JP2004223636A - Polishing method, polishing device, polishing simulation method, and semiconductor device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve polishing quality by reducing unevenness of a step eliminating property and polishing unevenness of a circumferential direction in CMP polishing. <P>SOLUTION: In this polishing method, a polishing object is polished by making a polishing body perform a relative motion in relation to the polishing object, while pressing the polishing body on the polishing object. In the method, polishing steps on a plurality of polishing conditions different one another are provided. The unevenness of the step eliminating property is reduced by canceling and reducing the size of deviation of a history of relative speed of the relative motion generated by polishing on one polishing condition of the plurality of polishing conditions by deviation of a history of the relative speed generated by polishing on other one or more polishing conditions of the plurality of polishing conditions. The polishing unevenness of the circumferential direction is reduced by making an oscillation period of an oscillating motion of the polishing body and a rotation period of the polishing object asynchronous. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

この第一と第二の条件でＣｕ層を残膜厚０．４μｍまで研磨したところ、Ｓｉウェハ１３の任意の１点の相対速度の履歴の偏りが低減され、それによって段差解消性のムラをやや低減することができた。
［実施例２］
本実施例では図１４に示されるような格子パターンが全面に設けられた８インチＳｉウェハ１３を、図２で示される研磨装置を用い、以下の、異なる第一と第二の研磨条件で段差解消の為の研磨を行なった。格子パターンは３ｍｍ×２ｍｍであり、厚みが１．０μｍのＣｕ層が１００μｍピッチ、２００μｍ周期の格子状に、段差０．５μｍで配列されていた。
【００９７】

上記研磨条件で、初めに第一の研磨条件で、次に第二の研磨条件で、累計６０秒研磨を行なった。
【００９８】
この第一と第二の条件での研磨によって、Ｓｉウェハ１３の任意の１点の相対速度の履歴が偏りを持たなくなり、均等研磨が実現できた。その結果、Ｃｕ層の残膜厚を０．４μｍまで研磨したところ、パターンの凸部の段差のＳｉウェハ１３面全面に於けるムラ（段差の最大値と最小値との差）は０．０５μｍであった。
【００９９】
以上のように、本実施例により段差解消性のムラを大幅に低減することができた。
［比較例１］
本実施例では図１４に示されるような格子パターンが全面に設けられた８インチＳｉウェハ１３を、図２で示される研磨装置を用い、以下の、一つの研磨条件で段差解消の為の研磨を行なった。格子パターンは３ｍｍ×２ｍｍであり、厚みが１．０μｍのＣｕ層が１００μｍピッチ、２００μｍ周期の格子状に、段差０．５μｍで配列されていた。
【０１００】

以上の研磨条件で研磨を行ったところ、Ｓｉウェハ１３の任意の１点の相対速度の履歴の偏りが大きく発生し、研磨後のパターン凸部の断面は、図９（ｂ）に示されるようなクサビ状に偏った形状をしており、その形状はＳｉウェハ１３内の位置によってばらついていた。
【０１０１】
本比較例による段差解消性のムラは大きかった。
［実施例３］
本実施例では、鏡面研磨された半導体ウェハ面上に全面にＣｕ層が１．０μｍ形成されたパターンが無い半導体ウェハ１３のＣｕ層を、図２で示される半導体ウェハ１３の径よりも小さい径の研磨パッド１１を具えた研磨装置を用い研磨する。
【０１０２】
先ず所望の研磨プロファイルを達成できる条件として以下の研磨条件を設定した。
【０１０３】

この研磨条件での研磨パッド１１の揺動周期Ｔ_Ｐは、前記の式 Ｔ_Ｐ＝２Ｌ／ｖに上記値を代入することにより求められ、４．０秒だった。又、半導体ウェハ１３の回転周期Ｔ_Ｗは、前記の式 Ｔ_Ｗ＝６０／Ｒ に上記値を代入することにより求められ、０．３秒だった。研磨パッド１１の揺動周期４．０秒と半導体ウェハ１３の回転周期０．３秒の同期周期Ｔはこの４．０秒と０．３秒との最小公倍数である１２．０秒となり、研磨時間６０秒よりも短かった。
【０１０４】
そこで、半導体ウェハ１３の回転速度Ｒを２００ｒｐｍから１９９ｒｐｍに微調整し、再度同期周期を計算した。
【０１０５】
この研磨条件での半導体ウェハ１３の回転周期Ｔ_Ｗは、始めの０．３秒から６０／１９９秒に変わり、研磨パッド１１の揺動周期４．０秒と半導体ウェハ１３の回転周期６０／１９９秒の同期周期Ｔはこの４．０秒と６０／１９９秒の最小公倍数である１２００秒となり、研磨時間６０秒よりも大幅に長くなった。
【０１０６】
以上の条件で研磨したところ、この研磨時間中に同期が起こらなかった。
【０１０７】
以上の条件で研磨後に、研磨量（研磨膜厚）を測定したところ、図１５中のａ）に示されるように、研磨量は半導体ウェハ１３の中心に対して対称になり、円周方向のムラは小さく、中心対称の研磨が可能であった。
［比較例２］
本実施例では、鏡面研磨された半導体ウェハ面上にＣｕ層が１．０μｍ形成されたパターンが無い半導体ウェハ１３のＣｕ層を、図２で示される半導体ウェハ１３の径よりも小さい径の研磨パッド１１を具えた研磨装置を用い、以下の研磨条件で研磨した。
【０１０８】

この研磨条件での研磨パッド１１の揺動周期Ｔ_Ｐは、前記の式 Ｔ_Ｐ＝２Ｌ／ｖに上記値を代入することにより求められ、４．０秒だった。又、半導体ウェハ１３の回転周期Ｔ_Ｗは、前記の式 Ｔ_Ｗ＝６０／Ｒ に上記値を代入することにより求められ、０．３秒だった。研磨パッド１１の揺動周期４．０秒と半導体ウェハ１３の回転周期０．３秒の同期周期Ｔはこの４．０秒と０．３秒との最小公倍数である１２．０秒となり、研磨時間６０秒よりも短かった。
【０１０９】
以上の条件で研磨後に、研磨量（研磨膜厚）を測定したところ、図１５中のｂ）に示されるように、半導体ウェハ１３の中心に対して対称にならず、傾いた研磨量となっていて、円周方向の研磨ムラが大きかった。
【０１１０】
【発明の効果】
本発明によれば、段差解消性のムラを低減することができる研磨方法を提供することができる。
【０１１１】
又、本発明によれば、円周方向の研磨ムラを低減することができる研磨方法を提供することができる。
【０１１２】
又、本発明によれば、段差解消性のムラを低減することができる研磨装置を提供することができる。
【０１１３】
又、本発明によれば、円周方向の研磨ムラを低減できる研磨シミュレーション方法を提供することができる。
【０１１４】
又、本発明によれば、低コストで高品質の半導体デバイスを製造することができる半導体デバイス製造方法を提供することができる。
【０１１５】
又、本発明によれば、低コストで高品質の半導体デバイスを提供することができる。
【図面の簡単な説明】
【図１】本発明の実施の形態の研磨方法に於ける相対速度の履歴の偏りの低減を説明する。
【図２】本発明の実施の形態の研磨装置、又は、本発明の実施の形態の研磨方法を説明する研磨装置を示す。
【図３】小径研磨装置を示す。
【図４】研磨シミュレーションの計算位置を示す。
【図５】シミュレーションされた、点（０，０）上の相対速度の履歴を示す。
【図６】シミュレーションされた、点（６０，０）上の相対速度の履歴を示す。
【図７】シミュレーションされた、点（１２０，０）上の相対速度の履歴を示す。
【図８】相対速度の履歴に偏りがある場合を示す。
【図９】相対速度の履歴に偏りがある場合の、研磨後の凸状パターンの断面形状を示す。
【図１０】従来の研磨装置を示す。
【図１１】従来の円周方向の研磨ムラの様子を示す。
【図１２】本発明の実施の形態の半導体デバイスの製造方法を示す。
【図１３】本発明の実施の形態のシミュレーション方法を示す。
【図１４】実施例で研磨対象の格子状パターン付きＳｉウェハを示す。
【図１５】実施例の研磨プロファイルを示す。
