JP2002346915A - Chemical mechanical polishing method for diamond thin film - Google Patents
Chemical mechanical polishing method for diamond thin filmInfo
- Publication number
- JP2002346915A JP2002346915A JP2001153758A JP2001153758A JP2002346915A JP 2002346915 A JP2002346915 A JP 2002346915A JP 2001153758 A JP2001153758 A JP 2001153758A JP 2001153758 A JP2001153758 A JP 2001153758A JP 2002346915 A JP2002346915 A JP 2002346915A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- diamond thin
- polishing
- diamond
- abrasive grains
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、気相合成法（ＣＶＤ）
で成膜されたダイヤモンド薄膜を研磨して極めて平滑で
損傷のない表面に調質する化学機械研磨方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor phase synthesis method (CVD).
The present invention relates to a chemical-mechanical polishing method for polishing a diamond thin film formed by the method described above to form a very smooth and undamaged surface.
【０００２】[0002]
【従来の技術】ダイヤモンドは、バンドギャップ，熱伝
導率，電子及び正孔の移動度，絶縁破壊電圧等において
シリコンよりも優れた半導体特性を呈する。たとえば、
シリコンのバンドギャップ1.13eVに対し、ダイヤモンド
のバンドギャップは5.5eVと大きいことから、高温雰囲
気での使用が可能な電子デバイスが得られる。熱伝導率
もシリコンの1.5W／cm・Kに比較して20.5W／cm・Kと格段
に大きく、素子で発生したジュール熱が容易に放出され
る優れた放熱特性を呈する。また、シリコンの電子移動
度1500cm2／V・秒，正孔移動度600 cm2／V・秒に対してダ
イヤモンドの電子移動度1800 cm2／V・秒，正孔移動度16
00 cm2／V・秒と移動度が大きく、高速作動に適した半導
体材料である。更には、絶縁破壊電圧がシリコンの3×1
05V／cmに対し100×105V／cmと大きなことから、素子間
隔を狭くした高密度設計にあってもリーク電流が発生し
ない。2. Description of the Related Art Diamond exhibits superior semiconductor characteristics to silicon in terms of band gap, thermal conductivity, mobility of electrons and holes, breakdown voltage, and the like. For example,
Since the band gap of diamond is as large as 5.5 eV as compared with the band gap of silicon of 1.13 eV, an electronic device that can be used in a high-temperature atmosphere can be obtained. The thermal conductivity is 20.5 W / cm · K, which is much higher than the 1.5 W / cm · K of silicon, and exhibits excellent heat dissipation characteristics that easily release Joule heat generated in the device. The electron mobility of silicon 1500 cm 2 / V · sec, the electron mobility of the diamond to the hole mobility 600 cm 2 / V · sec 1800 cm 2 / V · sec, hole mobility 16
It has a high mobility of 00 cm 2 / V · sec and is a semiconductor material suitable for high-speed operation. Furthermore, the breakdown voltage is 3 × 1 of silicon.
Since it is as large as 100 × 10 5 V / cm with respect to 0 5 V / cm, no leak current occurs even in a high-density design in which the element interval is narrowed.
【０００３】ダイヤモンドは、このような優れた半導体
特性から、高温雰囲気で使用しても故障や誤動作がなく
高密度設計及び高速可動が可能な電子デバイス用途に適
している。更に、パワートランジスタを作製する際、小
型・薄型構造にしてドーパント濃度を高くしても、絶縁
破壊が起こらず、電力損失が桁違いに小さな特性が得ら
れる。ダイヤモンドには天然ダイヤモンド，高圧合成法
や気相合成法で製造された人工ダイヤモンド等がある
が、気相合成法で製造したダイヤモンド薄膜が半導体用
途に適している。常温・常圧における炭素の平衡相はグ
ラファイトであるので、ダイヤモンド薄膜の作製に際し
ては、気相合成による非平衡の化学反応が利用される。
半導体材料としては単結晶のダイヤモンド薄膜が最も好
ましいが、気相合成反応の通常条件下では基材の随所に
ダイヤモンド核が発生・成長するため多結晶薄膜とな
る。得られたダイヤモンド薄膜は、結晶間の粒界強度が
弱く、粗い表面を呈する。[0003] Due to such excellent semiconductor properties, diamond is suitable for electronic device applications that can be designed with high density and operate at high speed without failure or malfunction even when used in a high-temperature atmosphere. Furthermore, when a power transistor is manufactured, even if the dopant concentration is increased by using a small and thin structure, dielectric breakdown does not occur and power loss can be reduced by orders of magnitude. Diamond includes natural diamond, artificial diamond produced by a high-pressure synthesis method or a vapor phase synthesis method, and a diamond thin film produced by a vapor phase synthesis method is suitable for semiconductor applications. Since the equilibrium phase of carbon at normal temperature and normal pressure is graphite, a non-equilibrium chemical reaction by vapor phase synthesis is used in producing a diamond thin film.
