IPC-4101 Specification

The most commonly referenced specification for base materials is IPC-4101, Specification for Base Materials for Rigid and Multilayer Printed Boards. Historically, the National Electrical Manufacturers Association, NEMA, has also been used in specifying base materials. 

IPC-4101, Specification for Base Materials for Rigid and Multilayer Printed Boards. ... 

Revision B of the IPC-4101 specification was released in June 2006.The committee responsible for this specification worked hard to add material specification sheets that included some of the properties discussed in Chaps. 10 and 11 in regards to lead-free assembly. Table 11.6 summarizes some of the new specification sheets that include properties such as decomposition temperature, z-axis expansion, and time-to-delamination values. 

IPC 4101, Specifications for Base Materials for Rigid and Mnitilayer Printed Boards, Rev. B 06106 This docnment contains specification sheets for laminate materials nsed to mannfactnre PCBs for commercial and military apphcations. The minimum requirements for key material properties can be found in these specification sheets. 

One of the first classifications of base materials for printed drcnits (and other electrical components) was completed by the National Electrical Manufacturers Association (NEMA). NEMA s industrial laminating thermosetting products standard documents many of the materials used in printed circuits as well as specifications for some of their properties. Historical NEMA grades are outlined in Table 6.1 and cross-referenced with IPC-4101 in Table 6.2. Some of the commonly used materials have been FR-2, CEM-1, CEM-3, and, of course, FR-4. 

The most commonly used specification for base materials is IPC-4101. This specification presents a classification scheme and specification sheets for the various materials in use. Table 6.2 summarizes the various materials by specification sheet number. Each specification sheet in IPC-4101 includes property requirements for that particular material type. As these specification sheets are updated periodically, it is recommended that the latest revision of this document be reviewed. This is particularly true in light of new requirements for materials that must be compatible with lead-free assembly.Table 6.2 is presented for reference only and is not all-inclusive. UL94 comments in Table 6.2 reference the minimum flammability requirements for that material. Materials may exceed these minimum ratings. Also note that where a non-halogen-based flame retardant is used, it is shown along with the resin system description. Definitions of the UL flammability ratings are given in Chap. 8. 

Some of the properties documented in the specification sheets of IPC-4101 include Tg, copper peel strengths at different conditions, volume resistivity, surface resistivity, moisture absorption, dielectric breakdown voltage, permittivity, loss tangent, flexural strengths and arc resistance. These properties will be discussed further in Chap. 8. 

As IPC specifications are regularly reviewed and updated, it is recommended that the latest IPC specification be used for actual apphcations. However, an example of a laminate designation in IPC-4101 is ... 

TABLE 6.3 Metal Cladding Types Summarized in IPC-4101 (IPC-CF-148, IPC-4562, and IPC-CF-152 are Actual Metal Cladding Specifications) ... 

In addition to properties on the specification sheets, IPC-4101 includes class specifications for other properties as well. These include length and width, bow and twist, and thermal conductivity, among others. 

In summary, experience to date indicates that specification sheets 99 and 124 are suitable for a very broad range of applications. For lead-free applications, the user should consider these as the baseline. Simple low-technology PCBs or those that do not have stringent longterm reliability requirements may successfully use the materials covered by sheets 101 or 121, whereas very advanced products may need more stringent requirements, such as those covered by sheets 126 and 129. Finally, dways check for the most recent revision of IPC-4101, as new specification sheets will be added as more experience is gained and data are gathered. 

During the quahfication of a new laminate material, it may also become necessary to perform prepreg-specific tests to verify its quahty. The most commonly tested properties of prepregs are resin content, flow during mutilayer processing, and gel time. Details about additional properties and all corresponding test methods can be found in IPC-4101. 

The bare-board base materials are identified by using the classification system found in IPC-4101, which has specification sheets for various grades of material. The specification sheet is also known as a slash sheet since each material specification is preceded by a forward slash (/). Each sheet s heading typically identifies the resin system, the reinforcement, flame retardant, presence of fillers, as well as some performance parameters, such as glass transition temperature (Tg) or decomposition temperature (Tj). More detail is in Sec. 27.2.2. 

IPC-3406 Guidelines for Electrically Conductive Surface Mount Adhesive IPC-3407 General Requirements for Isotropically Conductive Adhesives lPC-3408 General Requirements for Anisotropically Conductive Adhesive Films lPC-4101 Specification for Base Materials for Rigid and Multilayer Boards lPC-4103 Specification for Plastic Substrates, Clad or Unclad, for High Speed/High Frequency Interconnection... 

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