Laminated substrates

Other Durable Applications. Other durable appHcations such as interlinings and coating/laminating substrates do not appear to offer much near-term opportunity for growth for spunbonded fabrics. In interlinings, however, spunlaced nonwovens have received wide acceptance because of the outstanding drape and softness previously unavailable from any other fabric. 

Several MCM designs have been developed MCM-C (ceramic substrate), MCM-L (laminate substrate), MCM-Si (silicon substrate), and MCM-D (deposited dielectric substrate). For MCMs, according to Feger and Feger [76], polymers are becoming the dielectric materials of choice because ... 

Lastly, adhesives are used to dissipate stresses that may be generated from thermal excursions, mechanical shock, vibration, or moisture. Specially formulated adhesives are effectively used as underfills for flip-chip devices and ball-grid-array packages to compensate for mismatches of expansion coefficients among the solder, the silicon chip, and the ceramic or plastic-laminate substrate. Low-stress adhesives are also used to attach fragile devices such glass diodes and to dampen stresses due to vibration. 

Of the mass-transfer dispensing methods, screen printing and stencil printing are the oldest and most widely used. Screen printing has been used for over 40 years in the electronics industry to apply thick-film conductors, resistors, and dielectrics in fabricating circuits on ceramic and plastic-laminate substrates. Screen printing is also used as a batch process for depositing electrically conductive and insulative adhesives to interconnect devices on thin-film and thick-film hybrid microcircuits. 

Rigid laminate substrate (with or without soldermask), wire bonds, over-molded... 

Mylar. Magnetic media packaging, laminating substrate for flexible packaging, boil-in-bag, lids, microwave applications, oven wrap, and snack bags.fi 1... 

When high cohesion strength levels are required of coated or laminated substrates made of polyester, polyamide, or aramide fibers bonded to soft PVC, adhesion promoters have to be used. 

Sintered silicon carbide bonded to plastic laminate substrates reinforced with glass or Kevlar fabrics can be used as ceramic armor to defeat armor piercing projectiles [287]. 

Film Fill FF7673/ AI Technology Epoxy insulative film, quartz-filled, 0.7 W/m-K thermal conductivity 150°C, 10 psi, 1 sec Flip-chip to ceramic or laminate substrates... 

Rigid laminate substrate (with or without soldermask), wire bonds, over-molded Small outline, low profile (1.0 mm), enhanced electrical performance over 2.4 GHz, JEDEC moisture sensitivity level (MSL) 3 Plastic thin fine pitch quad flat no lead package (P-TFQFN), plastic thin shrink small outline no lead package (P-TSSON), and fine-pitch BGA, FBGA (National) Portable applications, flash memory... 

Metal-to-metal laminate test for large bonded areas but may also be used with plastic subsfiates Specifically for adhesives used in plywood laminate constructions Specifically for wooden (two-ply) laminate substrates... 

Variable film resistors are made with carbon composition films, usually on a paper laminate substrate, or with metal glaze films on a ceramic substrate. It is complicated to trim these resistive elements. Therefore, the tolerance on the resistance of film variable resistors is usually high, in the order of 20%. For most applications, however, this is no problem. 

Cover Photo Automated dispensing of conductive adhesive for large-area die attach on laminated substrate. (Courtesy Asymtek)... 

The problems of thermal coefficient of expansion (TCE) mismatch between silicon chips that are directly flip-chipped onto a laminate substrate have been effectively eliminated by using a filled epoxy underfill encapsulation technique between the chip and the substrate (see... 

These trends have led to the larger use of nonorganic base substrates, such as aluminum and soft iron. In addition, alternate ways to create boards have been developed. These will be discussed in this chapter, along with the traditional board structures and processes. The terms printed wiring board, PWB, and board will be used synonymously. Also, the words laminate, substrate, and panel will be used interchangeably. 

This class of PCBs is a variation of the multilayer package. A circuit board is constructed by etching a pair of power layers back to back on a laminate substrate. A layer of partially cured, still sticky laminate is bonded to each side of this power plane structure. Discrete wiring is rolled into this sticky adhesive in patterns that will connect leads or serve as access to surface-mount component pads. 

Punch forming is used in the manufacture of very low cost, single-sided PCBs such as are used in many consumer electronic products. The process involves printing and etching the conductor patterns on one side of a laminate substrate, usually paper-reinforced epoxy. All holes are punched in a single stroke by a die containing a pin and opening for each hole. The PCB outline is formed in a second die that blanks it from the panel in which it is processed. 

The laminate substrate material is constructed of supporting fibers (most commonly a glass fiber weave) and a resin (most commonly an epoxy compound). Finished board thickness may range from 0.010 to 0.300 in or thicker, with the most common panel thickness ranging around Vi6 (0.0625 in). 

The individual sheets of processed tape used in a substrate are collated and aligned by using tooling holes aligned to the via and circuit pattern in each layer of tape. The multilayer stack is then laminated under elevated temperature (70 to OO C) and pressure (2000 to 6000 Ib/m ) to bond the individual layers into one cohesive stack. Two distinct methods of lamination are used isostatic and uniaxial. Isostatic lamination is used to laminate substrates containing cavities since it is critical to attain uniform applied pressure to surfaces as well as bottoms of cavities. Uniaxial lamination is used for flat substrate designs. 

Experience with PBCAs has shown that the relatively high die stiffness and the flexibility of the laminate substrate generally cause first thermal cycle fatigue failures in the ball closest to the die shadow. Despite the overall economy of elements in each strip model, selective mesh refinement was used to concentrate highly refined elements in the solder joints where failure was anticipated. 

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