JP3638138B2 - Wafer holding disk manufacturing method and wafer polishing method - Google Patents

Description

【００９４】
（比較例２）
面出し研磨の研磨圧力を２００ｇ／ｃｍ²、ウエーハの研磨圧力を２００ｇ／ｃｍ²とした以外は比較例１と同様にウエーハ保持盤を作製し、またウエーハの研磨も同様に行った。
【００９５】
本比較例のウエーハ保持盤においては、比較例１のウエーハ保持盤よりは吸着孔の周りのだれは小さくなっていた。しかし、本比較例のウエーハ保持盤でウエーハを研磨したところ、表１に示したごとく、ナノトポグラフィーのＰＶ値の最大値は４２ｎｍとあまり改善されていなかった。
【００９６】
本比較例の結果から、面出し研磨の研磨圧力を低くするほど、ナノトポグラフィーは改善される傾向にあるが、面出し研磨の圧力を制御しただけでは不十分であることが判明した。
【００９７】
(実施例２)
ウエーハ保持盤基体の吸着孔に充填材を充填しない状態で、面出し研磨の研磨圧力を２００ｇ／ｃｍ²とした以外は実施例１と同様にしてウエーハ保持盤を作製した。
【００９８】
作製したウエーハ保持盤の吸着孔付近の形状を観察した結果、わずかにだれは見られるものの吸着孔の周りはほとんど平らであった。
【００９９】
また、この作製したウエーハ保持盤を用い、ウエーハを研磨した。ウエーハの研磨条件は実施例１のウエーハ保持盤を用いウエーハを研磨したときと同様（ウエーハの研磨圧力＝４００ｇ／ｃｍ²）とした。
【０１００】
つまり、本実施例は、面出し研磨の研磨圧力をウエーハの研磨圧力（４００ｇ／ｃｍ²）の半分（２００ｇ／ｃｍ²）にした例である。
【０１０１】
このような条件でウエーハ保持盤を作製し、これを用いて研磨した場合、表１に示したごとく、ウエーハのナノトポグラフィーのＰＶ値の最大値は２９ｎｍと、面出し研磨の研磨圧力を２００ｇ／ｃｍ²、ウエーハの研磨圧力を２００ｇ／ｃｍ²とした比較例２に比べ改善されていることが判明した。
【０１０２】
通常、面出し研磨の絶対的な研磨圧力を低下させれば、吸着孔付近の悪化が防止されると考えられるが、それだけでは不十分でナノトポグラフィーを改善するには面出し研磨時の研磨圧力と、ウエーハの研磨圧力の関係が重要であることがわかる。
【０１０３】
（比較例３）
面出し研磨の研磨圧力を４００ｇ／ｃｍ²、ウエーハの研磨圧力を２００ｇ／ｃｍ²とした以外は比較例１と同様にしてウエーハ保持盤を作製し、ウエーハの研磨も同様に行った。つまり、面出し研磨の研磨圧力（４００ｇ／ｃｍ²）をウエーハ研磨圧力（２００ｇ／ｃｍ²）の倍にして処理した。
【０１０４】
作製したウエーハ保持盤の吸着孔付近の形状を観察した結果、比較例１と同様に吸着孔の周りが約０．５から１ｍｍ程度の範囲でだれていた。
【０１０５】
この作製したウエーハ保持盤を用い、ウエーハを研磨した後、そのウエーハ表面のナノトポグラフィーについて評価した。本比較例のウエーハ保持盤を用いて研磨した場合、表１に示したごとく、ウエーハのナノトポグラフィーのＰＶ値の最大値は３９ｎｍであった。
【０１０６】
この測定結果からウエーハの研磨圧力が低いのでナノトポグラフィーの悪化は若干は改善されるものの十分ではないことがわかった。
【０１０７】
（実施例３）
ウエーハ保持盤基体の吸着孔に充填材を充填しない状態で、面出し研磨の研磨圧力を２段階に変化させて面出し加工を実施した。つまり、ウエーハ保持盤基体の面出し研磨を、はじめにウエーハ研磨圧力と同等の研磨圧力（本実施例では４００ｇ／ｃｍ²）で実施し、次いで研磨圧力を２００ｇ／ｃｍ²に低下させて研磨し、ウエーハ保持盤を作製した。
【０１０８】
次に、この作製したウエーハ保持盤を用い、ウエーハの研磨処理を行った。ウエーハの研磨条件は、実施例１と同様（研磨圧力４００ｇ／ｃｍ²）とした。
【０１０９】
作製したウエーハ保持盤の吸着孔付近の形状を観察した結果、わずかにだれは見られるものの吸着孔の周りはほとんど平らであった。
【０１１０】
この作製したウエーハ保持盤を用いてウエーハを研磨した場合、表１に示したごとく、ウエーハのナノトポグラフィーのＰＶ値の最大値は２７ｎｍと良好であった。
【０１１１】
この測定結果から、ウエーハ保持盤基体の面出し研磨を行う場合、面出し研磨の最終的な研磨圧力がウエーハのナノトポグラフィーに特に影響していることが考えられる。
【０１１２】
このように吸着孔に充填材を充填しなくても、面出し研磨時の研磨圧力と、ウエーハの研磨圧力の関係を考慮することである程度のナノトポグラフィーの改善は可能である。この場合、面出し研磨時の研磨圧力及びウエーハの研磨圧力のみで制御する場合、工程としては少ないため簡便に実施できるという利点がある。
【０１１３】
（実施例４）
吸着孔に充填材を充填した状態で、面出し研磨の研磨圧力をウエーハ研磨圧力より低くした例を示す。
【０１１４】
あらかじめウエーハ保持盤基体の吸着孔に実施例１と同様の充填材を充填して、更に実施例３と同様に面出し研磨時の研磨圧力をウエーハの研磨圧力より低く（本実施例では３００ｇ／ｃｍ²）し、ウエーハ保持盤の作製を行った。この場合も吸着孔の周りはほとんど平らであり、吸着孔（直径０．２５ｍｍ）をそのまま維持しており同じ効果が得られた。
【０１１５】
作製したウエーハ保持盤を用い、実施例１と同様の条件でウエーハを研磨したところ、表１に示したごとく、ウエーハのナノトポグラフィーのＰＶ値の最大値は約２５ｎｍと良好な面状態であった。
【０１１６】
面出し研磨時の研磨圧力及びウエーハの研磨圧力のみで制御する場合、工程としては少ないため簡便に実施できるという利点はあるものの、それぞれの研磨圧力をどの程度にすればよいか等の予備実験等が必要な場合もある。またウエーハ又はウエーハ保持盤の保持面を研磨する場合、研磨圧力が高ければ研磨能力も高いため好ましい場合もあり、このような高圧力条件、またはその他の研磨条件に影響されず確実にナノトポグラフィーを改善するには充填材の充填を併用することが好ましい。充填材の充填を行い面出し研磨を行えば、研磨条件等の影響も少なく簡便に良好なウエーハ保持盤のウエーハ保持面を形成できる。
【０１１７】
なお、本発明は、上記実施形態に限定されるものではない。上記実施形態は、例示であり、本発明の特許請求の範囲に記載された技術的思想と実質的に同一な構成を有し、同様な作用効果を奏するものは、いかなるものであっても本発明の技術的範囲に包含される。
【０１１８】
例えば、本実施例では製品を研磨する研磨圧力を４００ｇ／ｃｍ²の条件を中心に説明したが、研磨圧力やその他の研磨条件等は任意である。現状用いられている研磨装置及び研磨剤等の条件では、面出し加工の研磨圧力は１００〜３００ｇ／ｃｍ²程度、ウエーハの研磨圧力は２００〜５００ｇ／ｃｍ²程度が好ましい。また、面出し加工のラッピング工程は必ずしも入れる必要が無い。なお、本実施例の形態で充填材を充填する場合、ラッピング処理（例えば図２のサブステップ１０２ｂ）の前に実施していたが、これはラッピング処理後、研磨前（例えば図２のサブステップ１０２ｃの前）に実施しても良い。
【０１１９】
さらに、上記のようなウエーハ保持盤の面出し加工は、ウエーハを研磨する前に行うのが通常であるが、ウエーハを研磨するにつれ、研磨布の経時変化が起こることもあるので、これに対応させ、面出し加工をやり直す等しても良い。この場合も本発明のウエーハ保持盤の作製方法を適用して行うと良い。
【０１２０】
【発明の効果】
以上説明したように、本発明によれば、高精度のウエーハ保持面を有する研磨用ウエーハ保持盤が提供される。従って、このウエーハ保持盤を備えた研磨装置を用いてウエーハの研磨加工を行えば、優れた平坦度とうねりのない表面を持ったウエーハを作製することが出来る。特に、ウエーハが、本発明の研磨用ウエーハ保持盤を用いて研磨加工された半導体ウエーハの場合は、ナノトポグラフィーも改善され、高集積デバイス工程でのＣＭＰにおける研磨不良を低減することが可能であり、高集積デバイスの歩留り向上を図ることができる。
【図面の簡単な説明】
【図１】 本発明のウエーハ保持盤の作製方法の第１の態様の工程順を模式的に示す説明図である。
【図２】 本発明のウエーハ保持盤の作製方法の第１の態様の工程順を示すフローチャートである。
【図３】 本発明のウエーハ保持盤の作製方法の第２の態様の工程順を模式的に示す説明図である。
【図４】 本発明のウエーハ保持盤の作製方法の第２の態様の工程順を示すフローチャートである。
【図５】 本発明のウエーハ保持盤の作製方法の第３の態様の工程順を示すフローチャートである。
【図６】 本発明のウエーハ保持盤の作製方法の第４の態様の工程順を示すフローチャートである。
【図７】 本発明のウエーハ保持盤の作製方法の第５の態様の工程順を示すフローチャートである。
【図８】 本発明のウエーハの研磨方法の工程順を示すフローチャートである。
【図９】 本発明のウエーハの研磨方法で用いるウエーハ研磨装置の一例を示す概略説明図である。
【図１０】 図９に示したウエーハ研磨装置でウエーハを保持しない状態を示す概略説明図である。
【図１１】 本発明のウエーハ保持盤の作製方法によって作製したウエーハ保持盤のウエーハ保持面の１例を示す平面図である。
【図１２】 実施例１及び比較例１において作製したウエーハ保持盤の吸着孔付近の形状変化を示すグラフである。
【図１３】 実施例１及び比較例１において研磨したウエーハのナノトポグラフィーを示すグラフである。
【符号の説明】
１０：研磨装置、１２：定盤、１２ａ：研磨布、１４：研磨ヘッド、１４ａ：回転軸、１６：研磨剤供給管、１６ａ：研磨剤、１８：回転軸、２０：裏板、２２：外カバー、２４：真空部、２８：吸引路、３０：ウエーハ保持盤、３０Ａ：ウエーハ保持盤基体、３０ａ：ウエーハ保持盤本体、３０ｂ：樹脂膜、３１：加圧部、３２：吸着孔、３２ａ：吸着孔本体、３２ｂ：吸着孔部、３３：加圧空気供給路、３４ａ：ウエーハ保持面本体、３４ｂ：ウエーハ保持面、３６：充填材、Ｗ：ウエーハ。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a wafer holding disk used in a polishing apparatus used when polishing the surface of a wafer such as a semiconductor wafer, and a method for polishing a wafer using a polishing apparatus equipped with the wafer holding disk.
[0002]
[Related technologies]
Conventionally, in polishing, a plate of rigid material such as glass, metal, or ceramic is used as a wafer holding plate, and a wafer is attached to the surface with an adhesive such as wax, or a porous material or air permeable material is attached to the surface. A method of holding a wafer by vacuum suction or the like on the surface of a wafer holding plate provided with a large number of suction holes has been performed.
[0003]
