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IPC CID+ Certification Exam (Newest 2025 ) |
Complete Questions and Correct Answers
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What important effect is reduced as an output from copper balancing from the center to either side in the laminated product ---------CORRECT ANSWER------------- ----Bow and Twist What can help straighten a board that does not have proper copper balance from bow and twist? ---------CORRECT ANSWER-----------------Mechanical features like heat sinks and stiffeners What thermal management technique transfers the heat down to a cooler plan/surface? ---------CORRECT ANSWER-----------------Thermal vias Thermal energy/heat that is transferred by electro-magnetic radiation primarily in the infrared (IR) wave length ---------CORRECT ANSWER-----------------Radiation How do large cores/large copper affect the reflow profile? ---------CORRECT ANSWER-----------------Significant heatsink and impact the reflow of the solder surfaces
What is highly advisable to do when a board contains a metal core? --------- CORRECT ANSWER-----------------Add a note on the Assembly Drawing Why does 0402 equate to 0.03936~" x 0.01968~" not 0.04"x0.02"? --------- CORRECT ANSWER-----------------Inaccurate round offs What are the 3 vantage points of dimensioning? ---------CORRECT ANSWER---------- -------Mechanical Constraints Drawing (mating the PCB with the mechanical housing), PCB Master Drawing, QA inspection criteria (ensure conformance of manufactured product for intended usage) For the relationship of the PCB to the Mechanical Constraints drawing, what is critical to do to alleviate problems related to tolerance stackup? ---------CORRECT ANSWER-----------------Using similar origins and coordinates, 0/0 origin (non-plated tooling hole) Unusual shaped boards are placed in an assembly array to do what? --------- CORRECT ANSWER-----------------Maximize material usage and to facilitate board/array handling
When blind and buried vias are prepared after lamination, the drilling step required what? ---------CORRECT ANSWER-----------------Controlled depth Drill goes down only to the layers that are to be connected and does not pierce conductors or violate minimum clearance ---------CORRECT ANSWER----------------- Controlled depth Blind structure (as plated) with a maximum aspect ratio of 1:! terminating on or penetrating a target land with a total length of no more than 0.25mm measured from the structure's capture land foil to the target land ---------CORRECT ANSWER- ----------------Microvia When utilizing a microvia structure, thinner dielectric material will contribute to what? ---------CORRECT ANSWER-----------------Higher reliability What is the most difficult part of the fabrication process? ---------CORRECT ANSWER-----------------Plating down into a via What feature of a PCB is affected b a stackup? ---------CORRECT ANSWER------------- ----Circuit density, balanced construction, pin escape & routability, signal return path & minimizing parasitic cross-talk, lamination, drill, and via plating process, dielectric material properties, and thickness, impedance requirements, overall
board thickness, metal thickness and surface finish, annular ring and drill size & hole producing process What is good practice to add in the manufacturing drilling process? --------- CORRECT ANSWER-----------------Create a separate drill file for each drill layer set In regards to the reliability of a plated through hole, the stress is on what and affects what? ---------CORRECT ANSWER-----------------Stress is on the expansion in the Z-axis, affects the strain in the barrel Ratio of the thickness of a PCB compared to the diameter of the smallest hold drilled in the PCB ---------CORRECT ANSWER-----------------Aspect Ratio What is the fastest dielectric constant and what is it? ---------CORRECT ANSWER---- -------------Air, Dk= High resistance to the flow of direct current and can be polarized by an electrical field ---------CORRECT ANSWER-----------------Dielectric material
CORRECT ANSWER-----------------Energy field is immediate between the trace and plane within the dielectric material What electric properties would a trace see? ---------CORRECT ANSWER----------------