【図１６】本発明の実施の形態の研磨方法を説明する図である。
【符号の説明】
１ パターン１
２ パターン２
３ 計算点位置
４ 段差
５ 研磨体運動
６ 研磨対象物運動
７ 研磨対象物１３上の任意の点
１１ 研磨体（研磨パッド）
１２ 研磨定盤
１３ 研磨対象物（半導体ウェハ、Ｓｉウェハ）
１４ 研磨対象物保持部（ウェハホルダ）
１５ 研磨剤
１６ 研磨剤供給部
１７ 制御部
１８ 研磨工具
１９ 研磨体移動機構
２０ 研磨対象物移動機構
２１、２２ 制御信号[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a polishing method, a polishing apparatus, a polishing simulation method, a semiconductor device, and a semiconductor device manufacturing method for polishing an object to be polished such as a semiconductor wafer.
[0002]
[Prior art]
2. Description of the Related Art In a semiconductor device manufacturing process, a flattening technique of a semiconductor device is indispensable for embedding of a metal electrode, a multilayer wiring, and the like, and in the flattening technique, chemical mechanical polishing (Chemical Mechanical Polishing) is required. , Or Chemical Mechanical Planarization (hereinafter referred to as CMP) technology is of particular importance.
[0003]
Conventionally, CMP is performed using a CMP polishing apparatus as shown in FIG. In this conventional polishing apparatus, a semiconductor wafer 13 for manufacturing a semiconductor device is attached to a wafer holder 14, and a polishing body 11 having a diameter larger than the diameter of the semiconductor wafer 13 is attached to a surface plate 12 having substantially the same size. Have been. The semiconductor wafer 13 is pressed against the rotating polishing body 11 while the abrasive 15 is supplied, and the semiconductor wafer 13 is swung while rotating, whereby polishing is performed by physical action and chemical action. (For example, see Patent Document 1)
The above conventional CMP polishing apparatus requires an ever-larger platen 12 as the diameter of the semiconductor wafer becomes larger, so the apparatus itself becomes larger, and a large and expensive clean room space is required for installation. In addition to this, there is a problem that the operability of the apparatus is poor, as can be seen from the fact that replacement of consumable parts such as a polishing pad is very difficult due to its size. Also, in a film forming process of a semiconductor process, a film formed on a semiconductor wafer surface often has a film thickness distribution. In a CMP process, a desired polishing amount (removed by polishing) corresponds to the film thickness distribution. However, it is difficult to control the distribution of the polishing amount because the conventional CMP polishing apparatus polishes the semiconductor wafer by constantly bringing the semiconductor wafer into contact with a huge polishing body. For example, in order to have a polishing amount distribution, an extremely complicated and difficult means of locally adjusting a pressure distribution of an object to be polished against a polishing body on a semiconductor wafer surface can be considered, but this is difficult to implement. In addition, there is a problem that the controllability of the polishing amount distribution is insufficient.
[0004]
In order to solve the above problems of the conventional CMP polishing apparatus, a polishing apparatus (hereinafter, referred to as a small-diameter pad polishing apparatus) for polishing with a polishing body having a diameter smaller than the diameter of a semiconductor wafer as shown in FIG. 3 has been proposed. ing. In this small-diameter pad polishing apparatus, a semiconductor wafer 13 is attached to a wafer holder 14, and a polishing body 11 having a smaller diameter than the semiconductor wafer 13 is attached to a surface plate 12. Polishing is performed by pressing the polishing body 11 against the rotating semiconductor wafer 13 while supplying the polishing agent 15 and swinging while rotating the polishing body 11. (For example, see Patent Document 2)
This small-diameter pad polishing apparatus has an advantage that the polishing apparatus can be downsized because the polishing body 11 is small. In addition, the small-diameter pad polishing apparatus has good operability, as can be seen from the fact that since the apparatus is small, it is easy to replace consumable parts such as abrasive bodies.