However, if the wafer is held directly on the surface of a wafer holding plate made of metal, ceramics, or the like, scratches and dirt are generated on the back surface of the wafer. In order to prevent such contamination of the wafer, the surface of the wafer holding plate is coated with a material known as ultrathin Teflon (registered trademark), nylon, etc. of several tens of μm, or a resin film such as vinyl chloride, Wafer holding with a thin acrylic resin plate (resin plate) attached with an adhesive, or epoxy resin that is a thermosetting resin applied and cured to form a coated resin film on the surface of the wafer holder A board has been proposed.
[0004]
In addition, when polishing a wafer, even if the surface of the wafer holding plate is finished to a high flatness, the surface of the polishing cloth gradually changes due to the creep deformation of the polishing cloth. There are not limited problems. Regarding this, the resin surface of the wafer holding disk in which a resin film was formed on the wafer holding disk was previously polished by a polishing apparatus (specifically, a polishing cloth) for polishing the wafer, thereby following the creep deformation of the polishing cloth. The surface of the wafer holding plate is adjusted by making the surface of the wafer holding plate or the like (hereinafter, this process may be referred to as a chamfering process).
[0005]
[Problems to be solved by the invention]
As described above, the wafer holding plate having the wafer holding surface coated with the resin film is polished in advance by a polishing apparatus (specifically, polishing cloth) for polishing the wafer, and is adjusted to the shape of the polishing cloth. However, when the wafer is held and polished, the waviness and the overall flatness are remarkably improved, but the nanotopography level unevenness is sometimes deteriorated.
[0006]
Nanotopography (also referred to as nanotopology) is unevenness having a wavelength of about 0.1 mm to 20 mm and an amplitude of about several nm to 100 nm. As an evaluation method, one side is about 0.1 mm to 10 mm. The height difference (PV: peak to valley) of the wafer surface is evaluated in an area of a square or a circular block range having a diameter of about 0.1 mm to 10 mm (this range is called WINDOW SIZE etc.). This PV value is also called Nanotopography Height or the like. As nanotopography, it is desired that the maximum value of the unevenness existing in the evaluated wafer surface is small. Usually, a plurality of block ranges are evaluated with a square of 2 mm, and the maximum PV value is evaluated. The smaller this value, the better the product.
[0007]
The unevenness at the nanotopography level may cause a problem in CMP (Chemical Mechanical Polishing) performed in a device process, for example. For example, in the process of forming a groove with a depth of less than 1 micron between elements, filling the groove with an oxide film, polishing the excess oxide film by CMP, and planarizing the element region while isolating elements, If the nanotopography level of the wafer before formation is poor (if there are large irregularities on the wafer surface), even if the polishing process is completed and the element is separated on the convex part of the wafer surface, an oxide film still remains in the concave part. This causes a problem of poor polishing that the separation structure is not well formed.
[0008]
The deterioration of the nanotopography level is caused when the wafer holding surface of the wafer holding disk is being manufactured and the shape near the suction hole deteriorates. When the wafer is held on this wafer holding surface and polished, It is considered that the shape near the hole is transferred to the wafer, and the unevenness at the nanotopography level becomes worse.
[0009]
The present invention has been made in view of the above problems, and prevents the shape near the suction holes on the wafer holding surface of the wafer holding disk from being transferred to the wafer, and also prevents deterioration of irregularities on the nanotopography level. A method of manufacturing a wafer holding disk, which can improve problems such as polishing defects in CMP in a process, improve the yield of highly integrated devices, and can easily manufacture a wafer holding surface, and this It is a main object of the present invention to provide a wafer polishing method using a polishing apparatus having a wafer holding plate.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a first aspect of the method for manufacturing a wafer holding disk according to the present invention is to manufacture a wafer holding disk capable of holding the wafer by vacuum suction holding on the wafer holding surface when the wafer is polished. A wafer holding surface body of a wafer holding disk body having a plurality of suction hole bodies is coated with a resin film so that the resin film surface becomes a wafer holding surface, and suction hole portions communicating with the suction hole body are formed. A step of creating a wafer holder base having a large number of suction holes by opening the resin film, and polishing the resin film in a state where the suction holes of the wafer holder base are filled with a filler. And a step of performing a chamfering process on the wafer holding surface and adjusting the wafer holding surface.