As a semiconductor material, a single-crystal diamond thin film is most preferable. However, under normal conditions of a gas phase synthesis reaction, diamond nuclei are generated and grown everywhere on a substrate, so that a polycrystalline thin film is formed. The obtained diamond thin film has a weak grain boundary strength between crystals and exhibits a rough surface.
【０００４】ダイヤモンド薄膜を用いて電子デバイスを
作製する際、代表的な方法としてリソグラフィーが採用
されているが、微細構造の素子をダイヤモンド薄膜上に
作りこむためにはダイヤモンド薄膜が平坦な表面をもつ
ことが必要である。電子デバイスの超微細化が一段と強
くなっている傾向に伴い、基板表面に欠陥がないこと及
び基板の平坦度に関してもナノメータオーダーの平坦度
が要求されるようになってきている。表面研磨には砥粒
を用いた機械研磨が通常採用されるが、機械研磨をダイ
ヤモンド薄膜に適用すると、砥粒の摺擦に起因する機械
的作用（微小切削）によって硬くて脆いダイヤモンドが
結晶粒内で破砕され、或いは粒界強度の弱い結晶粒間で
脱粒し、薄膜表面を却って粗面化する虞がある。また、
研磨対象が硬質のダイヤモンドであることから、大きな
加工圧が必要とされ、長時間の加工，加工コストの上昇
等、種々の問題が派生する。When an electronic device is manufactured using a diamond thin film, lithography is employed as a typical method. In order to form an element having a fine structure on the diamond thin film, the diamond thin film must have a flat surface. is necessary. With the trend toward ever-increasing ultrafineness of electronic devices, it has been required that the substrate surface be free from defects and that the flatness of the substrate be on the order of nanometers. Mechanical polishing using abrasive grains is usually used for surface polishing. However, when mechanical polishing is applied to a diamond thin film, hard and brittle diamond is formed by the mechanical action (small cutting) caused by rubbing of the abrasive grains. There is a possibility that the thin film surface may be crushed or fall between crystal grains having low grain boundary strength, and the thin film surface may be roughened. Also,
Since the object to be polished is a hard diamond, a large processing pressure is required, which causes various problems such as long-time processing and an increase in processing cost.
【０００５】そこで、化学的作用によってダイヤモンド
薄膜を研磨する方法が検討されている。たとえば、ダイ
ヤモンドとFeが高温で反応することを利用し、鉄製円盤
を研磨工具に用い、730℃以上の水素ガス雰囲気でダイ
ヤモンド薄膜を研磨する方法（楊政峰，吉川昌範：New
Diamond, 11(1988), 18)が知られている。この方法で
は、720℃程度にまで昇温したFeにダイヤモンド薄膜を
接触させることにより、ダイヤモンドとFeとの反応でセ
メンタイトFe3Cを生成させている。炭化ケイ素円盤上に
SiOx膜をプラズマ蒸着すると同時にSiOx膜の上にダイヤ
モンド薄膜を擦過させる方法（日経メカニカル7月23日
号(1990)，66）も知られている。この場合、SiOx膜中の
酸素とダイヤモンドが反応し、COやCO2としてダイヤモ
ンドが除去されることにより研磨が進行すると考えられ
ている。Therefore, a method of polishing a diamond thin film by a chemical action has been studied. For example, a method of polishing diamond thin films in a hydrogen gas atmosphere of 730 ° C or higher using an iron disk as a polishing tool, taking advantage of the fact that diamond and Fe react at high temperatures (Yang Masamine, Yoshinori Yoshikawa: New
Diamond, 11 (1988), 18) is known. In this method, cementite Fe 3 C is generated by a reaction between diamond and Fe by bringing a diamond thin film into contact with Fe heated to about 720 ° C. On silicon carbide disk
A method of rubbing the diamond thin film on top of the SiO x film SiO x film at the same time as plasma vapor deposition (Nikkei Mechanical July 23 issue (1990), 66) are also known. In this case, it is considered that the polishing proceeds by reacting the oxygen in the SiO x film with the diamond and removing the diamond as CO or CO 2 .
