Lithography Techniques/Making a Printed Circuit Board

 

Kerry Paige Teamey

Brooklyn Academy High School

Summer Research Program for Science Teachers

August 2010

 

 

Subject:  Material Science/Physics/Chemistry

Grade Level: 10-12

Unit: Introduction to electricity and electromagnetism (Ceramics/Metal)

Duration:  3 periods (57 minutes each)

Aim:  How are printed circuit boards produced for most electronic equipment?

Objectives:

 

Vocabulary: Insulation, conduction, writing, etching, lithography, soldering, schematic diagrams

 

Materials:

         Radio Shack Copper plates (1 practice plate/1 plate used for FM PCB)

         HCl or related acid for etching

         Found products with known PCB inside (many can be found in streets or second had stores. EXAMPLES:  CD players, mp3, calculator

         Beakers that will fit 2in x 3in PCB

         Camera

         Acetone paper

         Vacuum hood

         Goggles,

         Gloves

         Apon

         Iron

 

Procedure: 

Engage/ Explore (Day 1)

Watch short 2 minute clip on discover.org, how its made.  (Abbreviated version of how printed circuit boards are made can be viewed from this site.)   After clip has been viewed pass around PCB retrieved from found products and have students guess what components they came from.  Students should contrast and compare in groups how pieces are inserted, copper tracks are patterned, and one observation about any electronic component.

Explain (Day 1)

Students will go through a short sample of how negative imaging can be transferred and fixed on PCBs.  Students will use either a picture they have brought from home or a picture in the class room.  (If students have brought a picture they must e-mail it to you or bring it on a flash drive in order to be able to print image on acetone paper.)  Print each picture in black and white option on acetone paper. Iron the transparency onto a copper board
Chemically etch the board using ferric chloride or hydro chloric acid. (MAKE SURE ALL SAFETY EQUIPTMENT IS ON and PROCEDURE IS COMPLETED UNDER HOOD)



Extend (homework assignment)

Students must chose any electronic component that will be used for the FM receiver radio (semiconductor, resistor, TDA receiver, trimmer potentiameter, capacitor) and research how that component is made and what it is used for.  Students must give 3 examples of products that use that specific product besides FM radios)

Engage/Explore (Day 2)

Place all students name on board.  As students are walking into the classroom have each student write down next to their name what electric component they studied the night before.  Group students in groups with unlike products and have each explain how their piece functions examples of products it can be found in.  Students should use graphic sheet to draw and place description of each members electric component that is described.    

Students will be allowed to look at what they etched and wrote on copper plate from day before.  This is usually very exciting because they will be able to keep a negative imprint of their chosen picture and observe what areas kept the copper fixed to the bored and which areas unsheathed the silicon. 

Explore (Days 2 and 3)

Explain to students they will take the exact process that was completed the prior day, but this time create an electronic schematic on their PCB that will look very similar to the samples viewed the previous day.  Students will work in groups of two.  Remind the students of being patient while under the hood and careful with laying the diagram.  Remind students if the diagram is not placed correctly on board their radio will be unable to word.    Using schematic repeat procedures and steps used in day 1 negative imaging. (EXAMPLE BELOW)

Explain (Day 3)

Begin with students reflecting on what they thought about the process of lithography.  Explain to students the next step will be to mark their PCB board and learn how to solder and assemble electronic components.  Students will also learn how to use Dremel to drill or hand drill in appropriate places.

Extend (homework assignment)

Have students make crossword puzzle using ALL electronic circuit vocabulary.  Students will solve each others puzzles the following morning for a quiz.  Students should use graphic organizer used on day 2 from sharing. 

 

New York State Standards: 

Physical Setting/Earth Science Core Curriculum (Regents Earth Science) 

Standard 1: Analysis, Inquiry, and Design-Students will use mathematical analysis, scientific inquiry, and engineering design, as appropriate, to pose questions, seek answers, and develop solutions.

Standard 2: Information Systems Students will access, generate, process, and transfer information, using appropriate technologies

Standard 4:  The Physical Setting/Earth Science (1.2g)

Standard 6: Interconnectedness-Common Themes (Models) Models are simplified representations of objects, structures, or systems used in analysis, explanation, interpretation, or design

Standard 7:  Interdisciplinary Problem Solving

The knowledge and skills of mathematics, science, and technology are used together to make informed decisions and solve problems, especially those relating to issues of science/technology/society, consumer decision making, design, and inquiry into phenomena.

address real-world problems, using scientific methodology