In the past half century, the production cost of semiconductors has dropped dramatically, while production technology has continued to improve, and productivity and product yields have continued to increase. I remember the vice president Tom Morrow said: Today's LEDs also have the same market driving force, LED will be a fast pace to high-brightness, low-cost popularization. If the theoretical basis of this law is not keeping up with the pace of double the performance per month, it will be difficult to compete in the market; based on this, it will keep up with the rhythm of the continuous reduction of the production cost of LED products in the market. Another important indicator of the survival of LED companies.
As an important part of the industry, LED packaging, with the gradual reduction of the price of finished products, under the premise of keeping up with the industrial development technology, it is necessary to do its own cost control, in order to occupy a place in this competitive industry. Therefore, in recent years, the prices of the main raw materials such as chips, phosphors, and brackets have been greatly dived, and the price has been competitive for several times, and there is almost no room for compression. Among them, although the original cost of the package gold wire is small, but on the basis of the decline in prices of other materials, the proportion has gradually expanded, so the selection of packaging wire replacement materials has become an important part of the packaging industry can not be ignored, so since 2012 Since the beginning of the year, many packaging industries have followed the footsteps of semiconductor packaging to actively look for package wires such as silver and copper.
In the past ten years, the market of gold has gradually increased, which has accelerated the proportion of the cost of gold wire. Therefore, the use of silver, which is also a platinum group element, as an alternative material for alloy wire has been born. Gold is a platinum-based noble metal, in which silver and gold are the first choice for alloying elements, and platinum and palladium are neighboring elements as trace auxiliary elements. Silver alloys are developed by material manufacturers under such a basic background. come out.
The price of silver-based package alloy wire can be more than 85% lower than that of pure gold packaging wire. Compared with the overall LED lamp bead product, it has at least about 6%-15% reduction according to product structure. This large decline also deeply stunned the packaging industry. Also, because the silver alloy is easier to weld with the silver-plated bracket, the change of the bond crystal structure is also 15-20% higher than that of the pure gold wire after the wire bonding; the brightness of the silver alloy wire product can also be increased by about 1%- Around 3%, these are the benefits of using silver alloy wires.
However, the high-silver alloy wire also has its own disadvantages, because the chemical properties of silver are more active than gold, and it is easy to oxidize and vulcanize when exposed to air; the range of parameter variables corresponding to the wire bonding machine is reduced, which requires the wire bonding technical engineer to have A few of the welding wire has a lot of debugging skills.
In addition, the high-silver alloy wire occasionally has the first solder point ball golfing phenomenon, so for the application of the high-silver alloy wire, a nitrogen gas blowing device is selectively used as the first solder joint ball for the welding wire. However, depending on the product design, packaging equipment and supporting equipment, there is no need for nitrogen assistance. Generally, it is not necessary to use nitrogen as a wire bonding aid in PCB products.
Metal oxide semiconductor field effect (MOS) transistors can be divided into N-channel and P-channel. P-channel silicon MOS field-effect transistors have two P+ regions on the N-type silicon substrate, which are called source and The drain is not conductive between the two poles, and when a sufficient positive voltage (gate ground) is applied to the source, the surface of the N-type silicon under the gate exhibits a P-type inversion layer, which becomes a channel connecting the source and the drain. . Changing the gate voltage changes the density of the holes in the channel, thereby changing the resistance of the channel. Such a MOS Field Effect Transistor is called a P-channel enhancement type field effect transistor. If the surface of the N-type silicon substrate is free of gate voltage, the P-type inversion layer channel already exists, and the appropriate bias voltage can increase or decrease the resistance of the channel. Such a MOS field effect transistor is referred to as a P-channel depletion field effect transistor. They are collectively referred to as PMOS transistors.
P Channel Mosfet
P Channel Mosfet,P Channel Power Mosfet,Field Effect Transistor,Field Effect Transistor Symbol
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