DE2020587B2 - METAL-BACKED COMPRESSED LAYER FOR THE MANUFACTURE OF CIRCUIT BOARDS - Google Patents

Description

silk fabric is the case. This difficulty is not required if the structure is made of glass fiber fleece, as the laminate becomes more homogeneous.

3. Since the layer weave of the material is better than when using glass silk fabric, it is less prone to delamination during mechanical processing.

4. Since the glass fiber fleece has a weight per unit area between 50 and 100 g / m2, thin Laminates are manufactured without additional compensation layers, even if very tight tolerances are observed graze, which is generally required for glass silk fabrics.

5. By selecting a suitable resin content of around 40 to 50 ° / o, the laminate can be adjusted so that its coefficient of linear thermal expansion practically corresponds ^{to that of copper, 17 · 10 "6 degrees.}

This eliminates the annoying warpage - especially the one that is copper-clad on one side Laminates - largely reduced. Such a high resin content is essential for this purpose not applicable to conventional glass silk fabrics.

6. As is well known, glass silk fabrics can contain mechanical stresses which result in different Tension of the warp thread as well as based on the fact that through weaving of the weft thread a Qv t contraction of the fabric takes place. In the event of deviations from the Perpendicularity between warp and weft, d. H. when moving the fabric, further additional stresses can occur. This tension in the tissue can reinforce when impregnating the same and are reinforced in the manufacture of the glass silk Laminate pressed in with. The extremely annoying twist is based on this fiberglass-reinforced circuit boards, which occasionally occurs inevitably.

According to the invention, these difficulties can largely be overcome by using glass fiber fleece be avoided.

It has proven to be favorable in terms of compression technology when the laminate made of glass fiber fleece is used on both sides In addition, there is a cover made of fine glass silk fabric, which is useful with the same hardenable resin like the impregnated glass fiber fleece is resinated. Due to the double-sided fiberglass cover the sliding and floating of the fleece, which is high if used too early Can aufueten pressing pressure is reduced.

Application example 1. Structure:

55 ¹ Vo glass fiber fleece, consisting of about 90 "η Ε -glass with 9 inn filaments and a weight per unit area of 50 to 60 g / m2, 45% binder made of hardenable resin, consisting of

100 parts by weight of unmodified epoxy resin of epoxy equivalent weight 180 to 200, 44 parts by weight of aromatic di-

min as a hardener.

0.5 part by weight of BF _, - adduct as accelerator.

2. Impregnation:

The impregnation of the glass fiber fleece is done in a dip or roller squeeze process carried out a horizontal impregnation machine, using the binder specified above is dissolved in a suitable solvent.

3. Pressing:

The sheets of impregnated glass fiber fleece, cut to size, are optionally layered together with copper foil using two cover layers of impregnated glass fiber fabric, as described above, and solidified under pressure and temperature. The pressing temperature is 170 "C. the pressing * ° pressure 80 kp / cm ^s , the pressing time 2 hours.

As the curable resin, for. B. also phenolic, silicone, bisdiene or unsaturated polyester resins be used.

The metal lamination can also be applied subsequently to the pressed laminate, which is not actually metal-lined plate can be applied using an additive process.

Claims (1)