【０００６】[0006]
【発明が解決しようとする課題】化学研磨では、ダイヤ
モンドと砥粒，研磨液，雰囲気ガスの化学反応を利用し
てダイヤモンド薄膜の表面を平滑化する方法であり、機
械研磨のように砥粒がダイヤモンド薄膜に摺擦すること
による脱粒や歪導入がない。そのため、化学研磨された
ダイヤモンド薄膜の表面は、無歪で平坦度の高い表面に
効率よく改質される。しかし、ダイヤモンドは、常温で
極めて安定な物質であり、通常のアルカリ，酸，腐食性
ガス等とほとんど反応せず、勿論固体材料とも反応しな
い。そのため、ダイヤモンド薄膜の研磨に高温雰囲気や
特殊反応が必要とされ、それに応じた特殊装置を用いた
研磨工程となることからコスト上昇の原因となる。ま
た、真空雰囲気内での研磨になることから、作業工程自
体も複雑化する。The chemical polishing is a method of smoothing the surface of a diamond thin film using a chemical reaction between diamond and abrasive grains, a polishing solution, and an atmospheric gas. There is no degranulation or distortion introduced by rubbing the diamond thin film. Therefore, the surface of the diamond thin film that has been chemically polished is efficiently modified into a surface having no distortion and a high flatness. However, diamond is a substance that is extremely stable at room temperature, hardly reacts with ordinary alkalis, acids, corrosive gases, and the like, and of course does not react with solid materials. Therefore, a high-temperature atmosphere or a special reaction is required for polishing the diamond thin film, and a polishing process using a special device corresponding to the high-temperature atmosphere or a special reaction causes a cost increase. In addition, since the polishing is performed in a vacuum atmosphere, the operation process itself is complicated.
【０００７】[0007]
【課題を解決するための手段】本発明は、このような問
題を解消すべく案出されたものであり、化学反応及び砥
粒による機械的作用が複合された化学機械研磨によって
ダイヤモンド薄膜を研磨することにより、欠陥がなくナ
ノメータオーダーで平滑な表面にダイヤモンド薄膜を改
質することを目的とする。SUMMARY OF THE INVENTION The present invention has been devised to solve such a problem, and a diamond thin film is polished by chemical mechanical polishing in which chemical reaction and mechanical action by abrasive grains are combined. By doing so, it is an object to modify the diamond thin film to have a smooth surface with no defects and on the order of nanometers.
【０００８】本発明の化学機械研磨は、その目的を達成
するため、酸化触媒作用のある砥粒を分散させた酸化性
研磨液にダイヤモンド薄膜を浸漬し、砥粒で薄膜表面を
擦過しながらダイヤモンド薄膜を研磨することを特徴と
する。砥粒としてはたとえば酸化クロム及び／又は酸化
鉄が使用され、過酸化水素水，硝酸塩水溶液，又はそれ
らの混合液に砥粒を分散させた研磨液を調製することが
好ましい。In the chemical mechanical polishing of the present invention, in order to achieve the object, a diamond thin film is immersed in an oxidizing polishing liquid in which abrasive grains having an oxidation catalytic action are dispersed, and the diamond thin film is rubbed with the abrasive grains. The method is characterized by polishing a thin film. As the abrasive grains, for example, chromium oxide and / or iron oxide are used, and it is preferable to prepare a polishing liquid in which the abrasive grains are dispersed in a hydrogen peroxide solution, a nitrate aqueous solution, or a mixture thereof.
【０００９】[0009]
【作用】化学機械研磨では、加工液又は加工雰囲気の気
体が加工物の表面と化学反応し、反応生成物の皮膜とな
って加工物の表面が覆われることがある。化学的研磨作
用だけでは加工物表面が反応生成物で被覆されることに
より反応が停止するが、加工物表面を擦過する砥粒の存
在下で研磨が進行する化学機械研磨においては、反応生
成物の皮膜が砥粒の擦過によって加工物表面から引き剥
がされ、下地表面が新たに露出する。新たに露出した下
地表面は加工液又は加工雰囲気の気体と化学反応して反
応生成物の皮膜で再度覆われる。反応生成物の皮膜生成
及び皮膜剥離が繰り返されるため、化学反応が停止する
ことなく高度に平坦化された表面に改質される。このよ
うな砥粒の作用は、コロイダルシリカ砥粒を分散させた
アルカリ溶液中でシリコンを湿式研磨するときに確認さ
れている。In the chemical mechanical polishing, the processing liquid or the gas in the processing atmosphere chemically reacts with the surface of the workpiece, and sometimes forms a film of a reaction product, thereby covering the surface of the workpiece. The reaction stops when the surface of the workpiece is covered with the reaction product by chemical polishing alone, but in chemical mechanical polishing where polishing proceeds in the presence of abrasive grains rubbing the surface of the workpiece, the reaction product Is peeled off from the surface of the workpiece by rubbing of the abrasive grains, and the underlying surface is newly exposed. The newly exposed underlayer surface reacts chemically with the processing liquid or gas in the processing atmosphere and is again covered with a film of the reaction product. Since the film formation and film peeling of the reaction product are repeated, the surface is modified into a highly planarized surface without stopping the chemical reaction. The effect of such abrasive grains has been confirmed when wet polishing silicon in an alkaline solution in which colloidal silica abrasive grains are dispersed.
