In order to make the most effective use of your thin film deposition system; it is necessary to understand some of the basic parameters involved in creating thin films using the plasma source. Plasma deposition systems typically consist of a parallel plate configuration where the upper electrode is RF and the lower electrode is ground. Gas comes through the showerhead. In such configuration activating two species with substantially different activation energy is difficult, and both stoichiometry and thickness can not be uniform over large substrate areas. Here the secondary gas input line allows difficult to activate species to enter plasma from the source and easier to activate species are provided at a through the primary line of the source. Then best uniformity can be achieved by optimizing flows at different pressures.
 
It is imperative that a deep base pressure be achieved in order to get the adhesion and cleanliness necessary for high quality thin film deposition.  The lowest RF power at which discharge can be initiated depends on the type of gas used; however typically these pressures are around 0.1 Torr. RF power can be increased when auto tuning is capable of real time tuning with reflected powers in the range of 1% of total. At high powers, the plasma may display instabilities, which may be removed by increasing pressure. At lower pressures more uniform and diffused plasma can be obtained at lower power levels. Typical operational pressure range is 0.1 to 1 Torr, 100-200W. Below is a graph of the operating power limits for the plasma source. Any values in the shaded region should produce consistent plasma.
 
 
Uniformity of the deposition would be function of the flow rates, substrate temperature and the spacing between the electrodes. The substrate can be heated to a maximum 400C.
 
Biasing the platen can control ion acceleration energy through the plasma sheet. Plasma potential can also be affected by controlling electron loss through the plasma. Therefore, through biasing and heating, denser and harder films can be produced.

Evaporation is a powerful technique for thick metal or organic coatings. It is a vapor phase deposition technique and requires good vacuum. High temperatures must be reached to vaporize the material under vacuum to coat the substrate. Typically any material where evaporation temperature is less than 2000 0C can be evaporated at about 10-5 Torr for coating. However, appropriate crucibles (Alumina, Quartz, Boron Nitride etc) with proper baskets or boats must be chosen. Organic materials require lower temperatures (about 6000C) but better controlled.
Some materials have low sticking coefficient making it difficult to build a film or require substrate heating (optional) to control stoichiometry. These problems can be overcome by pressure and heating control. Having a computer-controlled system we can assure low background pressure is reached before evaporation can start. Especially at the beginning, impurities that outgas can be pumped down by heating the empty crucible or the boat.

In order to make the most effective use of your thin film deposition system, it is necessary to understand some of the basic parameters involved in creating thin films. The deposition process can be broadly classified into physical vapor deposition ( PVD ) and chemical vapor deposition ( CVD ). In CVD , the film growth occurs at higher temperatures leading to the development of corrosive gaseous products and might leave impurities on the film. The PVD process can be performed at lower deposition temperatures also leaving corrosive products aside, but deposition rates are lower and it leaves residual compressive stress in the film. Electron beam physical vapor deposition, nevertheless, yields a high deposition rate from 0.1 μm / min to 10 μm / min at relatively low substrate temperatures, with very high material usage efficiency. Due to the very high deposition rate, this process has industrial applications for wear resistant and thermal barrier coatings in aerospace industries, hard coatings for cutting and tool industries, and electronic and optical films for semiconductor industries. In principle, solid evaporant such as powder, granules, lumps, or shaped plug, is placed in the source's copper hearth or in a hearth-liner. A high electron flux produced by hot filament positioned beneath the source is extracted and electro statically and magnetically bent/focused on the top of the evaporant. The electron beam's energy elevates the evaporant's surface temperature. Seldom is the beam rastered to increase the evaporation region. Since the evaporation region is enclosed by cooler (often solid) evaporant, unlike other thermal sources, the e-beam source's vapor plume is chiefly uncontaminated by crucible material. Production scale e-beam sources are usually single pocket (one hearth). Multipocket source (4 or 6 hearths) is available for R & D applications. A cover plate obscures the pockets "not-in-use" to prevent vapor cross talk. Multipocket sources are particularly convenient when depositing multilayer films on a single substrate.

揭秘遠(yuǎn)程微波PECVD系統(tǒng)

Nano-Master的遠(yuǎn)程微波等離子體化學(xué)氣相沉積（PECVD）系統(tǒng)應(yīng)用范圍廣泛，包含：

• 基片或粉體的等離子誘導(dǎo)表面改性

• 等離子清洗

• 粉體或顆粒表面等離子聚合

• SiO2,Si3N4或DLC及其他薄膜

• CNT和石墨烯的選擇性生長

• 單晶或多晶金剛石生長

微波模塊：NANO-MASTER獨(dú)J專利技術(shù)的高質(zhì)量長壽命遠(yuǎn)程微波源，頻率為2.45GH，微波發(fā)射功率可以自主調(diào)節(jié)，微波反射功率可通過調(diào)節(jié)降低至發(fā)射功率的千分之一以內(nèi)。遠(yuǎn)程微波源，可實(shí)現(xiàn)無損傷缺陷的沉積或生長。

設(shè)備腔體：水冷側(cè)壁，確保在高溫工藝下腔體外表面溫度控制在60℃內(nèi)；在高溫工藝進(jìn)行過程中，等離子體被束縛在有限的體積內(nèi)，不會(huì)對(duì)腔體造成刻蝕。

樣品臺(tái)：可自動(dòng)加熱到最高1200℃，PID精確控制，精度±1℃，跟微波電源的加熱獨(dú)立。高溫工藝下可持續(xù)旋轉(zhuǎn)，主動(dòng)冷卻。具有自動(dòng)升降功能，可針對(duì)自動(dòng)Load Unload下降樣品臺(tái)便于片托自動(dòng)取出。