[0011]
By performing the chamfering process of the wafer holding surface of the wafer holding plate in a state in which the adsorption holes are filled with the filler as described above, the expansion of the adsorption hole part during the chamfering process is reduced, and deterioration of the nanotopography can be prevented. .
[0012]
In the polishing process of the silicon wafer, processing is performed by a combination of chemical action and mechanical action, but in the chamfering process, the resin film that is not easily etched by the alkaline solution is chamfered using an alkaline abrasive, It is considered that the mechanical action is mainly affected. As described above, it is preferable to perform the chamfering process (particularly the polishing process) after filling the suction holes with the filler.
[0013]
In particular, the filler is preferably a material having properties equivalent to those of the resin film. That is, as the filler, a material that is difficult to be etched into the alkaline solution and easily filled into the adsorption hole is selected.
[0014]
Further, a second aspect of the method for producing a wafer holding disk of the present invention is a method for producing a wafer holding disk in which the wafer can be vacuum-sucked and held on the wafer holding surface when polishing the wafer, A wafer holding surface body of a wafer holding board body having a large number of suction hole bodies is coated with a resin film to make the surface of the resin film a wafer holding surface, and an adsorption hole portion communicating with the suction hole body is opened in the resin film. Forming a wafer holding disk substrate having a plurality of suction holes and polishing the resin film at a pressure lower than the polishing pressure when polishing the wafer, and performing a chamfering process on the wafer holding surface. And a step of adjusting the wafer holding surface.
[0015]
In general, it is considered that the polishing pressure of the wafer holding surface is preferably the same as the polishing pressure of the wafer. However, in the present invention, the polishing pressure of the wafer holding surface is set lower than the polishing pressure of the wafer. In this way, when the wafer holding surface is polished, the processing is performed at a pressure lower than the pressure at the time of polishing the wafer, so that the adsorption hole is not deteriorated so as to affect the polishing of the wafer. Get better. The polishing pressure for polishing the wafer holding surface is preferably about 90% to 10% of the polishing pressure for polishing the wafer.
[0016]
In particular, in the second embodiment of the method for producing the wafer holding disk of the present invention in which the suction holes are not filled with the filler, the polishing pressure itself when polishing the wafer holding surface (surface polishing) is 300 g / cm. ² Or less, preferably 200 g / cm ² The following is preferable.
[0017]
When the pressure for polishing the wafer is low, for example, 200 g / cm ² If it is about the same level, the polishing pressure for polishing the wafer holding surface may be set slightly lower than the pressure for polishing the wafer. On the other hand, when the polishing pressure of the wafer is high, if it is almost equal to the pressure when polishing the wafer, the pressure at the time of surface polishing will increase, and the mechanical action will work too much and the vicinity of the adsorption hole may be scraped excessively. is there. This is because the scraped material leads to deterioration of the suction holes to the extent that it affects the wafer polishing. Thus, for example, 400 g / cm ² When polishing a wafer with a moderate pressure, surface polishing is 300 g / cm. ² It is preferable to make the following degree.
[0018]
Furthermore, a third aspect of the method for producing a wafer holding plate of the present invention is a method for producing a wafer holding plate which allows the wafer to be vacuum-sucked and held on the wafer holding surface when polishing the wafer, A wafer holding surface body of a wafer holding board body having a large number of suction hole bodies is coated with a resin film to make the surface of the resin film a wafer holding surface, and an adsorption hole portion communicating with the suction hole body is opened in the resin film. Forming a wafer holding disk substrate having a plurality of suction holes and filling the suction holes of the wafer holding disk substrate with a filler, and at a pressure equal to or lower than the polishing pressure when polishing the wafer. And polishing the resin film to perform a chamfering process on the wafer holding surface and adjusting the wafer holding surface.
[0019]
In other words, when the filler and the wafer holding surface are polished, processing is performed at a pressure equal to or lower than that when the wafer is polished, so that the adsorption hole portion is reduced and the conditions for processing the wafer holding surface and the wafer are processed. The condition relationship is good and nanotopography is good. In this case, when the polishing pressure for polishing the wafer is high (for example, 400 g / cm ² However, the polishing pressure for surface polishing is increased (400 g / cm, the same as the wafer polishing pressure). ² Degree and less).
[0020]
A fourth aspect of the method for producing a wafer holding disk according to the present invention is a method for producing a wafer holding disk, in which when the wafer is polished, the wafer can be vacuum-sucked and held on the wafer holding surface. The wafer holding surface body of the wafer holding plate body having the suction hole body is coated with a resin film so that the surface of the resin film is used as a wafer holding surface, and the suction hole portion communicating with the suction hole body is opened in the resin film. Forming a wafer holding disk substrate having a plurality of suction holes, polishing the resin film at a pressure equal to or lower than the polishing pressure when polishing the wafer, and chamfering the wafer holding surface, And adjusting the wafer holding surface, and polishing the resin film of the wafer holding disk by changing the polishing pressure in at least two stages.
[0021]
A fifth aspect of the method for manufacturing a wafer holding disk according to the present invention is a method for manufacturing a wafer holding disk in which the wafer can be vacuum-sucked and held on the wafer holding surface when the wafer is polished. The wafer holding surface body of the wafer holding plate body having the suction hole body is coated with a resin film so that the surface of the resin film is used as a wafer holding surface, and the suction hole portion communicating with the suction hole body is opened in the resin film. Forming a wafer holding base having a plurality of suction holes, and filling the suction holes of the wafer holding base with a filler, and at a pressure equal to or lower than the polishing pressure when polishing the wafer And polishing the wafer holding surface to adjust the wafer holding surface, and polishing the resin film of the wafer holding plate. Characterized by polishing instead of the at least two stages of pressure.
[0022]
As in the fourth and fifth aspects of the method for manufacturing the wafer holding disk of the present invention described above, the resin film on the wafer holding surface is formed regardless of whether the suction holes of the wafer holding disk substrate are filled with a filler. When performing the chamfering process, it is possible to form an even better surface state by performing the polishing process while changing the polishing pressure in at least two stages. For example, the first-stage polishing pressure is equal to the wafer polishing pressure, the shape of the entire wafer holding surface is created, and the second-stage polishing pressure is not particularly limited. Try to create the shape around the hole. At this time, the polishing pressure may be changed continuously or stepwise.
[0023]
In this way, first, in the same manner as the polishing conditions for polishing the product, the wafer holding surface is polished to form a wafer holding disk following the polishing cloth, and then the pressure is reduced and the wafer holding disk is gently polished. As a result, the expansion of the adsorption hole portion is reduced and the nanotopography is improved.
[0024]
In the method for producing a wafer holding disk of the present invention, it is preferable that the wafer holding surface is chamfered by polishing the resin film using a polishing apparatus for polishing the wafer. In this way, it is possible to perform accurate copying polishing that matches the shape of the polishing pad.
[0025]
Furthermore, in the method for manufacturing the wafer holding disk of the present invention, the wafer holding surface is chamfered by using a device equivalent to a polishing device for polishing the wafer and polishing the resin film in advance by external setup. It can be carried out. The term “outside setup” as used herein means that the work holding plate is subjected to surface polishing in advance by a polishing apparatus different from the polishing apparatus for polishing the wafer. This is the same specification as the apparatus for polishing the wafer, for example, the hardness of the polishing cloth having a large influence on the wafer holding surface, so that the holding surface is in the same state as the polishing apparatus for polishing the actual wafer. It is to process in advance. If the wafer holding plate is processed in this way, the operating rate of the apparatus for polishing the wafer can be improved.
[0026]
The chamfering process of the wafer holding surface is preferably performed by lapping using loose abrasive grains and then polishing the resin surface.