【００１０】一方、加工部に存在する砥粒が加工物と直
接的に反応し、或いは砥粒の触媒作用により加工液と被
加工物の研磨反応が促進される場合がある。すなわち、
単に砥粒が加工物表面に接触するだけでは研磨に有効な
化学反応は生じないが、加工物表面を砥粒が擦過する際
の機械的作用によって加工物表面の局部に高密度のエネ
ルギーが伝達される。高密度エネルギーの伝達によって
砥粒と接触した加工物表面が活性化され、砥粒，加工液
又は加工雰囲気の気体に対する反応性が向上する。たと
えば、酸化クロムを砥粒に用いてSiCを乾式研磨すると
き、研磨領域にある砥粒表面に過剰の酸素が保持され、
砥粒擦過時に酸素が加工物表面に押し付けられることに
よりSiC＋O2→非晶質SiOx＋非晶質C又はSiC+O2→非晶質
Si−C−Oの化学反応が誘起されると考えられる。On the other hand, there are cases where the abrasive grains present in the processing portion react directly with the workpiece, or the polishing reaction between the working fluid and the workpiece is accelerated by the catalytic action of the abrasive grains. That is,
Simply contacting the abrasive grains with the workpiece surface does not produce a chemical reaction that is effective for polishing, but high-density energy is transmitted locally to the workpiece surface by the mechanical action of the abrasive grains rubbing the workpiece surface Is done. The surface of the workpiece in contact with the abrasive grains is activated by the transmission of the high-density energy, and the reactivity to the abrasive grains, the machining liquid, or the gas in the machining atmosphere is improved. For example, when dry polishing SiC using chromium oxide as abrasive grains, excess oxygen is retained on the abrasive grain surface in the polishing area,
When oxygen is pressed against the workpiece surface during abrasive grain rubbing, SiC + O 2 → Amorphous SiO x + Amorphous C or SiC + O 2 → Amorphous
It is considered that a chemical reaction of Si-CO is induced.
【００１１】酸化クロムを砥粒に用いたSiCの乾式研磨
では、研磨に有効な化学反応はSiの酸化であり、結果と
して余剰のCが非晶質固体になり、或いは反応生成物SiO
2に取り込まれることもあるが、加工後の表面に残存す
ることが懸念される。構造材料としての用途では反応生
成物が多少付着していても以後の工程や製品の特性に悪
影響を及ぼさないが、電子デバイス用途では不純物が微
量でも残存すると以降の素子形成工程及び得られる素子
の特性に重大な影響を及ぼす。他方，本発明では、Cの
直接酸化を利用してダイヤモンド薄膜を研磨している。
Cの直接酸化は、C+O2→CO又はCO2に従ったガス化反応で
あり、加工後の表面に余剰C等を残存させることがな
い。Cの直接酸化は、酸化作用のある研磨液を使用する
ことによって促進される（図１）。In dry polishing of SiC using chromium oxide as abrasive grains, a chemical reaction effective for polishing is oxidation of Si, and as a result, excess C becomes an amorphous solid or the reaction product SiO
2 , but may remain on the surface after processing. In the application as a structural material, even if reaction products are slightly attached, it does not adversely affect the characteristics of subsequent processes and products. Significant effects on properties. On the other hand, in the present invention, the diamond thin film is polished using the direct oxidation of C.
Direct oxidation of C is a gasification reaction in accordance with C + O 2 → CO or CO 2 , and does not leave excess C or the like on the processed surface. Direct oxidation of C is promoted by using an oxidizing polishing liquid (FIG. 1).
