Speaking of CSP, the first thing that entered the LED eye and was fiery was the concept of “free packagingâ€. The earliest CSP was only used in some flash markets, and now it is gradually increasing in the backlight market. The so-called package-free package does not really eliminate the packaging process, but advances part of the packaging process to the chip process stage, that is, flip-chip directly seals the pad to the bottom of the package, without gold wire, without bracket, simplifying production. Process, reduce production costs, package size can be made smaller, and the same package size can provide more power, that is, chip-level package (referred to as CSP, too many definitions of this article, not mentioned here).
CSP-LED device package cross-section
If you have been paying attention to the development of CSP, you will find that when the concept of CSP is gradually heated, the words like package-free, CSP, NCSP and WiCop instantly win the eyes of most people, but what exactly are they? What is the connection between each noun?
What is NCSP?
In the past few years, the international giants of high-power LEDs have focused on improving the original ceramic packaging technology. With its advanced high-power flip chip or vertical structure chip, the package has been miniaturized to reduce the cost of ceramic substrates and lower. The cost pressure of production efficiency and the ability of the chip to withstand large current densities.
The result is that without reducing or even increasing the luminous flux, they change the original 3535 package to 2525, and then shrink to 1616 or even smaller, so that the size of the LED approaches the size of the chip itself, because close to the CSP, Therefore, the name is Near Chip Scale Package, referred to as NCSP.
NCSP-LED device package cross-section
In this regard, Tiandian Optoelectronics Cheng Manager said that CSP refers to the unsupported package, such as Seoul's WiCop, the package size is the chip size, and NCSP refers to 20% larger than the actual chip, there is a cup or bracket .
Since entering 2015, the CSP wind in the LED industry has been surpassed by waves, and is considered to be a revolutionary product of LED packaging. When the LED wind direction began to shift, many companies began to lay out CSPs, but not all companies have the capital to make up their minds. Why do you say this?
As a packaging company, it has been making great efforts to install LEDs in the past, and has made great progress in the process, and has always had good performance in the existing market. When the concept of CSP came, some large listed companies stepped in and took the lead and did not want to miss it. As a part of small and medium-sized formal enterprises, the original revenue is limited. If you invest in CSP and deploy equipment, there are great risks and uncertainties in both capital and product development.
Moreover, the current development of CSP is still in its infancy, and the advantages are not yet obvious. In this regard, Hongli Optoelectronics Lei Lining also said that although both CSP and WiCop have been fired hot, compared with many current packaging forms, there are mainly several burning points in the packaging form of CSP. First, the light effect design compares with the traditional dressing process. It does not have the advantage of cost performance. For example, under the same power and light effect, the positive chip has advantages due to the yield and maturity. When the same light effect is the same as the luminous flux output, the formal wear also has advantages; secondly, the lamp manufacturer uses the SSP of the CSP. Many problems.
What is the relationship between NCSP and CSP?
The NCSP technology relies on a flip-chip chip (Flip Chip) to solder the flip chip to a ceramic or flexible substrate by eutectic soldering, and then apply a phosphor layer on the sidewalls of the sapphire and the chip as a light-emitting window. A five-sided light source is formed. Due to its maximum luminous flux per unit area (high optical density) and the largest ratio of chip to package cost (low package cost), it is expected to open a subversive breakthrough in cost performance.
When the size of the ceramic substrate is almost as large as the chip size, it gradually loses the function of assisting the heat dissipation of the LED. Conversely, if the ceramic substrate is removed, a thermal interface is removed, which facilitates rapid heat transfer to the outer circuit board. At the same time, as the flip chip matures, the function of the ceramic substrate as a re-distribution of the PN electrode line as an insulating material is no longer needed. In addition to the protection of the LED on the mechanical structure and thermal expansion mismatch, the important functions of the ceramic substrate for electrical isolation and heat conduction of the chip have been substantially lost. Therefore, the substrate-free CSP packaging technology came into being.
NCSP can be said to be based on the immature nature of CSP technology and the transition of market demand. From the current development of LED, on the one hand, due to the intensification of price wars, companies have reduced the size of materials to reduce the cost of materials, and launched a more cost-effective product, making the product size smaller, on the other hand, the new product CSP was It is considered to be the latest generation of cost-effective products, and the current technology is not yet mature, which has given birth to the transitional product NCSP.
Of course, for any new technology or product to mature, it must go through a cycle and eventually mature. If the CSP is substrate-free, the NCSP may have its necessity before the substrate-free CSP matures.
For the CSP with the substrate, Dr. Dehao Runda Mo Qingwei said that he has lost the original intention of developing this technology. Because the initial background of CSP technology is to streamline the process and reduce the process. If the substrate still exists, it is contrary to the original concept of admiration.
What is Wicop?
Wicop's name from Seoul Semiconductor is taken from the English acronym for Wafer Level Integrated Chip On PCB. This technology is a product that breaks through the limitations of CSP, which is often said, and realizes a new concept of unpackaged LED. Since the chip is directly connected to the PCB, the solid crystal, the bonding wire and the like required by the conventional LED packaging process are not required, and the chip size and the package size are 100% identical because there is no intermediate substrate, which is an ultra-small, high-efficiency product. Extremely high optical density and thermal conductivity.