- Capacitance and inductance What does high capacitance between a forward signal and its return path mean? - --------CORRECT ANSWER-----------------Good containment of the electromagnetic field What does low inductance between a forward signal and its return path mean? --- ------CORRECT ANSWER-----------------Good flux cancellation, good containment of the magnetic field What can you do to create a nearly ideal setting for containment of fields associated with power currents? ---------CORRECT ANSWER-----------------Placing power plane between two ground planes OR metal filled with ground or power on all signal layers OR placing assembly inside a solid metal enclosure with gaskets What happens when you route around split planes? ---------CORRECT ANSWER----- ------------Detrimental to signal integrity as they will create parasitic signal noise and energy loss
What can you do to create a localized return path? ---------CORRECT ANSWER------- ----------Add a return path ground via adjacent to the signal via Signals radiate at the edge of the board ---------CORRECT ANSWER----------------- Fringing Concerned with the susceptibility of a circuit from external emissions --------- CORRECT ANSWER-----------------Electro-magnetic compatibility (EMC) Ability to reject unwanted EMI ---------CORRECT ANSWER----------------- Susceptibility What characteristic of conductors can pick up wanted EMI signals, creating an antenna? ---------CORRECT ANSWER-----------------Longer and narrower traces (fatter traces have more capacitance to a nearby ground, lower impedance) What is one way to protect PCBs from stray electromagnetic radiation? --------- CORRECT ANSWER-----------------Proper shielding
What are the benefits of metallic coatings / final(surface) finish? ---------CORRECT ANSWER-----------------Corrosion prevention, Improved long-term solderability Simplest of the wet processes; involves a simple galvanic replacement reaction; the more noble metal in the solution picks up electrons from the less noble metal immersed in the solution and plates out ---------CORRECT ANSWER----------------- Immersion Plating Why would you use immersion plating? ---------CORRECT ANSWER-----------------The thickness is limited to a very thin coating as it is a simple replacement reaction Why is Immersion finishes more beneficial than HASL? ---------CORRECT ANSWER-- ---------------Immersion has a flatter base for attachment What are the assembly challenges/problems with HASL process? ---------CORRECT ANSWER-----------------Coplanarity / solder thickness varies, solder crowning, less uniformity Stencil fits flat on pad, opening is smaller than the land pattern in all dimensions -- -------CORRECT ANSWER-----------------Gasketing
What is the problem with gasketing in HASL? ---------CORRECT ANSWER--------------- --Uneven surfaces cause leakage of paste underneath the stencil What other surface finishes are better/flatter than HASL? ---------CORRECT ANSWER-----------------Gray tin, nickel/gold, nickel/palladium gold, immersion "white" tin, immersion silver, ENIG What surface finish is good for BGAs and surface mount? ---------CORRECT ANSWER-----------------ENIG Why would you use a washable solder mask / what is the advantage? --------- CORRECT ANSWER-----------------Washable masks are removable; they come off in a cleaning operation What is plugging? ---------CORRECT ANSWER-----------------Process to ensure that plated through holes are prevent from being contaminated by the assembly cleaning and plating process chemistries For liquid photo imageable masks, what via process does IPC recommend? --------- CORRECT ANSWER-----------------Plugging
Integral part of the manufacturing and testing process; considered in all aspects during the manufaturing process and NOT confined to an evaluation at the end of the line ---------CORRECT ANSWER-----------------SPC (Statistical Process Control) What is an example of an SPC? ---------CORRECT ANSWER-----------------In-process coupon evaluation may be cross-sectioned and evaluated; first article inspection may be performed to ensure the remainder of the lot would be in conformance These specimens are representative of a the product produced and must represent the process ---------CORRECT ANSWER-----------------Test coupons / specimens What is the purpose of in-process test coupons? ---------CORRECT ANSWER---------- -------Provides a systematic path for continuous improvement, identifies root causes of problems, reduces the number of evaluations that need to be made at the end of the production cycle Hole solderability, thermal stress, plating thickness, layer registration, anything related to hole condition within a 2-sided/multilayer board ---------CORRECT ANSWER-----------------Test coupon AB/R evaluation
