http://en.micro-ef.com/solution/ zh-cn Rss Generator By 3.0 biz#20200101 http://en.micro-ef.com/f2/126.html http://en.micro-ef.com/f1/97.html from this diagram, we can see that when the area ratio is greater than 0.7, the percentage of solder paste release volume is also higher than 80%, and when the area ratio is below 0.5, the release percentage is less than 60%. in the area ratio of 0.5-0.7, its release percentage is between 60-80%. the data were obtained from an electroformed template. when the area ratio is below 0.6, we can see that the deviation of volume ratio starts to increase rapidly. the reason for this problem is that at this point there are more openings or blocked openings. as more openings are blocked, this also results in an increasing number of defects in the 0201 component as the area ratio decreases. the following diagram shows the relation between the number of defects printed and the area ratio of the 0201 component printed with an electroformed template. (see figure 7)
as can be seen from the diagram above, when the area ratio is greater than 0.65, the number of defects begins to increase near 0.625. at about 0.565 of the area ratio, the number of defects began to increase considerably.
another problem in the 0201 manufacturing process is the choice of template type, that is, whether to choose an electroforming template or a laser cutting template. the laser cut template is drilled through the laser and then polished to remove the rough part of the hole wall. electroforming templates are made by forming technology, which allows for very smooth pore walls, which is very beneficial to solder paste release. the main problem with electroforming templates now is that they cost 2-3 more than laser cutting templates. from the two templates in the 0201 component printing test can be late, the amount of electroforming stencil printing paste is higher than the laser cutting template. the release ratio of the electroformed template is generally around 85%, while the laser cut mode is between 70-75%. in the experiment, we found that the number of defects appearing in the laser cutting template is higher than that of the electroforming template. therefore, the influence of all aspects, in production, if conditions permit, should be preferred choice of electroforming template. electroforming templates are recommended in the 0201 element process.
effects of 2 and 0201 components on patch equipment
bonding is considered the most important part of the entire 0201 process. since the mount system absorbs 0201 components from the feed system, visual only and accurate mount components, care must be taken in setting up this process. basically, the 0201 mount process involves four separate actions:]]> http://en.micro-ef.com/f1/96.html in the process of smt production, the printing of solder paste is usually the first step and the most critical process. because statistics show that in the process of smt production, 60%-70% welding defects are related to the printing of solder paste. in the printing process, there are several important aspects: solder paste, templates, printing equipment parameters. here we mainly discuss the impact of the following 0201 on template design.
first of all, introduce three commonly used methods of template production: chemical etching, laser cutting, electroforming molding. the chemically etched openings are bowl shaped, release performance of solder paste is not good, and the opening is easy to plug, so it should be cleaned regularly, to template precision is relatively low, usually used for big element spacing 20mii, but its cost than the laser cutting and electroforming are low; laser cutting with laser template cut an opening on the ladder of nature, is conducive to the solder paste release, but not the hole wall of electroformed template is smooth, recommended for the element spacing less than 20mil the price between the chemical etching and electroforming: electroformed stencil aperture is trapezoidal, rational and solder paste release, smooth hole wall very conducive to solder paste release, usually used for fine pitch and ultra fine pitch printing, with good wear resistance and long service life, the most expensive price in three weeks, making longer period. this template is suitable for 0201 components. here is a sketch of the three templates.
two important parameters in the template are the area ratio of the opening and the width to thickness ratio. (see below) general requirements for a width to thickness ratio of >1.5, area ratio >0.65.]]> http://en.micro-ef.com/f3/84.html http://en.micro-ef.com/f3/83.html smt has become the mainstream assembly technology since 80s, and remarkable progress has also been made in halftone technology. today, vendors can design a mesh using multiple materials and manufacturing technologies to meet the most challenging assembly technology trends: precision spacing technology, component miniaturization, and intensive circuit boards.
in addition, halftone technology is now used in a full range of mass extrusion printing materials. the screen designer has in-depth understanding of perforation size and shape influence on material deposition, prompted the emergence of new technologies (and will continue to emerge, the platform and screen printing) technology into the application field of every kind of, such as adhesive coating and wafer bumping.
