counting only copper or only dielectric layers
• Multiplying instead of adding layers
• Confusing layers with thickness values

4. A PCB designer wrote this layer stack configuration but the PCB is too thick. Which part is likely causing the issue?

LayerStack = [
  {"type": "copper", "thickness": 0.035},
  {"type": "dielectric", "thickness": 0.5},
  {"type": "copper", "thickness": 0.035},
  {"type": "dielectric", "thickness": 1.5}
]

medium

A. The layer types are incorrect

B. Copper layers are too thick

C. There are too many copper layers

D. Dielectric layer with thickness 1.5 is too thick

Solution

1. Step 1: Review thickness values

   Copper layers have thickness 0.035, which is typical. Dielectric layers have 0.5 and 1.5 thickness.

2. Step 2: Identify unusually thick layer

   Dielectric layer with 1.5 thickness is unusually thick and likely causes overall PCB thickness issue.

3. Final Answer:

   Dielectric layer with thickness 1.5 is too thick -> Option D

4. Quick Check:

   Thick dielectric layer = thickness issue [OK]

Hint: Check dielectric thickness for PCB thickness issues [OK]

Common Mistakes:

• Blaming copper thickness without checking values
• Ignoring dielectric thickness impact
• Assuming layer types are wrong without evidence

5. You need to design a 6-layer PCB with controlled impedance and minimal thickness. Which layer stack configuration approach is best?

hard

A. Use only copper layers without dielectric layers

B. Use thick dielectric layers between all copper layers to reduce cost

C. Alternate thin dielectric and copper layers with precise thickness control

D. Stack all copper layers together and place dielectric layers on top

Solution

1. Step 1: Understand design goals

   Controlled impedance and minimal thickness require precise layer thickness and alternating copper and dielectric layers.

2. Step 2: Evaluate options

   Thick dielectric increases thickness and reduces control. Copper-only or stacking copper layers together ignores dielectric role.

3. Final Answer:

   Alternate thin dielectric and copper layers with precise thickness control -> Option C

4. Quick Check:

   Thin dielectric + copper layers = controlled impedance [OK]

Hint: Alternate thin dielectric and copper for control and thinness [OK]

Common Mistakes:

• Using thick dielectric layers increasing thickness
• Ignoring dielectric layers for impedance control
• Stacking copper layers without dielectric separation