[0005]
Furthermore, since the diameter of the polishing body is smaller in the small-diameter pad polishing apparatus than in the semiconductor wafer, the polishing amount distribution (polishing profile) can be freely controlled by changing the existence probability of the polishing body on the semiconductor wafer surface. It is.
[0006]
The small-diameter pad polishing apparatus appropriately combines the rotation speed of the semiconductor wafer 13 and the polishing body 11, the swing of the polishing body 11, and the like in order to obtain a uniform or desired removal amount distribution, that is, a polishing amount distribution, on the semiconductor wafer surface. Polishing is performed under polishing conditions.
[0007]
[Patent Document 1]
U.S. Pat. No. 3,615,955
[Patent Document 2]
JP-A-7-88759
[0008]
[Problems to be solved by the invention]
However, in recent years, the polishing quality required for the flattening technology has become increasingly higher. When polishing is performed with a small-diameter pad polishing apparatus as shown in FIG. There was a problem that there was unevenness. Specifically, the size of a step remaining after polishing a convex pattern on a semiconductor wafer surface depends on the pattern position or pattern orientation on the semiconductor wafer surface, and the remaining step is not uniform. was there. Because of the unevenness in the step-elimination capability, even if the optimal timing for step-elimination is found in one pattern at one position on the semiconductor wafer surface, another position on the semiconductor wafer surface is found at the same timing. In the case of a pattern having the same shape, it is not optimal timing due to, for example, insufficient step resolution or excessive polishing, or even if a pattern at the same position on the semiconductor wafer surface changes pattern direction, it is not optimal timing. There was a problem. For this reason, when there is unevenness in the elimination of the step, there is a problem that an accurate timing for eliminating the step of the convex pattern and ending the polishing cannot be found.
[0009]
In the polishing using a small-diameter pad polishing apparatus as shown in FIG. 3, the diameter of the polishing body 11 is smaller than the diameter of the polishing target 13, and the relative position of the polishing body 11 with respect to the center position of the rotating polishing target 13. Polishing is performed while changing the position by the swing of the polishing body 11. When polishing is performed with such a small-diameter pad polishing apparatus, polishing unevenness in the circumferential direction, that is, circumferential unevenness in the removed film thickness may occur. FIG. 11 shows how the polishing unevenness occurs. (1) to (6) are measurement positions for obtaining polishing unevenness (polishing amount distribution) on the surface of the semiconductor wafer 13. In the case where polishing unevenness occurs in the circumferential direction in this manner, even when the polishing is partially completed at the optimal timing for appropriate polishing completion, the remaining portion is insufficiently polished or the polishing amount is excessive, so that polishing is performed. The exact timing of the end could not be found.
[0010]
These problems of unevenness in eliminating steps and polishing unevenness in the circumferential direction have reduced the polishing quality.
[0011]
The present invention solves the above problems, and provides a polishing method, a polishing apparatus, a polishing simulation method that enables a polishing method with high polishing quality, and a method of manufacturing a semiconductor device that enables production of a high-quality semiconductor device. And a semiconductor device manufactured by the method of manufacturing a semiconductor device.
[0012]
[Means for solving the problem]
In order to solve the above-described problems, a first aspect of the present invention is to move the polishing body relative to the polishing object while pressing the polishing body against the polishing object, thereby polishing the polishing object. Polishing method, comprising the step of polishing under a plurality of different polishing conditions, the deviation of the history of the relative speed of the relative movement of the relative movement caused by polishing under one of the plurality of polishing conditions. The magnitude is offset by the bias of the history of the relative speed of the relative motion caused by polishing under one or more other polishing conditions of the plurality of polishing conditions.
[0013]
According to a second aspect of the present invention, in the first aspect, the polishing body and the object to be polished are each rotated during polishing, and the polishing is performed under one of the plurality of polishing conditions. The rotation direction of the body is reversed under another one of the plurality of polishing conditions.
[0014]
According to a third aspect of the present invention, in the first aspect, the polishing body and the object to be polished are respectively rotated during polishing, and the polishing is performed under one of the plurality of polishing conditions. The rotation directions of the body and the object to be polished are both reversed under another one of the plurality of polishing conditions.
[0015]
In a fourth aspect of the present invention, in any one of the first to third aspects, the polishing is performed by a polishing apparatus having a plurality of polishing positions, and each of the plurality of different polishing conditions is the plurality of polishing conditions. One of the plurality of polishing conditions is provided for each movement of the polishing body and the polishing object holding unit at each of the polishing positions, and one of the plurality of polishing conditions is provided at one of the plurality of polishing positions. After polishing is completed by the conditions, in order to perform polishing at another one of the plurality of polishing conditions at another one of the plurality of polishing positions, polishing is performed from the one polishing position. Transporting the object to be polished to another polishing position.
[0016]
A fifth aspect of the present invention includes a polishing body rotating mechanism for giving a rotating motion to the polishing body and a polishing object rotating mechanism for giving a rotating motion to the polishing object, while pressing the polishing body against the polishing object. A polishing apparatus for moving the polishing body relative to the polishing object to polish the polishing object, wherein the polishing body rotating mechanism and the polishing object rotating mechanism are clockwise and counterclockwise, respectively. By rotating one or both of the rotational direction of the rotational movement of the polishing body or the rotational direction of the rotational movement of the object to be polished during the polishing process, the relative rotation is configured to be rotatable in both directions. This is to reduce the bias of movement.
[0017]
A sixth aspect of the present invention is directed to polishing while changing the relative position of the polishing body with respect to the center position of the polishing object by swinging movement of the polishing body while pressing the polishing body against the rotating polishing object. In this polishing method, the swing cycle of the swing motion and the cycle of the rotary motion are not synchronized during the polishing time.
[0018]
A seventh aspect of the present invention is directed to polishing while changing the relative position of the polishing body with respect to the center position of the polishing object by swinging movement of the polishing body while pressing the polishing body against the rotating polishing object. This is a simulation method for determining the polishing conditions of the polishing apparatus to be performed, and the polishing conditions are determined in advance so that the oscillation cycle of the oscillation motion and the cycle of the rotation motion are not synchronized during the polishing time. .