[0027]
The surface of the wafer holding plate, that is, the surface of the resin film is first corrected by lapping and then corrected by polishing on the surface plate of the polishing apparatus to form a wafer holding surface of the wafer holding plate with higher accuracy. it can. By using this wafer holding plate, wafer polishing with high flatness can be performed.
[0028]
As resin which comprises the said resin film, it can be set as 1 type selected from the group which consists of an epoxy resin, unsaturated polyester resin, a urethane resin, and a phenol resin. If the material of the resin film is selected from the above-mentioned resins, it is possible to satisfy the film physical properties, such as hardness, mechanical strength, and linear expansion coefficient, which are required in the method for producing the wafer holder of the present invention. In particular, an epoxy resin is preferable.
[0029]
The thickness of the resin film covering the wafer holding surface main body of the wafer holding disk main body is preferably 0.1 to 3 mm. As described above, if the thickness of the resin film is 3 mm or less, the rigidity of the wafer holding disk main body is not lowered. Therefore, more accurate wafer polishing can be performed, and if the thickness is 0.1 mm or more, high flatness is achieved. Is obtained.
[0030]
The hole diameter of the suction hole body of the wafer holding disk body is preferably about 0.1 mm to 0.3 mm in consideration of the suction force and the like. In particular, the larger the diameter of the wafer, the larger the spread of the adsorption holes. This is because the contact with the polishing cloth is considered to be a particular problem. Therefore, it is preferable that the suction holes are small. On the other hand, if the suction holes are too small, the wafer holding power is reduced, and the wafer may be detached during polishing. In addition, there is a problem that the suction holes are easily clogged, and the hole diameter of the suction holes is particularly preferably 0.15 mm or more and 0.25 mm or less.
[0031]
It is preferable to form a resin film having an adsorption hole by forming a thermosetting resin film on the wafer holding surface main body of the wafer holding disk main body and then mechanically forming the adsorption hole in the resin film. It is.
[0032]
The method of forming the resin film for covering the wafer holding board body is not particularly limited. For example, a thermosetting resin is applied to the wafer holding surface body of the wafer holding board body, and this is coated with a heat-cured film. If the resin film surface is polished as described above, a uniform resin film can be formed. As a result, there is no problem that unevenness of the thickness of the resin film is transferred to the surface of the wafer, and the wafer holding surface formed with high accuracy by the resin film achieves a desired high flatness and high accuracy wafer polishing without waviness. Is possible. Further, the size of the adsorption hole can be made uniform by mechanically forming the adsorption hole of the resin film. However, the method of forming the resin film that covers the wafer holder main body is not limited to this.
[0033]
Further, the wafer polishing method of the present invention uses a wafer holding disk produced by the method as described above and a polishing apparatus equipped with a polishing cloth to hold the back surface of the wafer by vacuum adsorption holding on the wafer holding surface of the wafer holding disk, Next, the wafer is brought into contact with the polishing cloth to polish the surface of the wafer.
[0034]
According to the wafer polishing method of the present invention, it is possible to polish using a wafer holding plate that does not deteriorate the shape in the vicinity of the suction holes, and it is possible to polish a wafer with high flatness and no waviness, particularly after wafer polishing. Generation of irregularities on the nanotopography level can be prevented.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. However, it is needless to say that the illustrated examples are illustrative and the present invention is not limited to these embodiments.
[0036]
FIG. 1 is an explanatory view schematically showing the process sequence of the first embodiment of the method for manufacturing a wafer holding disk of the present invention, and FIG. 2 is a flowchart showing the process sequence of the above. First, a wafer holding base 30A having suction holes is created (step 100 in FIG. 2). Specifically, first, a wafer holding board main body 30a having a suction hole main body 32a is prepared [FIG. 1 (a), sub-step 100a in FIG. 2].
[0037]
The material of the wafer holding board main body 30a is not particularly limited, but a material having high rigidity and high corrosion resistance that is not easily corroded by the polishing liquid or the like is preferable. Further, if the wafer holding plate body 30a is formed of a material having a low thermal expansion coefficient, a wafer holding surface 34b of a wafer holding plate base 30A, which will be described later, is polished on the polishing apparatus surface plate (FIG. 1 (e)). ] And the difference in thermal deformation of the wafer holding plate body 30a when polishing the wafer can be reduced, so that the shape of the wafer holding surface 34b (FIG. 1G) of the high-precision wafer holding plate 30 to be described later is maintained. Therefore, wafer polishing with high flatness can be performed. As described above, the linear thermal expansion coefficient of the material of the wafer holding disk main body 30a is 1 × 10. ^-Five It is desirable that the temperature of the wafer holding disk main body 30a is, for example, a sintered body (ceramics) of silicon carbide (SiC). Hereinafter, an example in which silicon carbide is used as the material of the wafer holding board main body 30a will be described.
[0038]
The wafer holding board body 30a is provided with a suction hole body 32a for vacuum suction, and the suction hole body 32a preferably has a hole diameter of about 0.1 to 0.3 mm.
[0039]
Next, the resin film 30b is coated on the wafer holding surface main body 34a of the wafer holding board main body 30a described above (FIG. 1B, sub-step 100b in FIG. 2). The resin film 30b used in the present invention is not particularly limited, but for example, one type selected from the group consisting of epoxy resins, unsaturated polyester resins, urethane resins, and phenol resins that are thermosetting resins is used. Can do. Among the above-mentioned resins, the epoxy resin can sufficiently satisfy the requirements for hardness, mechanical strength, linear expansion coefficient, etc., which are film physical properties after thermosetting required in the method for producing a wafer holder of the present invention. . Hereinafter, an example in which an epoxy resin is used as the resin film 30b will be described.
[0040]
Various methods are conceivable for coating the resin holding film 30b on the wafer holding disk main body 30a. In the following example, a case where a resin is applied to the surface of the wafer holding disk main body 30a will be described.
[0041]
First, a thermosetting resin (epoxy resin) is charged into a stirring and mixing tank and sufficiently degassed under vacuum to remove air. The wafer holding plate body 30a is placed on the resin application jig with the wafer holding surface main body 34a facing upward, and the coating amount adjusting plate is set, and then the thermosetting resin is poured onto the wafer holding surface main body 34a. .
[0042]
A bar is slid on the coating amount adjusting plate to scrape excess resin, thereby forming a resin film 30b having a uniform thickness. The thickness of the resin film 30b that covers the wafer holding surface body 34a of the wafer holding board body 30a is preferably 0.1 to 3 mm. As described above, if the thickness of the resin film 30b is 3 mm or less, the rigidity of the wafer holding disk main body 30a is not lowered. Therefore, more accurate wafer polishing can be performed, and if it is 0.1 mm or more, it is high. Flatness is obtained.
[0043]
The wafer holding board body 30a coated with the resin is placed in an electric heating furnace together with a resin coating jig, and the entire resin film 30b is thermally cured.
[0044]
Next, a portion of the resin film 30b corresponding to the suction hole main body 32a of the wafer holding disk main body 30a is mechanically opened using a drill to form the suction hole 32b [FIG. 1 (c), FIG. Sub-step 100c].
[0045]
By the above-described procedure, the wafer holding surface body 34a is covered with the resin film 30b, and the wafer holding disk base 30A having the wafer holding surface 34b is formed (step 100 in FIG. 2). The formation of the resin film 30b is an example and may be formed by other methods.
[0046]
The method for producing a wafer holding disk according to the present invention is characterized by a process (surface forming process) when the wafer holding surface 34b formed in this way is copied to a polishing cloth of a polishing apparatus described later. The aspect will be further described.
[0047]
In the first aspect of the method for manufacturing the wafer holding disk of the present invention, as shown in FIG. 1 (d), the suction hole 32 of the wafer holding disk base 30A on which the resin film 30b is formed is filled with a filler 36. The wafer holding surface 34b is processed (surface forming) (step 102 in FIG. 2).
