barcode scanner in asp.net 2nd Button Plate. Art .012 over drill size. Plating Thickness. .6 mils. in Software

Create QR Code ISO/IEC18004 in Software 2nd Button Plate. Art .012 over drill size. Plating Thickness. .6 mils.

2nd Button Plate. Art .012 over drill size. Plating Thickness. .6 mils.
Decode QR Code In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
QR Code Drawer In None
Using Barcode generation for Software Control to generate, create QR Code 2d barcode image in Software applications.
1st Panel Plate entire panel surface and holes .7 mils minimum
QR Code JIS X 0510 Recognizer In None
Using Barcode decoder for Software Control to read, scan read, scan image in Software applications.
QR Code ISO/IEC18004 Creator In Visual C#
Using Barcode generator for .NET framework Control to generate, create Quick Response Code image in Visual Studio .NET applications.
FIGURE 27.27
Denso QR Bar Code Creator In Visual Studio .NET
Using Barcode encoder for ASP.NET Control to generate, create QR Code image in ASP.NET applications.
Painting Denso QR Bar Code In .NET
Using Barcode creator for .NET framework Control to generate, create QR Code ISO/IEC18004 image in VS .NET applications.
Pre-hole-fill plating.
QR Code 2d Barcode Creator In VB.NET
Using Barcode encoder for Visual Studio .NET Control to generate, create QR Code 2d barcode image in .NET framework applications.
EAN-13 Supplement 5 Printer In None
Using Barcode generation for Software Control to generate, create EAN13 image in Software applications.
27.3.5.3.2 Hole-Fill Process. Once the prefill-plating process is complete, the next major step is the actual hole-fill process. The fill materials can be divided into two major categories: conductive and nonconductive. A generic hole-fill process flow is shown in Fig. 27.28. The specific equipment and technique can vary by the material type used.The method chosen to apply the material in the holes can be influenced by many variables such as material cost, pot life, viscosity, equipment resources, and the quantity of panels to be processed. Some hole-fill materials lend themselves to a variety of fill methods. Some of the common hole-fill
DataMatrix Generator In None
Using Barcode printer for Software Control to generate, create ECC200 image in Software applications.
Drawing EAN / UCC - 13 In None
Using Barcode encoder for Software Control to generate, create GS1-128 image in Software applications.
PRINTED CIRCUITS HANDBOOK
Drawing Code 3 Of 9 In None
Using Barcode creation for Software Control to generate, create USS Code 39 image in Software applications.
Make Code 128C In None
Using Barcode drawer for Software Control to generate, create Code 128 Code Set A image in Software applications.
PWB VIA FILL APPLICATION (Generic Flow) (Sample Fab Process Starting from metallization)
Encoding Identcode In None
Using Barcode generation for Software Control to generate, create Identcode image in Software applications.
Encode DataMatrix In .NET Framework
Using Barcode creation for Reporting Service Control to generate, create Data Matrix image in Reporting Service applications.
Surface Prep (Chem or Mech)
Print UCC - 12 In Objective-C
Using Barcode creator for iPhone Control to generate, create UPCA image in iPhone applications.
Draw Bar Code In Visual Studio .NET
Using Barcode generator for Reporting Service Control to generate, create bar code image in Reporting Service applications.
Rinse
Code128 Decoder In Visual C#.NET
Using Barcode reader for VS .NET Control to read, scan read, scan image in .NET framework applications.
Code 128 Code Set A Drawer In None
Using Barcode maker for Office Excel Control to generate, create Code128 image in Office Excel applications.
Via Fill Application Methods: : Manual Screen Print Automated Screen Print (Vacuum Assist) Pressure Injection (Vacuum Assist) Roller Coater
Data Matrix 2d Barcode Maker In Objective-C
Using Barcode creator for iPad Control to generate, create Data Matrix image in iPad applications.
Decoding DataMatrix In Visual C#.NET
Using Barcode reader for .NET framework Control to read, scan read, scan image in VS .NET applications.