[0019]
An eighth aspect of the present invention is a method for manufacturing a semiconductor device, comprising a step of polishing a polishing object using any one of the above-described aspects 1, 4, 5, and 6.
[0020]
A ninth aspect of the present invention is a semiconductor device manufactured according to the eighth aspect.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Before describing the polishing method of the present invention, the process leading to the present invention will be described in order to facilitate understanding of the present invention.
[Approach to the invention]
First, the inventor of the present invention has found that, because the amount of polishing is proportional to the relative speed of the polishing body with respect to the object to be polished, the small-diameter pad polishing apparatus shown in FIG. In order to obtain knowledge about the relative speed during polishing, a simulation calculation of the history of the relative speed was performed. Specifically, as shown in FIG. 4, three points (0, 0), (60, 0), and (120, 0) are arbitrarily selected on the surface of the semiconductor wafer 13 having a diameter of 12 inches. The history of the relative velocity V given to each point by the polishing body 11 was calculated by simulation. If the rotation cycle of the semiconductor wafer 13 and the oscillation cycle of the polishing body 11 are sufficiently shorter than the polishing time, and the rotation cycle and the oscillation cycle are not synchronized, any point on the circumference of the radius 60 Receives almost the same history of relative speed, and any point on the circumference of the radius 120 also receives substantially the same history of relative speed. Therefore, in the case of the above polishing conditions, the simulation calculation shows that, in addition to the three points (0, 0), (60, 0), and (120, 0), the relative velocities on the circumferences of the radius 60 and the radius 120 are different. You can almost know the history of V.
[0022]
Here, (0,0), (60,0), and (120,0) indicate positions on the surface of the semiconductor wafer 13 at the time T = 0 when the simulation is started. Things. Since the semiconductor wafer 13 rotates, the apparent coordinates of these three points change with the rotation of the semiconductor wafer 13 and the elapsed polishing time. The rotational angular velocity of the semiconductor wafer 13 is ω _W Then, for example, the coordinates of the point (120, 0) after T seconds are (120 cos ω) _W T, 120 sin ω _W T).
[0023]
In addition, the polishing body 11 performs a rotating motion and a swinging motion in which a center-to-center distance with the semiconductor wafer 13 periodically changes.
[0024]
Here, the speed due to the rotational movement of the above three points on the surface of the semiconductor wafer 13 is V _W The composite speed of the rotational speed and the oscillating speed of the polishing body 11 at the above three points is V _P Then, the relative speed V of the polishing body 11 with respect to the semiconductor wafer 13 is
V = V _P −V _W Given by
[0025]
In this simulation, in order to understand the relationship between the polishing amount and the relative speed in more detail, the relative speed V is converted into Vr which is a component in the radial direction (r) of the semiconductor wafer 13 and Vθ which is a component in the rotation direction (θ). The components were decomposed, and the state of each of the relative speed component Vr and the relative speed component Vθ was examined. Where | V | ² = | Vr | ² + | Vθ | ² There is a relationship. In the r direction, the direction outward from the center of the semiconductor wafer 13 was defined as positive, and in the θ direction, the clockwise direction was defined as positive.
[0026]
This simulation was performed under the conditions shown in Table 1 below.
[0027]
FIGS. 5, 6, and 7 show the simulation results of the relative velocities at the calculation points (0, 0), (60, 0), and (120, 0) on the surface of the semiconductor wafer 13, respectively. The sampling interval was set at 10 msec.
[0028]
The simulation results show the transition of the relative speed components Vr and Vθ with respect to the elapsed time when polishing is performed under the conditions shown in Table 1, that is, the history of the relative speed itself at each of the three calculation points on the relative speed.
[Table 1]
Effective diameter of polishing surface of polishing body 11: outer diameter 268 mmφ, inner diameter 84 mmφ (ring shape)
Rotation speed of polishing body 11: 200 rpm clockwise
Rotational speed of semiconductor wafer 13: 200 rpm counterclockwise
Swing stroke: 38mm
Swing speed: 40 mm / sec
The center-to-center distance between the center of the polishing body 11 and the center of the semiconductor wafer 13 at the start of polishing was 30 mm, and the polishing body 11 was swung within the range of 30 mm and 68 mm.
Calculation time: 10 seconds
And
[0029]
Referring to FIG. 5, Vr at the calculation point (0, 0) oscillates between the positive side and the negative side with time, and is equally positive and negative, that is, at the same frequency on the positive side and the negative side. And they are appearing in the same size.
[0030]
Now, in general, in order to quantify the history of the relative speed V given to the polishing object 13 by the polishing body 11 of the polishing apparatus as shown in FIG. 3, the relative speed V is integrated or integrated over the polishing time. The resulting vector is called the cumulative relative velocity, and V _S Indicated by This cumulative relative speed V _S Represents the deviation (vector value) of the history of the relative speed V. In addition, the relative velocity components Vr and Vθ are all integrated or integrated over the polishing time, and are referred to as cumulative relative velocity components. _S , Vθ _S Indicated by Cumulative relative speed component Vr _S Represents the bias of the history of the relative speed component Vr or the r-direction component of the bias of the history of the relative speed V. Also, the cumulative relative speed component Vθ _S Represents the bias of the history of the relative speed component Vθ or the θ-direction component of the bias of the history of the relative speed V.
[0031]
Returning to the examination of the simulation results, the cumulative relative speed Vr of the relative speed Vr at the calculation point (0, 0) _S Is substantially zero, it can be said that there is no bias in the history of the relative speed Vr.
[0032]
Referring to FIG. 5, Vθ at the calculation point (0, 0) also oscillates between the positive side and the negative side with time similarly to Vr, and is positive and negative equally, that is, positive and negative. Appear at the same frequency and size. Cumulative relative speed Vθ of this relative speed Vθ _S Since its magnitude is almost zero, it can be said that the history of the relative speed Vθ is not biased as well as the history of the relative speed Vr. Therefore, the polishing at the calculation point (0, 0) has no deviation in the history of the relative speeds Vr and Vθ, and can be said to be uniform polishing.