[0048]
That is, as described above, after the wafer holding base 30A is formed, the suction hole 32 is filled with the filler 36 [FIG. 1 (d), sub-step 102a in FIG. 2]. The material of the filler 36 is not particularly limited, but a material having the same properties as the resin film 30b is preferable. When the resin film 30b is an epoxy resin, the suction hole 32 is filled with a needle-shaped epoxy resin or an epoxy resin before thermosetting, and the filler 36 is inserted into the suction hole 32 by, for example, natural drying. The wafer holding surface 34b is subjected to a chamfering process in a state where 32 is closed [FIG. 1 (e), sub-step 102c of FIG. 2].
[0049]
The chamfering process may be performed by external setup using a polishing apparatus for polishing the wafer or an apparatus equivalent to a wafer polishing apparatus, and finally polishing the wafer holding surface 34b. The coated wafer holding plate body 30a may be set in a wrapping machine, and a process of correcting the surface by grinding the surface of the resin film 30b by dropping the lapping solution from the nozzle while rotating the surface plate may be included (see FIG. 2). Sub-step 102b). Moreover, you may put a washing | cleaning process after that.
[0050]
The lapping conditions are not particularly limited, but a single-sided lapping device is used, the wafer holding plate on which the resin film is formed is set on the wafer holding plate portion of the lapping device, and the holding surface is lapped.
[0051]
The wafer holding disk body having been subjected to the lapping correction in this way is set in, for example, a polishing apparatus that polishes the wafer, and the surface of the resin film is polished by dripping an abrasive from the nozzle while rotating the surface plate to correct the surface. Do. At this time, processing may be performed by external setup using an apparatus equivalent to an apparatus for polishing a wafer.
[0052]
The wafer polishing apparatus used at this time is not particularly limited. For example, an apparatus as shown in FIG. 9 can be used. FIG. 9 is a schematic explanatory view showing an example of a wafer polishing apparatus used in the wafer polishing method of the present invention.
[0053]
In FIG. 9, the polishing apparatus 10 includes a rotating surface plate (rotary table) 12, a wafer holding plate 30 attached to the polishing head 14, and an abrasive supply pipe 16.
[0054]
A polishing cloth 12 a is attached to the upper surface of the surface plate 12. The surface plate 12 is rotated at a predetermined rotation speed by the rotation shaft 18. The abrasive 16a is supplied from the abrasive supply pipe 16 onto the polishing cloth 12a.
[0055]
As shown in FIG. 11, the wafer holding plate 30 holds and polishes the wafer W on the wafer holding surface 34b by vacuum suction or the like through a large number of suction holes 32 formed in the wafer holding surface 34b. It can be done.
[0056]
The polishing head 14 has a back plate 20 and an outer cover 22, and a vacuum part 24 is formed by the back plate 20 and the wafer holding plate 30. Reference numeral 26 denotes an elastic sheet (rubber sheet) provided at the lower end of the back plate 20 and the outer cover 22 so as to seal the vacuum part 24. A suction path 28 is inserted through the vacuum part 24. A pressure member 31 is formed by the back plate 20 and the outer cover 22, and a pressurized air supply path 33 is inserted through the pressure member 31.
[0057]
In the method for manufacturing a wafer holding disk (particularly, chamfering) according to the present invention, as shown in FIG. 10, the wafer holding surface of the wafer holding disk base 30A in advance without holding the wafer W by the polishing apparatus 10 shown in FIG. 34b is processed. In FIG. 10, the same members as those in FIG. 9 are denoted by the same reference numerals.
[0058]
The wafer holding board base 30A is mounted on the polishing head 14 having the rotating shaft 14a and rotated by the polishing head 14, and at the same time, the wafer holding board base 30A is pressed against the polishing cloth 12a with a predetermined load. The polishing agent 16a is supplied onto the polishing cloth 12a from the polishing agent supply pipe 16 at a predetermined flow rate (preferably the same conditions as when the wafer is polished). By being supplied between the cloths 12a, the resin film 30b forming the wafer holding surface 34b is polished.
[0059]
After such polishing, the wafer holding surface 34b is sufficiently cleaned to complete the wafer holding disk 30, and the filler 36 is removed from the suction holes 32 (FIG. 1 (f), sub-step 102d in FIG. 2). The filler 36 can be removed by, for example, air blowing from the back side of the wafer holding plate 30 or water blowing.
[0060]
As described above, the surface of the resin film 30b of the wafer holding plate 30, that is, the wafer holding surface 34b, is first modified by lapping with the suction holes 32 filled with the filler 36 (step 102b in FIG. 2). Then, by correcting the polishing process on the surface plate of the polishing apparatus (step 102c in FIG. 2), the holding surface shape of the holding plate body with higher accuracy can be formed [FIG. 1 (g), FIG. Step 104]. By using this polishing wafer holder 30, wafer polishing with high flatness can be performed.
[0061]
In the first aspect of the method for manufacturing the wafer holding disk of the present invention described above, there is no particular limitation on the polishing pressure at the time of the surface holding processing of the wafer holding surface 34b, and some polishing conditions depend on the polishing amount of the resin film 30b. However, it is usually sufficient to apply a polishing pressure (polishing condition) equivalent to the polishing pressure (polishing condition) when polishing the wafer.
[0062]
Next, a second aspect of the method for manufacturing the wafer holding plate of the present invention will be described. FIG. 3 is an explanatory view schematically showing the process order of the second embodiment of the method for manufacturing the wafer holding disk of the present invention, and FIG. 4 is a flowchart showing the process order of the above. The second aspect of the method for producing the wafer holding disk of the present invention is different from the above-described first aspect in the method of chamfering the wafer holding surface 34b (step 102A in FIG. 4), but the wafer holding disk substrate 30A. Since the creation procedure (step 100 in FIG. 4) is the same, only a different procedure will be described, and a re-explanation of the same procedure will be omitted.
[0063]
The feature of the second aspect of the method for manufacturing the wafer holding disk of the present invention is that the suction hole 32 is opened without filling the suction hole 32 with the filler 36 in the chamfering process of the wafer holding surface 34b. In this state, the wafer holding surface 34b is chamfered (polished), and the polishing pressure during the chamfering polishing is made lower than the polishing pressure during the wafer polishing [FIG. 3 (e1), FIG. Substep 102c1].
[0064]
Specifically, the polishing pressure when polishing the wafer is, for example, 400 g / cm. ² (40 kPa), the polishing pressure during the chamfering process is 400 g / cm. ² Lower and the former is 200 g / cm ² (20 kPa), the latter is 200 g / cm ² It may be lower.
[0065]
The polishing pressure at the time of the above surface processing (polishing) is preferably 90% to 10% of the polishing pressure at the time of wafer polishing, and is 300 g / cm. ² The following is preferable. If surface polishing is performed in such a polishing pressure range, the polishing efficiency is good, the deterioration of the shape near the suction hole 32 can be prevented, and the surface state of the wafer holding surface 34b is also improved.
[0066]
Furthermore, a third aspect of the method for manufacturing the wafer holding disk of the present invention will be described. FIG. 5 is a flowchart showing the process sequence of the third aspect of the method for manufacturing the wafer holding disk of the present invention. The third aspect of the method for manufacturing the wafer holding disk of the present invention is different from the first aspect described above in that the polishing pressure in the chamfering process of the wafer holding surface 34b is limited (step 102B in FIG. 5). Only the difference will be described, and the description of the same procedure will be omitted.
[0067]
The feature of the third aspect of the method for manufacturing the wafer holding disk of the present invention is that the surface of the wafer holding surface 34b is filled by filling the suction holes 32 with the filler 36 in the same manner as in the first aspect. (Polishing) is performed, but the polishing pressure during the surface polishing is limited to be equal to or lower than the polishing pressure during wafer polishing (substep 102c2 in FIG. 5).
[0068]
Specifically, the polishing pressure when polishing the wafer is, for example, 400 g / cm. ² (40 kPa), the polishing pressure during the chamfering process is 400 g / cm. ² And the former is 200 g / cm ² (20 kPa), the latter is 200 g / cm ² The following may be used.