Bake (Moisture Removal)
Apply Fill Material
Pre Cure
Final Thermal Cure
Planarize
Inspect Fill
Continue to Pre Plate or Image
FIGURE 27.28 Generic via fill application flow.
application methods are noted in the flowchart in Fig. 27.28.Application guideline parameters should be followed as noted in the respective material supplier data sheets. Via-hole filling may be considered a finesse process due to its sensitivity to variables that occur from design to design and the availability of support equipment to perform the process. The various application methods each have advantages and disadvantages associated with the technique employed. When a fabricator is screen printing, a mask sized just over the hole size keeps excess material from being applied to the surface. Screen printing with a dot mask using a back side receiving template with open holes sized just over the plated hole diameter yields a domed fill bump. These bumps can act as a visual indicator similar to a button plate pad to indicate when the planarization is flush to the surface. Other methods include roller coating modified to squeegee excess material off the surface of the panel. Commercially available equipment designed specifically to apply fill material is now available. One such machine uses a pressureassisted injection method to force material into the holes under a vacuum. The principal advantage of this technique is the ability to reduce the opportunity for void entrapment. Figure 27.29 illustrates an example of how the filled structure forms with successive steps for a noncap-plated fill process. Note in this example how the surface button plating is mostly removed at the planarization step. Process development should be performed to target the optimum plating build-up method in regard to the process control of available planarization equipment. This means that whatever plating method is employed, both the deposit thickness across the panel and the net removal of deposit thickness as a result of planarization must be
MULTILAYER MATERIALS AND PROCESSING
Panel imaged to specific layer pattern
PROCESS FLOW
Panel after planarization to remove excess fill material and surface of button plate
Panel flooded with via fill material
FIGURE 27.29
Noncap-plated fill and planarization.
understood. Simple eddy current measurements of multiple locations across the panel are recommended prior to and after planarization sanding passes. Once the planarization is complete, the panels are ready for imaging and etching to allow typical process flow, depending on construction type. The plating method chosen should take into account the surface pattern and construction level of difficulty. Multiple plating cycles are often required if multiple filled structures occur on the same surface plane. Excessive copper plating complicates the imaging, so the starting foil thickness should be kept to a minimum. Figure 27.30 illustrates how the fill method forms from use of a method employing cap plating over the fill material. It should be noted how the copper thickness requiring etch can quickly build up, making pattern definition difficult. 27.3.5.4 Specifications. The industry has now released a design guideline document outlining via protection classifications, including the hole fill as described in this chapter. The IPC4761, Design Guide for Protection of Printed Board Via Structures, has established via-protection techniques, creating specific types identified as Types I through VII. IPC-4761 contains many combinations of techniques where an added material is utilized to plug, tent, cover, or fill a via structure. Many of the techniques established are used in Class 1 and 2 hardware or where circuit card assembly consideration is the primary focus. Many of the 4761 viaprotection types are of lower cost and lesser complexity than are those used for hole fills. The designer is encouraged to consult the application guide included in Table 5-1 of IPC 4761 to narrow the selection prior to layout and specifying a method. The via fills described in this chapter fall under the Type V and VII classifications. These types have been the focus for developing performance-based requirements as reliability data have become available. Amendment 1 of the rigid board performance specification IPC-6012B will introduce requirements for maintaining a minimum wrap copper. The specification limit is being established at 0.0005 in. minimum wrap as verified at cross section. This is considered a conservative value resulting from the nonuniformity of the process. Correlation data have revealed that coupons on the panel perimeter rarely match that of the actual product. Uniformity of the planarization across the entire panel is difficult, so a conservative value at cross section was established to ensure that the part maintains wrap copper. The reliability data gathered support this value due to the additional manufacturing risk that can occur from the added fabrication steps. However, some data collected in MRB action and assessment indicate that wrap copper as low as 0.0002 in. is acceptable for some end-use environments. It is likely that future revisions of
Copyright © OnBarcode.com . All rights reserved.