[0033]
Referring to FIG. 6, Vr at calculation point (60, 0) _S Appear equally positive and negative as Vr at the calculation point (0, 0). Cumulative relative speed Vr of this Vr _S Is almost zero, so there is no bias in the history of the relative speed Vr. However, Vθ shows a negatively biased appearance. Cumulative relative speed Vθ of this Vθ _S Is calculated, this cumulative relative speed Vθ _S Has a size that cannot be ignored in the negative direction. The history of the relative speed Vθ in FIG. _S have. In other words, the history of the relative speed V has a large deviation Vθ in the θ direction. _S have. Therefore, the polishing at the calculation point (60, 0) has a bias in the history of the relative speed, and can be said to be uneven polishing.
[0034]
Referring to FIG. 7, Vr at calculation point (120, 0) appears equally positive and negative as Vr at calculation point (0, 0). Cumulative relative speed Vr of this Vr _S Is almost zero, so there is no bias in the history of the relative speed Vr. However, Vθ appears to be more negatively biased than Vθ at the calculation point (60, 0). Cumulative relative speed Vθ of this Vθ _S Is calculated, this cumulative relative speed Vθ _S Is Vθ at the calculation point (60, 0) in the negative direction. _S It has a larger value. That is, the history of the relative velocity Vθ is larger than the deviation Vθ at the calculation point (60, 0). _S have. In other words, the history of the relative velocity V has a larger deviation Vθ in the θ direction than at the calculation point (60, 0). _S have. Therefore, the polishing at the calculation point (120, 0) has a bias in the relative speed, and it can be said that the polishing at the calculation point (60, 0) is more uneven than the polishing at the calculation point (60, 0).
[0035]
FIG. 8 shows a state in which there is a bias in the history of the relative speed, which has been found from the above simulation results. In FIG. 8, ● indicates the position 3 of the calculation point (120, 0), and arrows indicate the patterns 1 and 2 at the positions receiving the history of the relative velocity Vθ substantially equivalent to the calculation point (120, 0). Bias of the history of relative speed Vθ (accumulated relative speed Vθ _S ). Vθ _S Is negative, so it is facing counterclockwise. Vr history bias (cumulative relative speed Vr _S ) Are not shown because they are almost zero.
[0036]
Next, the semiconductor wafer 13 was actually polished under the polishing conditions shown in Table 1 in which it was found from the above simulation that the history of the relative speed had a bias. In FIG. 8, four rectangles, up, down, left, and right, are arranged at the same position in the r direction as the calculation point (120, 0), and show the device pattern of the semiconductor wafer actually polished. In FIG. 8, the upper pattern 1 and the left pattern 2 are arranged on substantially the same circumference. The pattern 1 has its longitudinal direction oriented in the r direction, and the pattern 2 has its longitudinal direction oriented in the θ direction. ing. Polishing in the pattern 1 has no deviation in the history of the relative speed in the longitudinal direction (r direction), but the deviation in the history of the relative speed Vθ in the perpendicular direction (θ direction). _S There is. In addition, the polishing in the pattern 2 is such that the deviation of the history of the relative speed in the longitudinal direction (θ direction) is Vθ. _S However, there is no deviation in the history of the relative speed in the direction perpendicular to the direction (r direction).
[0037]
FIG. 9A shows the deviation Vθ of the history of the relative speed in the direction AA ′ of the cross section in the longitudinal direction of the pattern 2 and the direction. _S Is the deviation Vr of the history of the relative speed in the direction BB ′ of the cross section in the longitudinal direction of the pattern 1 and the direction. _S Is shown. Vr _S Is almost zero, and therefore is indicated by a circle.
[0038]
FIG. 9B shows the shape of the AA ′ cross section of the pattern 2 before (left) and after polishing (right) and the shape of the BB ′ cross section of the pattern 1 before (left) and after polishing. The shape of (right) is shown.
[0039]
The AA ′ cross section of the pattern 2 is greatly affected by the relative velocity being deviated in the AA ′ direction, and as shown in the upper part of FIG. 9B, the step is greatly inclined with the progress of polishing. The step is reduced while having a tendency.
[0040]
On the other hand, since the relative speed is uniformly generated in the BB 'direction in the BB' section in the BB 'direction, as shown in the lower part of FIG. Steps are reduced.
[0041]
From the above facts, it has been clarified that, depending on the difference in the orientation of the pattern arrangement on the surface of the semiconductor wafer 13, even if the pattern structure is the same, there is a great difference in how the steps are eliminated.
[0042]
At the same time, it has been clarified that a pattern placed in a direction in which the accumulated relative velocity component is small can be subjected to step-eliminating polishing with a small inclination in that direction.
[0043]
This led to the idea that it is effective to reduce the deviation of the history of the relative speed in order to improve the elimination of the step.
[Embodiment 1 of the present invention]
The polishing method according to the first embodiment of the present invention will be described with reference to FIGS.
[0044]
In the polishing method according to the embodiment of the present invention, in FIG. 2, the polishing body 11 is pressed against the polishing target 13 while the polishing body 11 having a diameter smaller than the polishing target 13 is pressed against the polishing target 13. A polishing method for polishing the object to be polished 13 by relative movement with respect to the polishing object, comprising a step of polishing under a plurality of different polishing conditions, and polishing under any one of the plurality of polishing conditions. Also, the history of the relative speed of the relative motion has a bias, and the magnitude of the bias is reduced by polishing under the plurality of polishing conditions.
[0045]
The relative movement of the polishing method according to the embodiment of the present invention is given by the movements 5 and 6 of the polishing body 11 and the object 13 to be polished. The polishing body 11 is provided with the polishing body movement 5 by the polishing body moving mechanism 19, and the polishing object 13 is provided with the polishing object movement 6 by the polishing object moving mechanism 20. The polishing body motion is usually a combination of a rotation motion and a swing motion as shown in the polishing apparatus of FIG. 2 or only the rotation motion, and the polishing object motion is usually only the rotation motion. In particular, the exercise is not limited to the exercise shown in FIG. The relative motion is a polishing body motion 5 with respect to a polishing object motion 6.