溫度模塊：通過系統(tǒng)參數(shù)實(shí)現(xiàn)襯底溫度精確控制,在穩(wěn)定的工藝過程中溫度浮動(dòng)不超過±10℃。利用雙波長高溫計(jì)實(shí)現(xiàn)對(duì)襯底的非接觸式溫度測量；樣品臺(tái)內(nèi)部通過熱電偶測量。

氣體控制：根據(jù)需求最多可配置8路工藝氣體，配備吹掃氣路，利用氮?dú)饣蚴菤鍤鈱?duì)管路吹掃。淋浴頭和氣體環(huán)均勻設(shè)計(jì)，使得氣體在高溫工作狀態(tài)下成分均一，流速穩(wěn)定，不會(huì)對(duì)襯底造成擾動(dòng)。

真空模塊：腔室的極限真空度可達(dá)1*10-5Pa

樣品傳送模塊：系統(tǒng)可以支持自動(dòng)Load Lock實(shí)現(xiàn)計(jì)算機(jī)控制的自動(dòng)進(jìn)樣和出片

控制模塊：配備計(jì)算機(jī)控制系統(tǒng)，詳細(xì)記錄工藝過程中各項(xiàng)參數(shù)。具備安全互鎖功能及4級(jí)密碼授權(quán)訪問控制。

                 金剛石膜                          較大微晶金剛石膜                        精細(xì)紋理納米結(jié)晶金剛石膜

                                                             SEM圖像                                            SEM圖像

以遠(yuǎn)程微波PECVD系統(tǒng)沉積金剛石薄膜為例，從甲烷、氫氣或氬氣的氣體混合物中將多晶金剛石薄膜沉積到襯底上。沉積過程中的基片溫度通常為800~900°C，通過雙波長高溫計(jì)測量。甲烷、氫氣和氬氣的濃度、功率和壓力值可以改變，以產(chǎn)生各種金剛石膜紋理。因金剛石的許多特性：如化學(xué)惰性和穩(wěn)定性，高導(dǎo)熱性，高聲速，高斷裂強(qiáng)度，疏水性，耐磨性，生物惰性，其表面可功能化，并涂覆保形性等，使其成為許多應(yīng)用的獨(dú)特選擇。應(yīng)用包括MEMS/NEMS器件、摩擦學(xué)（機(jī)械和生物部件涂層）、熱（散熱器/擴(kuò)散器）、切割工具、輻射傳感器（電離輻射探測器/劑量計(jì)）、電化學(xué)應(yīng)用（生化傳感器）、光學(xué)（紅外窗口、透鏡、X射線窗口）和離子束剝離箔。

NANO-MASTER的微波PECVD系統(tǒng)產(chǎn)品應(yīng)用于中科院深圳先進(jìn)技術(shù)研究院，該系統(tǒng)即將配套遠(yuǎn)程微波等離子源，帶直流偏壓，支持高達(dá)900度的樣品臺(tái)加熱，提供精確的控溫，該系統(tǒng)可以支持石墨烯和CNT碳納米管陣列。
 
根據(jù)客戶要求，配套的遠(yuǎn)程微波源將真正實(shí)現(xiàn)對(duì)所沉積薄膜的無損傷。高溫可以支持碳類薄膜的應(yīng)用，在等離子作用下，實(shí)際的應(yīng)用溫度將得以大大降低。系統(tǒng)將采用計(jì)算機(jī)全自動(dòng)的工藝控制，配套的軟件將方便用戶實(shí)現(xiàn)高重復(fù)性地沉積應(yīng)用。該系統(tǒng)所采用的緊湊設(shè)計(jì)，將大大節(jié)省實(shí)驗(yàn)室的空間，并可以支持百級(jí)的超凈間使用。

近日，NANO-MASTER工程師至浙江中寧硅業(yè)有限公司，順利安裝驗(yàn)收NPE-3500型PECVD等離子體化學(xué)氣相沉積設(shè)備！

NANO-MASTER的PECVD系統(tǒng)能夠沉積高質(zhì)量的SiO2、Si3N4、CNT、DLC和SiC等薄膜?？蓱?yīng)用于等離子誘導(dǎo)表面改性、等離子清洗、等離子聚合等。根據(jù)不同應(yīng)用，可選用RF、HCP、ICP或MW微波等多種規(guī)格的離子源。標(biāo)準(zhǔn)樣品臺(tái)尺寸有6”和8”可選，最高可定制到16”或者其他更大的尺寸，樣品臺(tái)可提供RF、Pulse DC或DC偏壓。樣品臺(tái)可提供電阻加熱或紅外燈加熱。

系統(tǒng)標(biāo)配渦輪分子泵和機(jī)械泵，極限真空到5*10-7Torr，腔體壓力調(diào)節(jié)通過PC自動(dòng)控制渦輪速度而全自動(dòng)調(diào)節(jié)，快速穩(wěn)定。

工藝過程通過觸摸監(jiān)控屏幕和Labview軟件，可實(shí)現(xiàn)全自動(dòng)的PC控制，具有高度的可重復(fù)性。系統(tǒng)具有完整的安全聯(lián)鎖，提供四級(jí)密碼授權(quán)訪問保護(hù)。能直接研發(fā)和量產(chǎn)應(yīng)用。

NANO-MASTER的PECVD等離子體化學(xué)氣相沉積選配項(xiàng)

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