Page 16


ManageMent www.us-tech.com


Plasma Treatment -- A Versatile Method of Surface Cleaning and Deposition


By Michael Barden, Head of R&D and Lead Scientist, PVA TePla America P


lasma treatments are a power- ful technique for solving chal- lenging surface issues, whether


through precision cleaning or by in- creasing surface wettability to pro- mote adhesion. Plasma can also be used to deposit a wide range of chemistries onto surfaces. When surface challenges arise


and engineers and production person- nel are tasked with evaluating plasma as a possible solution, they are quickly immersed into the physics and chem- istry behind the technology. But it also extends to how plas-


ma is applied to each part, the type and size of chamber, tooling options, and facility requirements. Like any investment in technology, plasma must be justified based on ROI, budg- et, throughput, and maintenance costs.


Considering Plasma With the right type and configu-


ration of equipment, the collective properties of the plasma (ions, elec- trons and radicals) produced in the


REFLOW


chamber can be controlled to alter the properties of surfaces without af- fecting the underlying materials. For example, surfaces can be etched by pure chemical etching, through phys- ical etching or through both chemical and physical etchings. In chemical etching, plasma-ac-


tivated gas species attack the materi- al surfaces, forming volatile deriva- tives of the material removed. In physical etching, ions in the plasma are accelerated towards the sub- strate surfaces. On their way to the substrate surfaces they may collide with other neutral atoms and mole- cules to ionize them, while the origi- nal ions may become neutrals. The ionized atoms and molecules


start accelerating toward the sub- strates and the newly created neutrals continue to head toward the substrate surfaces, maintaining their pre-colli- sion velocities. As a result, large num- bers of ions and neutral species bom- bard the substrate surfaces causing substrate material to be ejected. In fact, there are so many com-


See us at


SOLDERING SYSTEMS


SEMICON West Booth 6168


binations and potential chemistries involved that equipment vendors, such as PVA TePla in Corona, Cali- fornia, often host customers to an- swer questions and help them select the right tool for their applications. While there is much to learn


about the physics of plasma, most cus- tomers are more focused on the results of the process and how the modified surfaces can be tested. Even more questions are targeted at the type of tool that should be purchased, the fa- cility requirements and overall costs. Many customers are less inter-


ested in how the plasma is generat- ed, caring more about cost and throughput.


Equipment Selection Although there are atmospheric


systems for in-line manufacturing, the majority of plasma treatments are conducted in low-pressure vacu- um chambers. Most low pressure plasma systems involve a chamber, vacuum pump, power supply, elec- trodes, the system interface and con- trol, electrical components, gas/mono - mer distribution components, and ex- haust system. In other words, if the vacuum


chamber will be used for chemical deposition, surface modification, etching, or cleaning, it will likely re- quire a slightly different gas delivery system, power generator, tempera- ture controls, and chamber pressure. There are three primary cost drivers in any plasma system: the type and size of the chamber, power generator and vacuum pump. The vacuum chamber is a rigid


enclosure from which air and other gases are removed by a pump. The size of the chamber is dictated by the largest size of substrate that will be processed.


Vacuum pumps come in wet and


dry configurations. Wet pumps use low vapor pressure oil to seal in gas,


FALCON ULTRA PROFILE 1200 Small Footprint • Efficient Power Use


Consistent High Yields • Precise Temperature Gradient


Find it once again at www.us-tech.com


SIKAMA INTERNATIONAL, INC. www.sikama.com


See at SMT Hybrid Pkg., Booth 4-427


Lost your news item of interest?


creating a vacuum and also lubricat- ing its components. Dry pumps do not use any oil to seal in gas, but they may or may not use oil to lubricate the components. The size and speed of the pump


have a direct impact on processing speed, as well as actual process re- sults. A variety of other factors in- clude the size of the chamber, the distance of the pump from the cham- ber, the length and diameter of the hose connecting the pump and the chamber, the base processing pres- sure required, time required to reach the base pressure, process pressure and gas load during processing. As for the power generator, the


type and size of the substrate is a de- termining factor. If it is a conductive substrate, a DC, RF or milliwatt power supply can be used. Non-con- ductive materials require an RF or milliwatt power supply. The temperature requirements


for the processes conducted in the chamber will determine the required maximum substrate temperature for the system. Understanding the ther- mal budget of the substrates may ne- cessitate adding a temperature con- troller or chiller to the system. Another key factor is whether


the tool will be used for production or R&D. For production, will it be fully or semi-automated? For R&D, will it be semi-automated or manual?


Facility Requirements For production engineers, facility


considerations, such as the footprint of the system, types of connections re- quired and accessibility for mainte- nance are equally as important. So, too, are the ongoing consumable costs for electricity, gas, compressed air, reagents and chemicals involved. Pro- duction volumes factor heavily into this consideration as the cost-per-piece for thousands of parts is very different than that of millions.


The duty cycle of the equipment


can determine whether the most cost-effective vacuum pump option is wet or dry, for example. Estimating the number of hours each day the tool will be utilized is also important to calculate cost of ownership (COO). Most customers have a prede-


termined budget and delivery time- line. PVA TePla strives to under- stand these parameters up front to tailor a solution that meets each cus- tomer’s requirements. Taking budget constraints into account configures the plasma system to meet process requirements, while keeping options


open for future upgrades. Contact: PVA TePla America,


251 Corporate Terrace, Corona, CA 92879 % 951-371-2500 fax: 951-346-3232 E-mail: rayc@pvateplaamerica.com Web: www.pvateplaamerica.com r


May, 2018


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120