[0046]
The relative speed V of the polishing method according to the embodiment of the present invention is the speed of the polishing body motion 5 of the polishing body 11 with respect to the speed of the polishing object motion 6 of the polishing object 13. _P And the speed of the polishing object 13 is V _W Then, the relative velocity V becomes V = V in exactly the same way as the definition made in the [Approach to the Invention] section. _P -V _W Given by
[0047]
The polishing method according to the embodiment of the present invention performs polishing under a plurality of different polishing conditions. At least among the plurality of polishing conditions, the histories of the relative speeds are different from each other. The histories of the relative speeds different from each other are given by the polished body motion or the polished object motion different from each other between the respective polishing conditions.
[0048]
In the polishing method according to the embodiment of the present invention, the history of each relative speed has one bias (vector) under one polishing condition. The deviation has a different direction and magnitude between the plurality of different polishing conditions. When the bias is combined between these different polishing conditions, the combined bias is smaller than the bias under one polishing condition. That is, the bias of the history of the relative speed generated under one polishing condition is offset by the bias of the history of the relative speed generated under another polishing condition, and the magnitude of the bias resulting from the cancellation is the one polishing condition. Other polishing conditions are set so as to be smaller than the deviation generated in the above. Other polishing conditions may be one or more and may be any number.
[0049]
When the polishing method according to the embodiment of the present invention as described above is performed, the deviation of the history of the relative speed of the polishing body 11 is reduced, and therefore, the convex pattern on the surface of the polishing target 13 such as a semiconductor wafer is polished. Sometimes, the step can be reduced uniformly on the pattern irrespective of the direction of the pattern, and the step can be reduced uniformly regardless of the position of the pattern on the polishing target 13.
[0050]
The polishing method according to the embodiment of the present invention described above will be specifically described with reference to FIGS. 1 (a) and 1 (b), reference numeral 13 denotes an object to be polished attached to the object to be polished 14 of the polishing apparatus shown in FIG. The upper convex pattern 7 indicated by ● is an arbitrary point on the polishing target 13.
[0051]
A point on a concentric circle whose radius is the distance of the arbitrary point 7 from the center of the polishing object 13 generally receives an equivalent polishing history (a history of relative speed). The polishing performed by the polishing body 11 on the pattern 1 elongated in the r direction and the pattern 2 elongated in the θ direction on the concentric circles will be described.
[0052]
The relative speed of the polishing body 11 under the first polishing condition is defined as V1, and the r component of the bias of the history of the relative speed V1 after the polishing under the first polishing condition is V1r. _S , Θ component as V1θ _S And V1θ _S Has a size that cannot be ignored, and is indicated by an arrow in FIG. _S Since is usually substantially zero, it is not shown in FIG. After the polishing under the first polishing condition is completed, the polishing is performed at the relative speed V2 of the polishing body 11 under the second polishing condition. The r component of the bias of the history of the relative speed V2 is V2r _S , Θ component as V2θ _S Then, V2θ _S Is V1θ as shown by the arrow in FIG. _S V1θ in the opposite direction _S Occurs to offset the magnitude of V2r _S Is V1r _S As shown in FIG. 1 (a), it is usually substantially zero, as shown in FIG. As a result, as shown in FIG. _S Is smaller than the deviation due to polishing under the single first or second polishing condition. Where Vθ _S = V1θ _S + V2θ _S It is.
[0053]
As described above, since the bias of the history of the relative speed V is reduced, the step can be reduced uniformly regardless of the direction of the pattern and the position of the pattern on the polishing target.
[0054]
Specifically, the deviation of the history of the relative speed V of the polishing body can be reduced by, for example, the following method.
[0055]
In the first method, the first polishing condition is such that the polishing body 11 is polished for a predetermined time while rotating the polishing object 11 at a certain rotation speed in a certain rotation direction and the polishing object 13 at a certain rotation speed in a certain rotation direction. The second polishing condition is such that only the rotation direction of the polishing body 11 is rotated in the reverse direction to the first polishing condition, and the other conditions are the same as the first polishing condition.
[0056]
According to this method, the bias of the history of the relative speed caused by the polishing under the first polishing condition cannot be completely offset by the bias caused by the polishing under the second polishing condition. Can be greatly reduced.
[0057]
In the second method, the first polishing condition is such that the polishing body 11 is polished for a predetermined time while rotating the polishing body 11 at a certain rotation speed in a certain rotation direction and the polishing object 13 at a certain rotation speed in a certain rotation direction. The second polishing condition is a condition in which the rotation direction of the polishing body 11 and the rotation direction of the polishing target 13 are both reversed without changing the magnitude of the rotation speed, and the polishing is performed for the same time as the first polishing condition. Things.
[0058]
According to this method, it is possible to completely offset the deviation of the history of the relative speed caused by the polishing under the first polishing condition by the deviation caused by the polishing under the second polishing condition. By this method, it is possible to perform substantially uniform polishing and ideal polishing in which the deviation of the history of the relative speed of the polishing body 11 is zero.
[0059]
The third method is, as shown in FIG. 16, a method of polishing using a polishing apparatus having a first polishing position, a second polishing position, and, if necessary, a third and subsequent polishing positions. Each of the plurality of polishing positions is provided with a polishing body and a polishing object holding portion. The movement conditions such as the rotation of each polishing body and each polishing object holding part are set differently from the movement conditions of other polishing bodies and other polishing objects, and the first polishing position is the first polishing position of the polishing body. A motion condition that causes a bias in the history of one relative speed is set, and a motion condition that offsets the bias caused by the first polishing condition is set at the second polishing position. For example, the relationship between the first polishing condition and the second polishing condition is the method described in the first method or the second method.
[0060]
In the third method, first, when the polishing of the object to be polished is completed at the first polishing position under the first polishing condition, the object to be polished is transferred to the second polishing position (in FIG. (Indicating the conveying direction), and polishing is performed at the second polishing position under the second polishing condition. According to the polishing method of the present embodiment, the deviation of the history of the relative velocity generated at the first polishing position can be reduced by the deviation generated at the second polishing position. Also, while polishing the first polishing object under the second polishing condition at the second polishing position, the second polishing object can be polished under the first polishing condition at the first polishing position. Polishing time can be shortened and the production volume is large. Further, since one polishing condition may be set at one polishing position, different polishing conditions can be easily set.