【００１２】酸素が存在する系で炭素は熱力学的に不安
定であるが、室温雰囲気に放置されたダイヤモンド又は
黒鉛が重量減少しないことにみられるように、炭素のガ
ス化反応は極めて遅い。室温付近の温度に維持されてい
る溶液中に浸漬されているダイヤモンドや黒鉛も、酸化
剤の有無による重量減少の差異が生じない。この点、本
発明にあっては、砥粒を分散させた酸化性の研磨液を用
いてダイヤモンド薄膜を湿式研磨している。研磨液は、
酸化触媒作用をもつ粉状物質を砥粒として酸化作用のあ
る溶液に分散させることにより調製される。酸化作用の
ある溶液には、過酸化水素水（H2O2），硝酸塩（MxN
O3）水溶液等が掲げられる。酸化触媒作用のある砥粒に
は、酸化クロム（Cr2O3），酸化鉄（Fe2O3）等が掲げら
れる。砥粒は、化学研磨及び機械研磨を効率よく進行さ
せる上で10〜100ｇ／ｌの割合で分散させることが好ま
しい。Although carbon is thermodynamically unstable in a system where oxygen is present, the gasification reaction of carbon is extremely slow, as seen by the fact that diamond or graphite left in a room temperature atmosphere does not lose weight. Even for diamond and graphite immersed in a solution maintained at a temperature near room temperature, there is no difference in weight loss due to the presence or absence of the oxidizing agent. In this regard, in the present invention, the diamond thin film is wet-polished using an oxidizing polishing liquid in which abrasive grains are dispersed. The polishing liquid is
It is prepared by dispersing a powdery substance having an oxidation catalytic action as an abrasive in a solution having an oxidizing action. Hydrogen peroxide (H 2 O 2 ), nitrate (M x N)
O 3 ) Aqueous solution and the like are listed. Chromium oxide (Cr 2 O 3 ), iron oxide (Fe 2 O 3 ), and the like are listed as abrasive grains having an oxidation catalytic action. The abrasive grains are preferably dispersed at a rate of 10 to 100 g / l in order to efficiently advance chemical polishing and mechanical polishing.
【００１３】研磨液に溶存する酸素が酸化触媒作用のあ
る砥粒の表面に吸着され、反応性に富む状態が維持され
る。そのため、ダイヤモンド薄膜の表面を擦過すると、
機械的作用と相俟ってC＋O2→CO又はCO2に従った直接酸
化反応が進行する。このとき、酸化作用のある溶液中で
砥粒表面に保持される酸素の量が多くなっているので、
該直接酸化反応が促進される。しかも、常温雰囲気での
研磨であるため、従来法のように特殊雰囲気を必要とせ
ず、研磨作業自体も容易になる。[0013] Oxygen dissolved in the polishing liquid is adsorbed on the surface of the abrasive grains having an oxidation catalytic action, and a state of high reactivity is maintained. Therefore, when the surface of the diamond thin film is rubbed,
The direct oxidation reaction according to C + O 2 → CO or CO 2 proceeds in combination with the mechanical action. At this time, since the amount of oxygen retained on the surface of the abrasive grains in the oxidizing solution is large,
The direct oxidation reaction is promoted. Moreover, since the polishing is performed in a normal temperature atmosphere, a special atmosphere is not required unlike the conventional method, and the polishing operation itself is facilitated.
【００１４】化学的作用及び機械的作用が複合されてダ
イヤモンド薄膜に及ぼされるため、仮にダイヤモンドが
化学的にエッチングされる場合があっても薄膜全面が除
去され、研磨されたダイヤモンド薄膜の表面は、ナノメ
ータオーダーで平滑な表面に改質される。そのため、リ
ソグラフィ法で電子デバイスを作りこむ際、精度良く且
つ高い歩留で非常に微細な素子を作製できる。また、一
枚の基板から多数のチップを取る際にも、高度に平滑な
平面であることから要求特性を満足するチップの生産性
が向上する。Since the chemical action and the mechanical action are combined to affect the diamond thin film, even if diamond is chemically etched, the entire thin film is removed, and the polished surface of the diamond thin film is Modified to a smooth surface on the order of nanometers. Therefore, when an electronic device is manufactured by a lithography method, an extremely fine element can be manufactured with high accuracy and high yield. Further, even when a large number of chips are obtained from one substrate, the productivity of chips satisfying the required characteristics is improved because of the highly smooth flat surface.
【００１５】また、半導体用基材には平滑度，面粗さ等
の幾何学的精度の外に加工面品位も要求されるが、化学
反応の誘起手段として機械的作用を利用し、実質的には
化学的作用でダイヤモンド薄膜を研磨する化学機械研磨
によるとき、砥粒の擦過に起因したクラック，歪等の欠
陥が研磨表面に導入されることもない。したがって、半
導体特性に重大な影響を与える表面欠陥がなく、高品質
の電子デバイス作製用基板として使用される。Although a semiconductor substrate is required to have a processed surface quality in addition to geometrical accuracy such as smoothness and surface roughness, it is necessary to use a mechanical action as a means for inducing a chemical reaction. In the case of chemical mechanical polishing in which a diamond thin film is polished by a chemical action, defects such as cracks and distortions caused by abrasive grains are not introduced into the polished surface. Therefore, it is used as a high-quality substrate for manufacturing electronic devices without surface defects that have a significant effect on semiconductor characteristics.