[0069]
Next, the fourth and fifth aspects of the method for manufacturing the wafer holding plate of the present invention will be described. FIG. 6 is a flowchart showing the process sequence of the fourth embodiment of the method for manufacturing a wafer holding plate of the present invention. The fourth aspect of the method for manufacturing the wafer holding disk of the present invention is different from the second aspect described above in that the polishing pressure in the chamfering process of the wafer holding surface 34b is changed in a plurality of stages (step 102C in FIG. 6). ) And only the differences will be described.
[0070]
The feature of the fourth aspect of the method for manufacturing the wafer holding disk of the present invention is that, in the chamfering process of the wafer holding surface 34b, the adsorbing hole 32 is not filled with the filler 36 as in the second aspect. The wafer holding surface 34b is chamfered (polished) while the holes 32 remain open, and the polishing pressure during the chamfering polishing is set to be equal to or lower than the polishing pressure during the wafer polishing and is polished in at least two stages. The processing is performed (substep 102c3 in FIG. 6).
[0071]
FIG. 7 is a flowchart showing the order of steps in the fifth embodiment of the method for manufacturing a wafer holding disc of the present invention. The fifth aspect of the method for manufacturing the wafer holding disk of the present invention is different from the third aspect described above in that the polishing pressure in the chamfering process of the wafer holding surface 34b is changed in a plurality of stages (step 102D in FIG. 7). ) And only the differences will be described.
[0072]
The feature of the fifth aspect of the method for manufacturing the wafer holding disk of the present invention is that the surface of the wafer holding surface 34b is filled by filling the suction holes 32 with the filler 36 in the same manner as in the third aspect. (Polishing) is performed, but the polishing pressure at the time of the surface polishing is set to be equal to or lower than the polishing pressure at the time of polishing the wafer, and at least two stages are used for polishing (substep 102c4 in FIG. 7).
[0073]
As shown in the fourth and fifth aspects described above, the wafer holding surface can be made to have a better surface state by performing the treatment while changing the polishing pressure in two or more stages. For example, the polishing pressure when polishing a wafer is 400 g / cm. ² (40 kPa), the polishing pressure during the chamfering process is 400 g / cm at the beginning. ² And shape the entire adsorption surface at the same polishing pressure as when polishing the wafer, then, for example, 200 g / cm ² Surface polishing may be performed so that the shape in the vicinity of the suction hole is created by changing the polishing pressure to about (half). As described above, when the polishing pressure is changed in two or more steps, it is necessary to finally make the polishing pressure for surface polishing lower than the polishing pressure for the wafer.
[0074]
As described in the first to fifth aspects, a wafer holding disk that follows the polishing cloth can be produced by polishing the resin film on the wafer holding surface.
[0075]
Next, the wafer polishing method of the present invention will be described. FIG. 8 is a flowchart showing the order of steps of the wafer polishing method of the present invention. First, a wafer holding disk manufactured by the above-described method for manufacturing a wafer holding disk of the present invention is prepared (step 200). Next, the wafer holding disk is set in a polishing apparatus (step 202), and the wafer is polished (step 204). As this polishing apparatus, a polishing apparatus used when polishing the resin film of the wafer holding plate described above or an equivalent apparatus can be applied.
[0076]
That is, the polishing apparatus used in the wafer polishing method of the present invention uses the apparatus as shown in FIG. In polishing the wafer, the wafer W is held by vacuum suction or the like on the wafer holding surface 34b of the wafer holding plate 30 attached to the polishing head 14 having the rotating shaft 14a. The wafer W is rotated by the polishing head 14 and simultaneously pressed against the polishing cloth 12a with a predetermined load. The supply of the polishing agent 16a is supplied from the polishing agent supply pipe 16 onto the polishing cloth 12a at a predetermined flow rate, and the polishing agent 16a is supplied between the wafer W and the polishing cloth 12a, whereby the wafer W is polished.
[0077]
The back plate 20 is set on the wafer holding plate 30 of the present invention manufactured by the method for manufacturing the wafer holding plate of the present invention, and the suction hole 32 passes through the vacuum part 24 between the wafer holding plate main body 30a and the back plate 20. The suction path 28 is connected to a vacuum device (not shown), and the wafer W is sucked and held on the wafer holding surface 34b by the generation of vacuum.
[0078]
The polishing head 14 is provided with a pressure unit 31 inside the outer cover 22 and holds the wafer holding plate 30 in an airtight manner via an elastic sheet (rubber sheet) 26. The pressurizing unit 31 is connected to an air compressor (not shown) via a pressurized air supply path 33. Then, the wafer holding plate 30 holding the wafer W by vacuum suction holding on the surface of the resin film 30b on the wafer holding surface 34b is rotated or swinged, and at the same time, the back surface of the wafer holding plate 30 is pressurized with air to hold the wafer. The wafer W is sucked and held on the board 30 and pressed against the polishing pad 12a to polish the wafer W.
[0079]
【Example】
Examples of the present invention will be specifically described below, but the present invention is not limited thereto.
[0080]
The polishing apparatus used in the following examples and comparative examples is of the form shown in FIG. 9. In particular, the wafer holding disk main body is a 30 mm thick silicon carbide (SiC) disk (thermal expansion coefficient 4 × 10). ^-6 / ° C.), and a resin film was coated thereon to form a wafer holding base. The resin film was prepared by the method described in the above embodiment using a thermosetting epoxy resin. The thickness of the produced resin film is 1.5 mm. In the wafer holding disk base, suction holes having a diameter of 0.25 mm are formed on the entire work holding surface at intervals of 8 mm. This condition is common to all examples and comparative examples.
[0081]
(Example 1 and Comparative Example 1)
(Chamfering of wafer holding surface)
The wafer holding surface was processed using the wafer holding disk base described above. First, a filler was filled in the suction holes of the wafer holding base. This filling process was performed by filling the suction holes with the epoxy resin before thermosetting and allowing it to dry naturally.
[0082]
As the chamfering process, lapping and polishing were performed. In the lapping process, the wafer holding disk substrate is set in a single-sided lapping machine, and the wafer holding surface (resin film) is removed by 200 μm using a green silicon carbide wrapping agent (GC # 240 manufactured by Fujimi Incorporated). . This condition is common to all the following examples and comparative examples.
[0083]
Next, the wafer holding surface was polished, and the wafer holding surface (resin film) was polished by 40 μm. The polishing conditions for the chamfering process are polishing pressure of 400 g / cm ² The polishing relative speed was 50 m / min, a non-woven polishing cloth (Asker C hardness 90) was used as the polishing cloth, and an alkaline solution (pH 11.0) containing colloidal silica and crystal silica as the polishing agent was used. After the polishing, the filler was removed from the suction holes by air blowing to produce a wafer holder (Example 1).
.
[0084]
A wafer holding plate was produced in the same manner as in Example 1 except that the epoxy resin filler was not filled in the suction holes of the wafer holding plate base (Comparative Example 1).
[0085]
About the wafer holding disk produced in Example 1 and Comparative Example 1, the shape in the vicinity of the suction hole was measured using a stylus type roughness measuring instrument (for example, Perthometer Persometer S6P), and the result is shown in FIG. It was.
[0086]
As is clear from FIG. 12, in Comparative Example 1, it is found that the area around the suction hole is about 0.5 to 1 mm. This means that the size of the suction hole (diameter 0.25 mm) extends to about 1.25 to 2.25 mm in diameter at the wafer holding portion. In contrast, the method of the present invention (Example 1) is almost flat, and it can be seen that the adsorption holes (diameter 0.25 mm) are maintained as they are.
[0087]
(Wafer polishing)
The wafer holding discs produced in Example 1 and Comparative Example 1 were set and used as wafer holding discs for the polishing apparatus having the structure shown in FIG. As the wafer, a silicon wafer having a diameter of 200 mm and a thickness of 735 μm was used.
[0088]
For wafer polishing, polishing pressure is 400 g / cm. ² The polishing relative speed was 100 m / min, the polishing allowance was 9 μm, the non-woven polishing cloth (Asker C hardness 90) was used as the polishing cloth, and the colloidal silica-containing alkaline solution (pH 10.8) was used as the polishing agent.