[0061]
The polishing method according to the embodiment of the present invention exerts its effect particularly when the diameter of the polishing body 11 is smaller than the diameter of the polishing target 13, but the diameter of the polishing body 11 is equal to or larger than the diameter of the polishing target 13. It is sometimes effective.
[0062]
FIG. 2 shows a polishing apparatus according to an embodiment of the present invention. A polishing apparatus according to an embodiment of the present invention will be described with reference to FIG. The polishing apparatus according to the embodiment of the present invention includes a polishing body 11, a polishing platen 12 on which the polishing body 11 is attached, a polishing object holder 14, and a rotational movement (direction is indicated by an arrow) of the polishing body 11. A polishing body moving mechanism 19 for giving a swinging motion (direction is indicated by an arrow), a polishing object moving mechanism 20 for giving a rotating motion to the polishing object 13, a polishing body moving mechanism 19 and a polishing object moving mechanism 20; And a control unit 17 for sending control signals 21 and 22 to control these operations.
[0063]
Here, the polishing body moving mechanism 19 of the polishing apparatus according to the embodiment of the present invention includes an actuator (not shown) such as a motor for giving the above-described rotational movement, the above-mentioned swinging movement, and the like to the polishing body 11, and controls the same. And a drive unit (not shown) including an input / output unit for receiving the signal 21 and causing the actuator to perform a desired drive. The polishing body moving mechanism 19 is configured to be able to rotate the polishing body 11 in either a clockwise direction or a counterclockwise direction.
[0064]
The polishing object moving mechanism 20 includes an actuator (not shown) such as a motor for giving the above-described rotational movement to the polishing object 13, and a control signal 22 for causing the actuator to perform desired driving. A drive unit (not shown) including an input / output unit.
Further, the polishing object moving mechanism 20 of the polishing apparatus according to the embodiment of the present invention is configured so that the rotation of the polishing object 13 can be rotated clockwise or counterclockwise.
[0065]
Polishing is performed by pressing the polishing body 11 against the rotating polishing object 13 while supplying the polishing agent 15 and swinging while rotating the polishing body 11.
[0066]
The control unit 17 of the polishing apparatus according to the embodiment of the present invention can set a plurality of different polishing conditions. At the time of polishing, the control unit 17 sends control signals 21 and 22 as follows.
[0067]
In the first stage of polishing, the control unit 17 sends the control signal 21 to the polishing body moving mechanism 19 and the control signal 22 to the object to be polished in accordance with the first polishing condition among a plurality of mutually different polishing conditions. It is sent to the object moving mechanism 20. Upon receiving the control signal 21, the polishing body moving mechanism 19 causes the polishing body 11 to perform the first polishing body movement 5, and receives the control signal 22, and the polishing target moving mechanism 20 causes the polishing target 13 to perform the first polishing. The object movement 6 is performed. A first relative speed is generated in the polishing body 11 in response to these movements 5 and 6, and a first deviation occurs in the history of the relative speed of the polishing body 11.
[0068]
The controller 17 sends a second control signal 21 to the polishing body moving mechanism 19 and a second control signal in the second stage of polishing, in accordance with a second polishing condition among a plurality of different polishing conditions. The control signal 22 is sent to the polishing object moving mechanism 20. Upon receiving the second control signal 21, the polishing body moving mechanism 19 causes the polishing body 11 to perform the second polishing body movement 5, and upon receiving the second control signal 22, the polishing object moving mechanism 20 causes the polishing object moving mechanism 20 to perform polishing. 13 causes the second object to be polished 6 to move. A second relative speed is generated in the polishing body 11 corresponding to these movements 5 and 6, and a second deviation occurs in the history of the relative speed of the polishing body 11.
[0069]
In the polishing apparatus according to the embodiment of the present invention, the second deviation cancels the first deviation, and the magnitude of the canceled deviation is smaller than the magnitude of the first or second deviation. When polishing is performed under three or more different polishing conditions, the first deviation is offset by the second deviation and the third deviation, etc., and the magnitude of the deviation resulting from the offset is the first or second deviation. Or, the magnitude of the third deviation is reduced.
[0070]
In other words, in the polishing apparatus according to the embodiment of the present invention, the bias of the history of the relative speed caused by the polishing under each of the plurality of different polishing conditions is determined by a plurality of different polishing conditions. By synthesizing the polishing under the polishing conditions, the magnitude of the deviation generated under each polishing condition is reduced.
[0071]
As described above, according to the polishing method and the polishing apparatus according to the embodiment of the present invention, by applying a plurality of different polishing conditions, the deviation Vr of the history of the relative speed generated under one polishing condition. _S , Vθ _S Is reduced, so that unevenness in removing the step of the pattern on the semiconductor wafer surface is reduced. That is, according to the polishing method and the polishing apparatus of the embodiment of the present invention, the steps can be reduced uniformly regardless of the direction of the pattern and the position of the pattern on the polishing target.
[0072]
As described above, the case where the history of the r component Vr of the relative speed V has substantially no bias has been described. However, it is needless to say that the present invention can be applied to the case where the history of Vr has a bias.
[Embodiment 2 of the present invention]
A polishing method according to an embodiment of the present invention will be described using the polishing apparatus shown in FIG.
[0073]
Using the polishing apparatus shown in FIG. 2 in which the diameter of the polishing body 11 is smaller than the diameter of the polishing object 13, the relative position of the polishing body 11 with respect to the center position of the rotating polishing object 13 is changed. The point that the polishing is performed while being changed by the dynamic motion is the same as the conventional polishing method.
[0074]
In the polishing method according to the embodiment of the present invention, the oscillation cycle of the oscillation motion and the rotation cycle of the rotational motion of the object to be polished are not synchronized during the polishing time. More precisely, the polishing conditions are set so as to avoid synchronization during the polishing time. More specifically, in the polishing method according to the embodiment of the present invention, when a polishing time is represented by t, a synchronization cycle between the oscillation cycle of the oscillation motion and the rotation cycle of the rotation motion of the polishing target is set. The swing cycle and the rotation cycle are set so that T is longer than the polishing time t.