Ability of a product to function under given conditions and for a specified period of time without exceeding acceptable failure limits ---------CORRECT ANSWER------- ----------Reliability What is the importance of reliability? ---------CORRECT ANSWER----------------- Determine the functionality of equipment and the environment in which it is to operate Stress testing to failure, focuses on reliability ---------CORRECT ANSWER--------------- --HAST Eliminate infant mortality ---------CORRECT ANSWER-----------------Burn-in Identifies mechanical, physical, visual and electrical test normally required by a customer in order to ensure that the quality life-cycle tracking data is available; specified on applicable performance specification ---------CORRECT ANSWER-------- ---------Product Quality Life-Cycle Tracking Frequency of examination; identify if a production lot meets specific requirements ---------CORRECT ANSWER-----------------Sampling plan
What is the best part for risk to solder cracking due to thermal mismatch? --------- CORRECT ANSWER-----------------Leadless components and castellation-type leads What are key cost drivers for bare board manufacturing? ---------CORRECT ANSWER-----------------Laminate materials/mixed dielectrics, number of layers, total number of holes, minimum hole size, panel utilization, lamination cycles, co- planar, plated via-in-pad epoxy filled, back-drilling, impedance control DRC's for fabricators and assemblers often do not take into account what type of DRCs ---------CORRECT ANSWER-----------------electrical DRC's such as controlled signal lengths for timing Rectangular sheet of base material that is used for the processing of 1+ printed boards, and when required, one or more test coupons ---------CORRECT ANSWER-- ---------------Fabrication Panel Printed board image/patterns plus the additional contiguous deliverable material from the panel (+ tabs, fiducials, tooling holes, etc...) ---------CORRECT ANSWER---- -------------Assembly Array
What is the most common size panel? ---------CORRECT ANSWER----------------- 18x24in, 460x610mm Stencil manufacturer work to what location/ ---------CORRECT ANSWER--------------- --Nominal positioning location between two-dimensional variations What should the designer consider adding to help the stencil manufacturers? ------ ---CORRECT ANSWER-----------------Alignment fiducials What ratio should you never go beyond in terms of the length-to-width ratio? ----- ----CORRECT ANSWER-----------------12:! How do long, thin boards jeopardize conductor routability? ---------CORRECT ANSWER-----------------Routing is primarily on the longitudinal axis and may cause crosstalk and signal integrity problems What is the benefit of copper balancing? ---------CORRECT ANSWER----------------- Uniform exposure to the etching solutions
What is a Thevenin termination? ---------CORRECT ANSWER-----------------Parallel strategy where pair or resistors, whose parallel combination is Zo, is used What is a characteristic of series termination resistors? ---------CORRECT ANSWER- ----------------100% positive reflection at the far end of the trace bc reflection is absorbed by the series termination at the front of the trace and no termination at the far end of the trace Time that a signal takes to travel the length of a conductor ---------CORRECT ANSWER-----------------Propagation Delay What is the difference between a surface microstrip and an embedded microstrip ---------CORRECT ANSWER-----------------Embedded: conductor is referenced to single plan, with outer dielectric material whether it is core material, soldermask, conformal coating Surface: conductor referenced to single plane with dielectric between conductor and plane and AIR Where do you put termination stubs when it is parallel? ---------CORRECT ANSWER-----------------At or beyond the last load What happens when you connect termination before the last load? --------- CORRECT ANSWER-----------------Creates a stub causing a signal reflection
All characteristics that must be considered in the design and manufacture of a PCB for it to perform as an integral part of the circuit ---------CORRECT ANSWER---- -------------Signal Integrity What is a way to minimize propagation delays? ---------CORRECT ANSWER------------ -----Signal paths must be kept short What is the major consideration for critical signal speed? ---------CORRECT ANSWER-----------------Switching of the leading edge (signal rise/fall time, not the clock frequency) [switching speed, not the clock] What happens to potential radiation when an exact impedance match between the source (driver), transmission line conductor, and the load (input IC) exists? ---- -----CORRECT ANSWER-----------------The radiation is minimized What is impedance? ---------CORRECT ANSWER-----------------The property that resists the propagation of energy through the circuit Why are small, fine-line conductors on outer edges a challenge? ---------CORRECT ANSWER-----------------Due to the final copper thickness, it is a challenge to