the mesh has two main functions, regardless of the material or manufacturing process used. the first is to ensure that the coating material is accurately placed on the substrate, such as solder paste, solder paste or sealant; and second is to ensure that sizing and sizing are suitable.
halftone material and manufacturing
the most widely used mesh material is metal, mainly stainless steel and nickel. in recent years, a variety of plastic materials have gradually been accepted. screen manufacturing technologies include chemical etching, laser cutting and electroforming. with a brief look at these materials and processes, it is found that manufacturers can choose from a wide variety of mesh boards to meet specific application requirements.]]> http://en.micro-ef.com/f2/81.html why stencil printing method?
the industry's three most famous wafer projection methods - screen printing, evaporation and sputtering or electroplating - each has its advantages and disadvantages (table 1). the choice of method, in addition to the company's technology roadmap, the more important is the need to consider many parameters including convex space, convex height, wafer substrate, wafer thickness, wafer size, convex consistency, and raised material.
equipment and materials
the wafer mount printing method is designed to be compatible with the standard surface mount assembly line tool, so no additional investment is needed to upgrade or retrofit existing large equipment.
the screen press, however, should be equipped with sophisticated optical devices. the alignment system shall be able to identify non-standard reference points on the wafer to be processed, including pads, corners, special marks, markings, or other metallization features contrasting to the background coverings.]]> http://en.micro-ef.com/f2/80.html preface
a number of important design factors must be considered in order to ensure that the wafer to wafer process is satisfactory to a desired level.
screen printing
screen printing technology using standard surface mounting equipment is a cost-effective program for bonding wafer raised pads in simple and mature process conditions. with this method, different applications need different customized design guidelines, and compliance with specific equipment, materials and process instructions, to establish stable and high yield of the wafer bumping printing and reflow process.
parameters affecting the good rate]]> http://en.micro-ef.com/f1/73.html the application of 0201 component has a great influence on the design and manufacture of printed circuit board. its main influence is the design aspects, including pad design, component spacing and wiring design. the 0201 component requires smaller pads, finer and denser wiring, and smaller component spacing. for these changes, technically feasible, but the direct impact on the production costs of pcb, is a substantial increase in costs. let's discuss in detail the impact of 0201 on the pcb component spacing and wiring design.
1.1 component spacing and wiring design
the main reason for using 0201 components is to save space on pcb. this allows more components to be designed on the pcb to increase product functionality and reduce product size. the benefits of the 0201 component include reduction in component spacing in addition to its reduced size. this saves space further. some manufacturers and research institutes have done research in this area, and the results show that the use of 0201 component pcb saves 60% more space compared with 0402 of pcb. the results also show that the minimum distance between components can be as small as 6mil.
currently, for component 0201 applications, the requirement for the component spacing of the contract manufacturer is 16mil. the regular distances we can see are 8mil, 12mil, 16mil, and 20mil. of course, the smaller the space between the components, the more space it saves. but the smaller spacing has great influence on the accuracy of the patch equipment, the accuracy of the template and the design of the pcb wiring. the smaller the component spacing, the higher the accuracy of the placement machine, and the smaller the opening spacing on the template, the more difficult it is to make the template. if you want to achieve 8mil spacing, you need to make some improvements in the wiring of pcb.
first, take a look at the line width and line distance of the pcb cabling. see table 1.1-1.3]]> http://en.micro-ef.com/f1/72.html preface
with the development of smt towards fine spacing components, the density of smd package pins is becoming more and more dense, and the trend of decreasing package size has posed a severe challenge to solder paste printing. statistics show that more than 50% of the assembly defects are caused by solder paste printing 3, therefore, solder paste printing has become a major factor affecting the quality of smt assembly.
as we all know, there are 3 main factors that affect the quality of printing in solder paste printing: equipment, solder paste selection, and stencil selection. equipment is mainly purchased according to the overall requirements of the production line, this article does not do research. the main factors considered in the selection of the template are template design, opening design and template printing. the template manufacturing technologies include chemical etching, laser cutting, electropolishing, electroplating and electroforming. focus on the selection of solder paste, solder powder size, alloy can provide a certain content to paste supplier requirements, select several suppliers of solder paste samples in the experiments, the best judgment paste suitable for the enterprise products on the basis of experimental data.
template selection
formwork thickness and opening design]]>