Raw state are very widely tolerated in terms of their thickness. Claims: The production of a 1.50 mm thick laminate with a fluctuation range of ± tO ⁿ / o in the nominal 1. Metal-laminated laminate plate with strength is practically impossible. a support body based on glass fiber for the production of 5 For these reasons, the production Positioning of printed circuit boards, characterized by a thin, closely-tolerated copper-clad layer, that the support body consists of a pressed material panels so far consistently with glass fiber fleece made of Ε-glass and with tissue or paper as a support or reinforcement curable resin is impregnated. material carried out. There are also attempts ? .. Metal-laminated laminated sheet after to became known, so-called glass fiber mixed papers Claim 1, characterized in that additional to be used as carrier materials. This glassy on one or both sides of the surface a mixed fiber paper consists of glass fibers and Cover with fine fiberglass fabric and are made using a cellulose is arranged. suitable binder in terms of paper technology 3. Metal-clad laminated sheet solidified after 15 dense fleece. This variant has become Claim 1, characterized in that this proved to be of little use, yes in these curable resin consists of an epoxy resin. Mixed papers with a cellulose content of at least 70 ° 0 4. Metal-clad laminated sheet according to and thus as the dominant part of the Claim 1, characterized in that the laminate has the character of one on paper Meiallkaschierung awarded from a subsequently built up in 20 laminates. In addition, the an additive / experience electroless or galvanic inhomogeneity of the mixed papers on the phase applied Layer consists. limit glass fiber paper fiber to impregnation problems, apart from the fact that the mixed papers were not interesting in terms of price. 25 Pure glass fiber fleece (cf. DIN 61850) as carrier material in copper-clad laminates have not yet been used because the nonwovens available on the market The invention relates to a metal-clad very loosely worked and only very little Have laminate with a support body for mechanical strength. Also are at Fiberglass base for making printed circuit boards. 30 of all known nonwovens the glass fibers are too coarse and Ev is known and customary to use fiberglass too long, so that laminates made from it To incorporate reinforcement material in laminates. difficult to drill or punch. Finding the production of high pressure laminates The present invention is the task thereby glass silk fabric, glass roving fabric and for the basis for the production of printed circuit boards the production of low pressure laminates also 35 drillable and punchable and at the same time twistable glass silk mats Use. The manufacture to find low-copper carrier material, which the Herferkaschierter glass fiber reinforced laminates made of thin and tightly tolerated metal previously made possible almost exclusively with laminated laminated plastic panels, This object is achieved according to the invention out because glass roving fabric for the printed circuit board 40 solved that the carrier body from a pure glass manufacture is way too rough. The use of fiberglass fleece consists of Ε-glass and with a hard silk mat (for a definition of the term, see DIN barten resin is impregnated. 61850) was occasionally attempted for price reasons. However, due to technical disadvantages, a specially processed glass fiber fleece made of paper does not have a similar quality, which is of general importance to about 90 °. Glass silk mat allows 45 glass fibers and about 10 ° η to consist of a suitable binder using the normally used binding agent, has proven to be very difficult to impregnate hardenable resins for the production of copper-clad resin solutions as a carrier material for horizontal and vertical impregnation machines, as solid-pressed plastic plates have proven to be excellent . That it has too little mechanical strength. Glass fiber fleece should only be made of Ε-glass. Therefore, the glass silk mat will mainly be at 5 °, the filaments should preferably have a solvent-free resin, such as 1. B. unsaturated maximum thickness of 9 μm. Polyester resins, impregnated and in this form When choosing a suitable hardened resin *, pressed under low pressure. z. B. based on epoxy resin, the copper Copper-clad polyester glass hard mat has the following technical advantages: partly for electrical reasons a certain 55, _. ,. ..., .. ... width found, the laminate usually '' ^It " ^{st mm} difference from glasse.denver.tark- still contains quite large amounts of filler. A ^te . ^{n Lamin} ? ^te "S ^ut . punchable, whereby its mechanical Pressing the impregnated mats in the high ⁿ ! ^sd ! ^{e and} thermal resistance is great Due to the ais already mentioned, pressure-pressing process is ^{that of} laminates on paper bases. low mechanical strength of the mats very 60 2. In addition to the punchability, the drill bar is also problematic, because the mats were torn under too high pressure speed of the material compared to that of more which leads to considerably large layers of glass fiber reinforced laminates Inhomogeneities in the material as a result of resin coatings - improved. It is well known that difficulties arise or glass enrichments on various th when drilling glass fiber reinforced laminates Places is coming. It is also difficult to adhere to 6 "; because the drill gives way when it that in the manufacture of printed circuits when piercing the laminate on districts usually required thickness tolerances, since the greater hardness meets, z. B. with the crossing mats dnerscits relatively difficult and on the other hand in terms of warp and weft threads of the glass