IPC Design Standard: IPC-2221, IPC-2222, IPC-2223, IPC-2224, IPC-2225, IPC-2226 & IPC-2227

IPC-2221 standard is intended to provide information on the generic requirement for organic printed board design. All aspects and details of the design requirements are addressed to the extent that can be applied to the broad spectrum of those designs that use organic materials or organic materials in combination with inorganic materials (metal, glass, ceramic, etc.) to provide the structure for mounting and interconnecting electronic, electromechanical, and mechanical components. It is crucial that a decision pertaining to the choice of product types be made as early as possible. Once a component mounting and interconnection technology has been selected the user should obtain the sectional documents, like IPC-2222, IPC 2223, IPC-2224, IPC-2225, IPC-2226 and IPC-2227, that provides the specific focus on the chosen technology.

IPC-2221 is the foundation design standard for all IPC-2220 design series. It established the generic requirements for the design of printed boards and other forms of component mounting or interconnecting structures, whether single-sided, double-sided or multi-layered. This standard also provides test coupon design used for lot acceptance and quality conformance testing.

IPC-2221 Documentation Hierarchy

  • IPC-2221 standard identifies the generic physical design principles, and is supplemented by various sectional documents that provide details and shapers focus on specific aspects of printed board technology. This list is a particular summary and is not inherently a part of this generic standard. The documents are a part of the PCB Design Document Set which is identified as IPC-2220.

  • IPC-2222: Sectional Design Standard for Rigid Organic Printed Boards

  • IPC-2223: Sectional Design Standard for Flexible Printed Boards

  • IPC-2224: Sectional Standard for Design of PWBs for PC Cards

  • IPC-2225: Sectional Design Standard for Organic Multichip Modules (MCM-L) and MCM-L Assemblies

  • IPC-2226: Sectional Design Standard for High Density Interconnect (HDI) Printed Boards

  • IPC-2227: Sectional Design Standard for Embedded Passive Printed Board Embedded Passives

*At present, we don’t talk about IPC-2227 standard.

IPC-2222: Sectional Design Standard for Rigid Organic Printed Boards

Used in conjunction with IPC-2221, IPC-2222 establishes the specific requirements for the design of rigid organic printed boards and other forms of component mounting and interconnecting structures. This standard applies to single-sided, double-sided or multi-layered PCB boards. The key concepts of IPC-2222 are listed below:

  • Rigid Laminate Properties

  • Printed Board Assembly

  • Holes/Interconnections

  • Dielectric Spacing

  • Lead-free Laminate Materials

  • Scoring and Routing Parameters

  • Printed Board Thickness Parameters

  • Printed Board Thickness Tolerance

  • Nonfunctional Lands

  • Hole Aspect Ratios

  • Clearance Areas in Planes

IPC-2223: Sectional Design Standard for Flexible Printed Boards

Used in conjunction with IPC-2221, IPC-2223 establishes the specific requirements for the design of Flexible Printed Boards and forms of component mounting and interconnecting structures. The flexible materials used in the structures are comprised of insulating films, reinforced and/or non-reinforced dielectric in combination with metallic materials. The key concepts of IPC-2223 are listed below,

  • Material Selection and Construction

  • Selective (Button) Plating

  • Minimum Bending for Flexible Circuits with Coverlay

  • Impedance and Capacitance Control

  • Unsupported Edge Conductors/Fingers

  • Copper Filled Vias/Microvias

IPC-2224: Sectional Standard for Design of PWBs for PC Cards

IPC-2224 standard establishes the requirements for the design of printed wiring boards for PC Card form factors. The organic materials may be homogeneous, reinforced, or used in combination with inorganic materials. The interconnections may be single-sided, double-sided, or multi-layered. The requirements contained are intended to establish design principles and recommendations that shall be used in conjunction with IPC-2221 to produce detailed designs intended to mount and attach passive and active components, which may be through-hole, surface mounting, fine pitch, ultra-fine pitch, array mounting or unpackaged bare die. The materials may be any combination able to perform the physical, thermal, environmental, and electronic functions. The PCB board types are listed below,

  • Type 1: Single-sided Printed Board

  • Type 2: Double-sided Printed Board

  • Type 3: Multilayer Board without Blind or Buried Vias

  • Type 4: Multilayer Board with Blind or Buried Vias

  • Type 5: Multilayer Metal Core Board without Blind or Buried Vias

  • Type 6: Multilayer Metal Core Board with Blind or Buried Vias

IPC-2225: Sectional Design Standard for Organic Multichip Modules (MCM-L) and MCM-L Assemblies

IPC-2225 standard establishes requirements and other considerations (thermal, electrical, electromechanical and mechanical) for the design of organic mounting structure used to interconnect chip components, which in combination form the completed functional Single Chip Module (SCM-L), MCM, or MCM-L assemblies. Key concepts include adhesive interconnection information, typical die attach materials, microvia material properties.

IPC-2226: Sectional Design Standard for High Density Interconnect (HDI) Printed Boards

IPC-2226 standard establishes requirements and considerations for the design of organic and inorganic high-density interconnect (HDI) printed boards and structures for components mounting and interconnections. The requirements contained herein are intended to establish design principles and recommendations that shall be used in conjunction with the detailed requirements of IPC-2221. In addition, when the core material reflects requirements identified in the sectional standards (IPC-222, IPC-2223 and IPC-2225), that information becomes a mandatory part of this standard. IPC-2226 provides recommendations for signal, power, ground, and mixed distribution layers, dielectric separation, via formation and metallization requirements and other design features that are necessary for HDI substrates.

When fine pitch BGA <0.65mm or 0.5mm, HDI design must be used. Generally, BGA routing requires one or all of following: micro traces, VIP (Via In Pad), microvias, blind vias or other microvia technique, built-up laminations and high-speed performance considerations. For microvia formation, the prepreg materials should be thin down to 2mil (0.05mm).

IPC-2226 HDI Types

The design designation system of IPC-2226 standard recognizes the six industry approved design types used in the manufacture of HDI printed boards. The designations in this section determine the HDI design type by defining the number and location of HDI layers that may or may not be combined with a substrate (core [C] or passive [P]).

For instance, an HDI printed board with two layers of HDI on one side of the core and one layer of HDI on the other side of the core would be 2 [C] 1.

The following definitions apply to all forms of HDI. Blind vias may exist in all types.

  • TYPE I 1 [C] 0 or 1 [C] 1 – with through vias connecting the outer layers

  • TYPE II 1 [C] 0 or 1 [C] 1 – with buried vias in the core and may have through vias connecting the outer layers

  • TYPE III ≥ 2 [C] ≥0 – may have buried vias in the core and may have through vias connecting the outer layers

  • TYPE IV ≥ 1 [P] ≥0 – where P is a passive substrate with no electrical connection

  • TYPE V Coreless constructions using layer pairs

  • TYPE VI Alternate constructions