Wicop-LED device package cross-section
The advent of this new product completely overturns the traditional LED package production mode, eliminating the need for LED packaging (Die Bonding), wire bonding (Wire Bonding) and other production processes, no longer need to be used as LED package The new concept WiCop is a new concept for the main components of the frame (Lead f rame), gold wire (Gold wire) and other materials.
In this regard, Hongli Optoelectronics Lei Lining said that in fact, the bare crystal CSP is simply divided into two categories, the first category is the finished chip package type; the second largest category is the epitaxial package type. The chip-package type is characterized in that the chip manufacturer has passed the test of the film-packed product and then undergoes a solid-crystal process (chip array machine), and then passes through the white light process (spraying, Molding, lamination, etc.), and then the latter segment is divided. Packages, etc.; the second major category is the epitaxial packaging type, and some are also defined as WiCop, which is a packaging technology on wafer. However, in the case of "free-package", it means that it is a gimmick that is produced by a manufacturer with chip production line resources or equipment resources.
In this regard, Dehao Runda Vice President Mo Qingwei said that WiCop is not a new technology at all, in fact, it is only CSP at the extension level. And there are still many technical challenges in the current level of CSP.
It can be seen that the true CSP packaging technology eliminates the need for an additional sub-mount or lead frame and directly fits on the carrier. Therefore, the industry also calls it a white light chip. After the package substrate is removed, the package area is further reduced, and the light extraction angle and optical density are improved. Moreover, the gold-tin (Au-Sn) eutectic soldering required for the die bonding process in the conventional flip chip packaging technology is reduced to low cost. Lead-free solder soldering further reduces packaging costs. However, in terms of the current packaging plant technology, it is not easy to realize the complete elimination of the substrate. Therefore, most of the packaging companies currently use the flip chip bonding technology with the substrate when producing the CSP product. Therefore, in a strict sense, most CSPs on the market can be attributed to NCSP products, and existing CSP packages exist based on flip-chip technology.
In this regard, Dr. Dehao Runda Mo Qingwei also said that for the CSP without substrate, it is currently known as Seoul Semiconductor, Dehao Runda, Samsung and lumileds.
What is the relationship between CSP and Wicop?
For WiCop, Seoul Semiconductor previously said that WiCop is a more simplified design than CSP. There is no wafer, packaged, solid crystal, gold wire and other wafer-level packaged LEDs, which only need to press the fluorescent film on the chip. . But what is its relationship with CSP, Seoul Semiconductor uses the formula "CSP≠WiCop".
However, Mo Qingwei, vice president of Dehao Runda, said that from the perspective of the structure of CSP, WiCop is actually a CSP free of substrates. It's just based on the package on the epitaxial wafer, and the CSP is based on a single finished chip package. Although the process is different, it is just a different csp structure. Moreover, the structure used by CSP companies is also different, each process is different, and the structure used will vary depending on the application field.
In fact, there are many ways to implement CSP white light. The mainstream technical route on the market is to cut the wafer, perform phosphor coating on the square sheet, and then test and tape. The core process is around the coating technology of phosphors, including spin coating, spray coating, sealing, printing, and fluorescent film patching. Each process has its advantages and challenges. This process is similar to the traditional packaging process and is suitable for making five-sided CSPs.
There is also a single-sided illumination type CSP that applies phosphor on a wafer (wafer) for most or all of the package test procedures, followed by singulation to make a single component. This packaging process is also known as the Wafer Level Package (WLP). However, the phosphor coating achieved by such a process covers only the upper surface of the LED chip , and the blue light leaks through the sapphire from the periphery, affecting the uniformity of the overall color space distribution after packaging.
Regardless of the process, CSP will not eliminate the life of the packaging company. In this regard, Hongli Opto-Relining also said that WiCop is a CSP for epitaxial packaging, but no matter which level of packaging, packaging companies can do packaging, just to buy a finished chip or buy a whole wafer to package .
In short, whether it is NCSP, CSP or WiCop in the future, whether it can play a revolutionary role, but it does omit some links of the original technology, it is a technological advancement. As Dehao Runda Mo Qingwei said, don't regard csp as a beast, it will not seal a throat. It is an innovation in the LED industry, but also a challenge, but at the same time it is a new opportunity. !
Float Charge
Nickel Cadmium Battery – 1.30V per cell
This will enable the battery to recover its capacity quickly and reduce the water consumption. In this aspect, it will reduce the topping up frequency and storage of water.
Boost Charge
Nickel Cadmium Battery – 1.60 V per cell
Equal Charge
Nickel Cadmium Battery– 1.65 V per cell
Nickel Cadmium Battery Charger
Nickel Cadmium Battery Charger,Smart Battery Charger,Electric Stacker Battery Charger,Rechargeable C Batteries
Xinxiang Taihang Jiaxin Electric Tech Co., Ltd , https://www.chargers.be