[0089]
After polishing, the nanotopography on the wafer surface was evaluated. Nanotopography was measured with Nanomapper (2 mm × 2 mm square area) manufactured by ADE PhaseShift, and the results are shown in FIG.
[0090]
In FIG. 13, the horizontal axis represents the level difference (PV value) of unevenness on the wafer surface when evaluated in each area of 2 mm × 2 mm, and the vertical axis represents the abundance ratio (%) of the area equal to or higher than the PV value.
[0091]
As can be seen from FIG. 13, the nanotopography of the wafer polished with the wafer holding disk of Example 1 is improved as compared with the wafer polished with the wafer holding disk of Comparative Example 1. When polished with the wafer holding disk of Example 1, the PV value of most areas in the wafer surface was 20 nm or less, which proved to be a preferable wafer.
[0092]
As shown in Table 1, under the polishing conditions of the present invention, the maximum PV value of nanotopography was about 28 nm when polished with the wafer holding disk of Example 1, and the wafer holding disk of Comparative Example 1 Compared to about 51 nm when polished with JIS, it is halved.
[0093]
[Table 1]

[0094]
(Comparative Example 2)
The polishing pressure for surface polishing is 200 g / cm. ² Wafer polishing pressure is 200 g / cm ² A wafer holding disk was prepared in the same manner as in Comparative Example 1 except that the wafer was polished, and the wafer was polished in the same manner.
[0095]
In the wafer holding disk of this comparative example, the amount around the suction hole was smaller than that of the wafer holding disk of Comparative Example 1. However, when the wafer was polished with the wafer holding plate of this comparative example, as shown in Table 1, the maximum PV value of nanotopography was not so improved as 42 nm.
[0096]
From the results of this comparative example, it was found that the nanotopography tends to be improved as the polishing pressure for surface polishing is lowered, but it is not sufficient to control the pressure for surface polishing.
[0097]
(Example 2)
The polishing pressure of surface grinding is 200 g / cm without filling the suction holes of the wafer holding base with a filler. ² A wafer holding plate was produced in the same manner as in Example 1 except that.
[0098]
As a result of observing the shape in the vicinity of the suction hole of the produced wafer holder, a slight dripping was observed, but the periphery of the suction hole was almost flat.
[0099]
In addition, the wafer was polished using the produced wafer holder. Wafer polishing conditions were the same as when the wafer was polished using the wafer holding disk of Example 1 (wafer polishing pressure = 400 g / cm). ² ).
[0100]
That is, in this example, the polishing pressure for surface polishing is set to the wafer polishing pressure (400 g / cm 2). ² ) Half (200 g / cm ² ).
[0101]
When a wafer holding disk was produced under such conditions and polished using this, as shown in Table 1, the maximum PV value of the wafer nanotopography was 29 nm, and the polishing pressure for surface polishing was 200 g. / Cm ² Wafer polishing pressure is 200 g / cm ² It was found that this was improved as compared with Comparative Example 2.
[0102]
In general, it is thought that deterioration in the vicinity of the suction holes can be prevented by reducing the absolute polishing pressure for surface polishing. However, this is not enough, and polishing during surface polishing is not enough to improve nanotopography. It can be seen that the relationship between the pressure and the polishing pressure of the wafer is important.
[0103]
(Comparative Example 3)
The polishing pressure for surface polishing is 400 g / cm. ² Wafer polishing pressure is 200 g / cm ² A wafer holding disk was produced in the same manner as in Comparative Example 1 except that the wafer was polished in the same manner. That is, the polishing pressure for surface polishing (400 g / cm ² ) Wafer polishing pressure (200 g / cm ² ).
[0104]
As a result of observing the shape in the vicinity of the suction hole of the manufactured wafer holder, the periphery of the suction hole was in a range of about 0.5 to 1 mm as in Comparative Example 1.
[0105]
After the wafer was polished using the produced wafer holder, nanotopography of the wafer surface was evaluated. When polished using the wafer holder of this comparative example, as shown in Table 1, the maximum PV value of the wafer nanotopography was 39 nm.
[0106]
From this measurement result, it was found that although the polishing pressure of the wafer was low, the deterioration of nanotopography was slightly improved but not sufficient.
[0107]
(Example 3)
The chamfering process was carried out by changing the polishing pressure of the chamfering polishing in two stages in a state where the suction hole of the wafer holder base was not filled with the filler. That is, the surface polishing of the wafer holding base is first performed with a polishing pressure equivalent to the wafer polishing pressure (400 g / cm in this embodiment). ² And then the polishing pressure is 200 g / cm ² The wafer holding disc was manufactured by lowering the thickness to 1 mm.
[0108]
Next, the wafer was subjected to a polishing process using the produced wafer holding plate. The wafer polishing conditions were the same as in Example 1 (polishing pressure 400 g / cm ² ).
[0109]
As a result of observing the shape in the vicinity of the suction hole of the produced wafer holder, a slight dripping was observed, but the periphery of the suction hole was almost flat.
[0110]
When the wafer was polished using the produced wafer holder, as shown in Table 1, the maximum PV value of the wafer nanotopography was as good as 27 nm.
[0111]
From this measurement result, it is conceivable that the final polishing pressure of the surface polishing has a particular influence on the nanotopography of the wafer when the wafer holding plate substrate is subjected to surface polishing.
[0112]
Thus, even if the suction holes are not filled with a filler, the nanotopography can be improved to some extent by considering the relationship between the polishing pressure at the time of surface polishing and the polishing pressure of the wafer. In this case, when controlling only by the polishing pressure at the time of surface polishing and the polishing pressure of the wafer, there is an advantage that it can be easily carried out because there are few steps.
[0113]
(Example 4)
An example in which the polishing pressure for surface polishing is lower than the wafer polishing pressure in a state where the suction holes are filled with a filler will be described.
[0114]
The suction hole of the wafer holder base is previously filled with the same filler as in Example 1, and the polishing pressure at the surface polishing is lower than the polishing pressure of the wafer as in Example 3 (300 g / in this example). cm ² And a wafer holder was produced. Also in this case, the periphery of the suction hole was almost flat, and the same effect was obtained while maintaining the suction hole (diameter 0.25 mm) as it was.
[0115]
When the wafer was polished using the produced wafer holder under the same conditions as in Example 1, as shown in Table 1, the maximum PV value of the wafer nanotopography was about 25 nm, which was a good surface state. It was.
[0116]
When controlling only by the polishing pressure at the time of surface polishing and the polishing pressure of the wafer, there are advantages that it is easy to carry out because there are few processes, but preliminary experiments such as how much each polishing pressure should be done, etc. May be necessary. Also, when polishing the wafer or the holding surface of the wafer holding disk, it may be preferable if the polishing pressure is high because the polishing ability is high. Therefore, the nanotopography is surely not affected by such high pressure conditions or other polishing conditions. In order to improve this, it is preferable to use filling with a filler. If surface filling polishing is performed after filling with a filler, it is possible to easily form a good wafer holding surface of a wafer holding plate with little influence of polishing conditions and the like.
[0117]
The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.
[0118]
For example, in this embodiment, the polishing pressure for polishing the product is 400 g / cm. ² However, the polishing pressure and other polishing conditions are arbitrary. Under the conditions of currently used polishing equipment and abrasives, the polishing pressure for chamfering is 100 to 300 g / cm. ² The wafer polishing pressure is about 200 to 500 g / cm. ² The degree is preferred. Further, it is not always necessary to include the lapping process of the chamfering process. In the case of filling the filler in the form of the present embodiment, it is performed before the lapping process (for example, sub-step 102b in FIG. 2). It may be carried out before 102c.
[0119]
In addition, the above-described chamfering process of the wafer holding plate is usually performed before the wafer is polished, but as the wafer is polished, the polishing cloth may change over time. It is possible to redo the chamfering process. Also in this case, it is preferable to apply the method for manufacturing a wafer holding plate of the present invention.