【００１６】[0016]
【実施例】Si（001）基板上にCVD法で作製した膜厚0.1m
mのダイヤモンド薄膜を化学機械研磨することに本発明
を適用した。研磨液は、34.5％過酸化水素水50mlに粒径
1.6μmの酸化クロム5gを分散することによって調製し
た。フッ素樹脂製の容器に収容した研磨液（室温）にダ
イヤモンド薄膜を浸漬し、ダイヤモンド薄膜に対向する
側にガラス板を貼り付けた攪拌子を加工圧27kPaでダイ
ヤモンド薄膜に押し付け、周速度3.2m／秒で回転させ
た。[Example] A film thickness of 0.1 m formed on a Si (001) substrate by a CVD method.
The present invention was applied to chemical mechanical polishing of a diamond thin film of m. The polishing liquid has a particle size of 50 ml of 34.5% hydrogen peroxide solution.
It was prepared by dispersing 5 g of 1.6 μm chromium oxide. The diamond thin film is immersed in a polishing liquid (room temperature) contained in a container made of fluororesin, and a stirrer with a glass plate attached to the side facing the diamond thin film is pressed against the diamond thin film at a processing pressure of 27 kPa, and a peripheral speed of 3.2 m / Rotated in seconds.
【００１７】43.5時間経過した時点で攪拌子の回転を止
め、研磨液からダイヤモンド薄膜を引き上げた。このダ
イヤモンド薄膜の表面を光学顕微鏡で観察したところ、
鏡面研磨された部分が左側周辺（図２）に検出され、そ
の他の表面が未研磨状態であった。研磨面の平坦度を詳
細に調査するため、研磨面表面をSEM観察した。図3のSE
M像にみられるように、中央の研磨途中の領域の左側は
平坦であった。更に研磨された部分を20000倍の高倍率
で観察しても、スクラッチ等の表面凹凸を意味するコン
トラストが検出されなかった。この観察結果から、研磨
された表面は、表面粗さがRmax 30nm以下のナノメータ
オーダーで平滑な表面であることが判った。When 43.5 hours had passed, the rotation of the stirrer was stopped, and the diamond thin film was pulled up from the polishing solution. When the surface of this diamond thin film was observed with an optical microscope,
A mirror-polished portion was detected around the left side (FIG. 2), and the other surfaces were unpolished. In order to investigate the flatness of the polished surface in detail, the polished surface was observed by SEM. SE in Fig. 3
As can be seen in the M image, the left side of the central area during polishing was flat. Further, even when the polished portion was observed at a high magnification of 20000 times, no contrast meaning surface irregularities such as scratches was detected. From this observation result, it was found that the polished surface was a smooth surface having a surface roughness of Rmax 30 nm or less on the order of nanometers.
【００１８】また、過酸化水素水に代え純水に酸化クロ
ムを分散させた研磨液を用いて同様な条件下でダイヤモ
ンド薄膜を化学機械研磨した。研磨開始から72時間経過
した時点でダイヤモンド薄膜の表面を観察したところ、
ダイヤモンド薄膜の表面一部が鏡面研磨されていた（図
４）。この場合に鏡面研磨された部分は、同程度の平滑
度を示すものの、過酸化水素に酸化クロムを分散させた
研磨液を使用した場合に比較して表面積が極端に小さく
なっており、過酸化水素が研磨反応（Cの直接酸化）に
有効に寄与していることが確認された。A diamond thin film was chemically and mechanically polished under the same conditions using a polishing liquid in which chromium oxide was dispersed in pure water instead of the hydrogen peroxide solution. When the surface of the diamond thin film was observed 72 hours after the start of polishing,
A part of the surface of the diamond thin film was mirror-polished (FIG. 4). In this case, although the mirror-polished portion shows the same degree of smoothness, the surface area is extremely small as compared with the case where a polishing solution in which chromium oxide is dispersed in hydrogen peroxide is used. It was confirmed that hydrogen effectively contributed to the polishing reaction (direct oxidation of C).
【００１９】比較のため、粒径1μmのダイヤモンド粒を
懸濁させたダイヤモンドスラリーを使用し、同一条件下
でダイヤモンド薄膜を機械研磨した。研磨開始から72時
間経過した時点でダイヤモンド薄膜の表面をSEM観察し
たところ、磨かれた痕跡が全く検出されず、却って粒内
割れや脱粒に起因する粗面化がみられた。For comparison, a diamond thin film in which diamond particles having a particle diameter of 1 μm were suspended was used, and a diamond thin film was mechanically polished under the same conditions. When the surface of the diamond thin film was observed by SEM 72 hours after the start of polishing, no trace of the polishing was detected at all, and rather, roughening due to intragranular cracking or shedding was observed.
【００２０】[0020]
【発明の効果】以上に説明したように、本発明において
は、C+O2→CO又はCO2の直接酸化反応が進行するように
酸化作用のある研磨液を用いてダイヤモンド薄膜を化学
機械研磨している。そのため、硬質で研磨困難な材料で
あったダイヤモンド薄膜の表面を平滑に改質でき、SiC
の化学機械研磨で生じたような余剰Cが薄膜表面に残留
することもない。このようにして表面改質されたダイヤ
モンド薄膜は、ナノメータオーダーで平滑な表面である
こと及びダイヤモンド本来の優れた半導体特性を活用
し、高出力の電子デバイスを高密度配置した基板等、高
密度化・高性能化が急速に進んでいる電子デバイスに好
適な基板として使用される。As described above, in the present invention, a diamond thin film is chemically and mechanically polished using a polishing liquid having an oxidizing effect so that a direct oxidation reaction of C + O 2 → CO or CO 2 proceeds. are doing. As a result, the surface of the diamond thin film, which was hard and difficult to polish,
Excess C, which is generated by chemical mechanical polishing, does not remain on the surface of the thin film. The diamond thin film surface-modified in this way has a smooth surface in the order of nanometers and utilizes the excellent semiconductor characteristics inherent in diamond, and has a higher density, such as a substrate on which high-power electronic devices are densely arranged. -It is used as a substrate suitable for electronic devices whose performance is rapidly increasing.
【図１】 過酸化水素水に酸化クロム砥粒を分散させた
酸化性研磨液を用いた化学機械研磨によりダイヤモンド
薄膜が研磨されることを説明するモデル図FIG. 1 is a model diagram illustrating that a diamond thin film is polished by chemical mechanical polishing using an oxidizing polishing liquid in which chromium oxide abrasive grains are dispersed in a hydrogen peroxide solution.
【図２】 本発明に従った化学機械研磨を43.5時間施し
たダイヤモンド薄膜の表面一部が研磨されていることを
示す写真FIG. 2 is a photograph showing that a part of the surface of a diamond thin film subjected to chemical mechanical polishing according to the present invention for 43.5 hours is polished.
【図３】 同研磨表面のSEM像Fig. 3 SEM image of the polished surface
【図４】 純水に酸化クロム砥粒を分散させた研磨液を
用いて化学機械研磨したダイヤモンド薄膜の表面を示す
SEM像FIG. 4 shows the surface of a diamond thin film chemically and mechanically polished using a polishing liquid in which chromium oxide abrasive grains are dispersed in pure water.
SEM image
Claims (3)
化性研磨液にダイヤモンド薄膜を浸漬し、砥粒で薄膜表
面を擦過しながらダイヤモンド薄膜を研磨することを特
徴とするダイヤモンド薄膜の化学機械研磨方法。A diamond thin film is characterized in that a diamond thin film is immersed in an oxidizing polishing liquid in which abrasive grains having an oxidation catalytic action are dispersed, and the diamond thin film is polished while rubbing the thin film surface with the abrasive grains. Mechanical polishing method.
粒として使用する請求項１記載の化学機械研磨方法。2. The chemical mechanical polishing method according to claim 1, wherein one or two of chromium oxide and iron oxide are used as abrasive grains.
の混合液に砥粒を分散させた研磨液を使用する請求項１
記載の化学機械研磨方法。3. A polishing liquid in which abrasive grains are dispersed in an aqueous solution of hydrogen peroxide, an aqueous solution of nitrate or a mixture thereof.