[0120]
【The invention's effect】
As described above, according to the present invention, a polishing wafer holding disk having a highly accurate wafer holding surface is provided. Therefore, if a wafer is polished using a polishing apparatus equipped with this wafer holding plate, a wafer having excellent flatness and a surface without waviness can be produced. In particular, when the wafer is a semiconductor wafer polished using the polishing wafer holder of the present invention, the nanotopography is improved, and it is possible to reduce polishing defects in CMP in a highly integrated device process. In addition, the yield of highly integrated devices can be improved.
[Brief description of the drawings]
FIG. 1 is an explanatory view schematically showing the order of steps of a first embodiment of a method for producing a wafer holding disc of the present invention.
FIG. 2 is a flowchart showing a process sequence of a first aspect of a method for manufacturing a wafer holding plate of the present invention.
FIG. 3 is an explanatory view schematically showing the order of steps of a second aspect of the method for manufacturing a wafer holding plate of the present invention.
FIG. 4 is a flowchart showing a process sequence of a second aspect of the method for manufacturing a wafer holding plate of the present invention.
FIG. 5 is a flowchart showing a process sequence according to a third aspect of the method for manufacturing a wafer holding plate of the present invention.
FIG. 6 is a flowchart showing a process sequence according to a fourth aspect of the method for manufacturing a wafer holding plate of the present invention.
FIG. 7 is a flowchart showing a process sequence according to a fifth aspect of the method for manufacturing a wafer holding plate of the present invention.
FIG. 8 is a flowchart showing a process sequence of the wafer polishing method of the present invention.
FIG. 9 is a schematic explanatory view showing an example of a wafer polishing apparatus used in the wafer polishing method of the present invention.
10 is a schematic explanatory view showing a state where the wafer is not held by the wafer polishing apparatus shown in FIG. 9; FIG.
FIG. 11 is a plan view showing an example of a wafer holding surface of a wafer holding disk manufactured by the method for manufacturing a wafer holding disk of the present invention.
12 is a graph showing a change in shape in the vicinity of the suction hole of the wafer holding disk manufactured in Example 1 and Comparative Example 1. FIG.
13 is a graph showing nanotopography of wafers polished in Example 1 and Comparative Example 1. FIG.
[Explanation of symbols]
10: Polishing device, 12: Surface plate, 12a: Polishing cloth, 14: Polishing head, 14a: Rotating shaft, 16: Abrasive supply pipe, 16a: Polishing agent, 18: Rotating shaft, 20: Back plate, 22: Outside Cover: 24: Vacuum part, 28: Suction path, 30: Wafer holding board, 30A: Wafer holding board base, 30a: Wafer holding board body, 30b: Resin film, 31: Pressurizing part, 32: Suction hole, 32a: Adsorption hole main body, 32b: Adsorption hole portion, 33: Pressurized air supply path, 34a: Wafer holding surface main body, 34b: Wafer holding surface, 36: Filler, W: Wafer.

Claims (13)

  A method of manufacturing a wafer holding disk capable of vacuum suction holding the wafer on a wafer holding surface when polishing the wafer, wherein the wafer holding surface body of the wafer holding disk body having a number of suction hole bodies is made of resin. A step of forming a wafer holding base having a plurality of suction holes by covering the resin film with a suction hole portion that is covered with a film to make the surface of the resin film a wafer holding surface and communicated with the suction hole body; The wafer holding surface of the wafer holding substrate is filled with a filler, the resin film is polished, the wafer holding surface is chamfered, and the wafer holding surface is adjusted. A method for producing a wafer holding disk characterized by the above.   A method of manufacturing a wafer holding disk capable of vacuum suction holding the wafer on a wafer holding surface when polishing the wafer, wherein the wafer holding surface body of the wafer holding disk body having a number of suction hole bodies is made of resin. A step of forming a wafer holding base having a plurality of suction holes by covering the resin film with a suction hole portion that is covered with a film to make the surface of the resin film a wafer holding surface and communicated with the suction hole body; A step of polishing the resin film at a pressure lower than the polishing pressure at the time of polishing the wafer, performing a chamfering process on the wafer holding surface, and adjusting the wafer holding surface. A method for manufacturing a wafer holding disk. 3. The method for manufacturing a wafer holder according to claim 2, wherein the polishing pressure is set to 300 g / cm ² (30 kPa) or less when the resin film of the wafer holder is polished.   A method of manufacturing a wafer holding disk capable of vacuum suction holding the wafer on a wafer holding surface when polishing the wafer, wherein the wafer holding surface body of the wafer holding disk body having a number of suction hole bodies is made of resin. A step of forming a wafer holding base having a plurality of suction holes by covering the resin film with a suction hole portion that is covered with a film to make the surface of the resin film a wafer holding surface and communicated with the suction hole body; The surface of the wafer holding surface is formed by polishing the resin film at a pressure equal to or lower than the polishing pressure when polishing the wafer while filling the suction holes of the wafer holding disk substrate with a filler. And a step of adjusting the wafer holding surface, and a method for producing a wafer holding disk.   A method of manufacturing a wafer holding disk capable of vacuum suction holding the wafer on a wafer holding surface when polishing the wafer, wherein the wafer holding surface body of the wafer holding disk body having a number of suction hole bodies is made of resin. A step of forming a wafer holding base having a plurality of suction holes by covering the resin film with a suction hole portion that is covered with a film to make the surface of the resin film a wafer holding surface and communicated with the suction hole body; The wafer holding surface is adjusted by polishing the resin film at a pressure equal to or lower than the polishing pressure at the time of polishing the wafer, and adjusting the wafer holding surface. A method for producing a wafer holding plate, comprising polishing the resin film of the plate while changing the polishing pressure to at least two stages.   A method of manufacturing a wafer holding disk capable of vacuum suction holding the wafer on a wafer holding surface when polishing the wafer, wherein the wafer holding surface body of the wafer holding disk body having a number of suction hole bodies is made of resin. A step of forming a wafer holding base having a plurality of suction holes by covering the resin film with a suction hole portion that is covered with a film to make the surface of the resin film a wafer holding surface and communicated with the suction hole body; The surface of the wafer holding surface is formed by polishing the resin film at a pressure equal to or lower than the polishing pressure when polishing the wafer while filling the suction holes of the wafer holding disk substrate with a filler. And adjusting the wafer holding surface, and polishing the resin film of the wafer holding disk by changing the polishing pressure in at least two stages. The method for manufacturing a wafer holding plate according to claim. By using a polishing apparatus for polishing a wafer polished according to any one of the wafer holding plate according to claim 1-6, characterized in that performing surfacing processing of the wafer holding surface by performing the resin film Manufacturing method. Performs lapping with free abrasive grains, and then the wafer according to any one of claims 1-7, characterized in that performing surfacing processing of the wafer holding surface by performing polishing of the resin film A method for producing a holding plate. 9. The resin constituting the resin film is one selected from the group consisting of an epoxy resin, an unsaturated polyester resin, a urethane resin, and a phenol resin. 9. Method for manufacturing a wafer holding plate. The method for manufacturing a wafer holder according to any one of claims 1 to 9 , wherein the resin film has a thickness of 0.1 to 3 mm. The method for manufacturing a wafer holder according to any one of claims 1 to 10 , wherein a hole diameter of the suction hole main body is 0.1 to 0.3 mm. Forming a resin film having the adsorption hole by forming a thermosetting resin film on the wafer holding surface main body of the wafer holding disk main body and then mechanically forming the adsorption hole in the resin film; claim 1-11 any one wafer holding plate of a manufacturing method according to feature. A back surface of a wafer is used as a wafer holding surface of the wafer holding disk using a polishing apparatus comprising a wafer holding disk and a polishing cloth manufactured by the method for manufacturing a wafer holding disk according to any one of claims 1 to 12. A method of polishing a wafer, wherein the wafer is brought into contact with the polishing cloth and the surface of the wafer is polished.

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