The chemical mechanical polishing method as described in the above.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001153758A JP3734722B2 (en) | 2001-05-23 | 2001-05-23 | Chemical mechanical polishing method for diamond thin film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001153758A JP3734722B2 (en) | 2001-05-23 | 2001-05-23 | Chemical mechanical polishing method for diamond thin film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2002346915A true JP2002346915A (en) | 2002-12-04 |
| JP3734722B2 JP3734722B2 (en) | 2006-01-11 |
Family
ID=18998223
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001153758A Expired - Fee Related JP3734722B2 (en) | 2001-05-23 | 2001-05-23 | Chemical mechanical polishing method for diamond thin film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3734722B2 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1318156C (en) * | 2004-12-23 | 2007-05-30 | 彭彤 | Manufacturing method of diamond wire drawing mould |
| JP2008136983A (en) * | 2006-12-05 | 2008-06-19 | Osaka Univ | Catalyst-aided chemical processing method and apparatus |
| EP1894900A3 (en) * | 2006-08-28 | 2010-02-24 | Osaka University | Catalyst-aided chemical processing method and apparatus |
| US7776228B2 (en) | 2006-04-11 | 2010-08-17 | Ebara Corporation | Catalyst-aided chemical processing method |
| JP2010188487A (en) * | 2009-02-19 | 2010-09-02 | Kumamoto Univ | Catalyst support type chemical machining method, and machining apparatus using the same |
| CN102011106A (en) * | 2010-09-07 | 2011-04-13 | 天津理工大学 | Method for flattening diamond film by using composite process |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8734661B2 (en) | 2007-10-15 | 2014-05-27 | Ebara Corporation | Flattening method and flattening apparatus |
-
2001
- 2001-05-23 JP JP2001153758A patent/JP3734722B2/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1318156C (en) * | 2004-12-23 | 2007-05-30 | 彭彤 | Manufacturing method of diamond wire drawing mould |
| US7776228B2 (en) | 2006-04-11 | 2010-08-17 | Ebara Corporation | Catalyst-aided chemical processing method |
| US8679286B2 (en) | 2006-04-11 | 2014-03-25 | Ebara Corporation | Catalyst-aided chemical processing method |
| EP1894900A3 (en) * | 2006-08-28 | 2010-02-24 | Osaka University | Catalyst-aided chemical processing method and apparatus |
| JP2008136983A (en) * | 2006-12-05 | 2008-06-19 | Osaka Univ | Catalyst-aided chemical processing method and apparatus |
| JP2010188487A (en) * | 2009-02-19 | 2010-09-02 | Kumamoto Univ | Catalyst support type chemical machining method, and machining apparatus using the same |
| CN102011106A (en) * | 2010-09-07 | 2011-04-13 | 天津理工大学 | Method for flattening diamond film by using composite process |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3734722B2 (en) | 2006-01-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101110682B1 (en) | Water-based polishing slurry for polishing silicon carbide single crystal substrate, and polishing method for the same | |
| Shi et al. | Characterization of colloidal silica abrasives with different sizes and their chemical–mechanical polishing performance on 4H-SiC (0 0 0 1) | |
| JP5644175B2 (en) | Graphene deposition method on SiC substrate | |
| Pan et al. | Chemical mechanical polishing (CMP) of on-axis Si-face 6H-SiC wafer for obtaining atomically flat defect-free surface | |
| JP2850803B2 (en) | Wafer polishing method | |
| Deng et al. | Plasma-assisted polishing of gallium nitride to obtain a pit-free and atomically flat surface | |
| CA1061691A (en) | Preparation of damage-free surface on alpha-alumina | |
| TWI748260B (en) | High-flatness, low-damage large-diameter single crystal silicon carbide substrate and preparation method thereof | |
| TW201021112A (en) | Method for polishing a semiconductor wafer provided with a strain-relaxed layer of Si1-xGex | |
| Deng et al. | Competition between surface modification and abrasive polishing: a method of controlling the surface atomic structure of 4H-SiC (0001) | |
| WO2021078237A1 (en) | Method for polishing large-size single crystal diamond | |
| Luo et al. | Atomic-scale and damage-free polishing of single crystal diamond enhanced by atmospheric pressure inductively coupled plasma | |
| JP5267177B2 (en) | Method for manufacturing silicon carbide single crystal substrate | |
| WO2021078247A1 (en) | Large-size single crystal diamond grinding method | |
| JP2007311586A (en) | Method for finish polishing surface of silicon carbide single crystal wafer | |
| JP2004181584A (en) | Polishing composite material, grinding wheel, grinding material, polishing material, working method of electronic part, and working method of silicon | |
| JP2002346915A (en) | Chemical mechanical polishing method for diamond thin film | |
| JP3668647B2 (en) | Semiconductor wafer substrate regeneration method and semiconductor wafer substrate regeneration polishing liquid | |
| Yin et al. | Investigation of SiC single crystal polishing by combination of anodic oxidation and mechanical polishing | |
| Lu et al. | Precision polishing of single crystal diamond (111) substrates using a sol-gel (SG) polishing pad | |
| TW568813B (en) | Polishing agent, method of producing this agent, and method of polishing | |
| CN114940886A (en) | Nano alumina abrasive particle, preparation method and application thereof, and silicon carbide polishing solution containing abrasive particle | |
| CN113089093B (en) | Method for forming diamond semiconductor structure | |
| TW502329B (en) | Polishing process for manufacturing dopant-striation-free polished silicon wafers | |
| Liu et al. | Effects of compound diamond slurry with graphene for lapping of sapphire wafers |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20051006 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20051018 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20051019 |
|
| R150 | Certificate of patent (=grant) or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20091028 Year of fee payment: 4 |
|
| LAPS | Cancellation because of no payment of annual fees |