[0075]
More specifically, assuming that the average speed (scalar) of the rocking motion is v (mm / sec) and the stroke of the rocking motion is L (mm), the rocking cycle T _P (Seconds)
Equation T _P = 2L / v. If the rotation speed of the rotation is Rrpm, the rotation period T _W (Seconds) is given by the formula T _W = 60 / R.
[0076]
At this time, T _P And T _W T, which is the least common multiple of _P And rotation cycle T _W Is a period of synchronization. For example, T _P For 0.9 seconds, T _W Is 10 seconds, the synchronization period T is 90 seconds, which is the least common multiple.
[0077]
If the time 90 seconds is longer than the desired polishing time t, the rotation cycle and the swing cycle are adopted as they are. If the time 90 seconds is equal to or shorter than the desired polishing time t, the rotational speed of the polishing body 11 or the swinging stroke of the polishing target 13 or the average speed of the swinging motion of the polishing object 13 is adjusted to increase or decrease T. _P Or T _W Is adjusted so that the synchronization period T exceeds the polishing time t.
[0078]
As described above, according to the polishing method of the embodiment of the present invention, since the oscillation cycle of the oscillation motion and the rotation cycle of the rotational motion of the object are asynchronous, the circle of the object to be polished is Polishing unevenness in the circumferential direction (rotational direction) can be significantly reduced.
[0079]
The simulation method according to the embodiment of the present invention is described below with reference to FIG. 13, and is a simulation method performed in advance to determine the polishing conditions of the polishing apparatus as shown in FIG.
[0080]
First, in step S1, polishing conditions for a desired polishing profile (polishing amount distribution) are acquired.
[0081]
Next, in step S2, a swing cycle of the polishing body, a rotation cycle of the object to be polished with respect to the above-mentioned polishing conditions, and a synchronization cycle between the swing cycle and the rotation cycle are obtained.
[0082]
Next, in step S3, it is determined whether the synchronization period T is longer than the polishing time t. If the synchronization period T is longer than the polishing time t, the process proceeds to step S5; otherwise, the process proceeds to step S4.
[0083]
Next, in step S4, the swing condition of the polishing body or the rotation condition of the object to be polished are finely adjusted, and the process proceeds to step S2.
[0084]
Finally, in step S5, the determined polishing conditions including the swing condition and the rotation condition are output.
[0085]
According to the simulation method of the present embodiment, when polishing under the polishing conditions simulated by this method, the swing motion of the polishing body and the rotation motion of the polishing target are not synchronized, so that polishing unevenness in the circumferential direction, That is, the polishing amount distribution is small, and a centrally symmetric polishing amount distribution is obtained.
[Embodiment 3 of the present invention]
FIG. 12 is a flowchart showing a semiconductor device manufacturing process according to the embodiment of the present invention. After starting the semiconductor device manufacturing process, first, in step S200, an appropriate processing step is selected from the following steps S201 to S204. According to the selection, the process proceeds to any of steps S201 to S204.
[0086]
Step S201 is an oxidation step of oxidizing the surface of the semiconductor wafer. Step S202 is a CVD step of forming an insulating film on the surface of the semiconductor wafer by CVD or the like. Step S203 is an electrode forming step of forming an electrode film on the semiconductor wafer by a process such as vapor deposition. Step S204 is an ion implantation step of implanting ions into the semiconductor wafer.
[0087]
After the CVD process or the electrode forming process, the process proceeds to step S209, and it is determined whether the CMP process is performed. If not, the process proceeds to step S206; otherwise, the process proceeds to step S205. Step S205 is a CMP step, in which the polishing method or the polishing apparatus of the present invention is used to flatten an interlayer insulating film or to form a damascene by polishing a metal film on the surface of a semiconductor device. Done.
[0088]
After the CMP step or the oxidation step, the process proceeds to step S206. Step S206 is a photolithography process. In the photolithography process, a resist is applied to a semiconductor wafer, a circuit pattern is printed on the semiconductor wafer by exposure using an exposure device, and the exposed semiconductor wafer is developed. Further, the next step S207 is an etching step of removing portions other than the developed resist image by etching, removing the resist, and removing unnecessary resist after etching.
[0089]
Next, it is determined in step S208 whether all necessary steps have been completed. If not, the process returns to step S200, and the previous steps are repeated to form a circuit pattern on the semiconductor wafer. If it is determined in step S208 that all steps have been completed, the process ends.
[0090]
In the semiconductor device manufacturing method according to the embodiment of the present invention, since the polishing method or the polishing apparatus of the present invention is used in the CMP step, the direction of the convex pattern of the semiconductor wafer and the pattern Irrespective of the position at the step, the steps remaining in the polished pattern can be made uniform. Alternatively, the polishing unevenness in the circumferential direction, that is, the polishing amount distribution can be reduced. Therefore, in the semiconductor device manufacturing method according to the embodiment of the present invention, the timing at which the step is eliminated by polishing or the timing at which a desired polishing amount is reached can be accurately grasped, and the yield in the CMP process is improved, and the polishing is performed. Semiconductor wafers, and ultimately, the semiconductor device manufacturing quality can be improved. As a result, there is an effect that a high-quality semiconductor device can be manufactured at a lower cost than the conventional semiconductor device manufacturing method.
[0091]
Note that the polishing apparatus according to the embodiment of the present invention may be used in a CMP step of a semiconductor device manufacturing process other than the semiconductor device manufacturing process described above.
[0092]
The semiconductor device according to the embodiment of the present invention is manufactured by the semiconductor device manufacturing method according to the embodiment of the present invention. As a result, the semiconductor device according to the embodiment of the present invention has the effect of lower cost and higher quality than the conventional semiconductor device.
[0093]
Although the first to third embodiments of the present invention have been described above, the present invention is not limited to these embodiments.
[0094]
For example, the above embodiment is an example applied to CMP, but the present invention can also be applied to polishing of optical members such as glass.
[0095]
【Example】
[Example 1]
In this embodiment, an 8-inch Si wafer 13 having a lattice pattern as shown in FIG. 14 provided on the entire surface thereof is stepped under different first and second polishing conditions using the polishing apparatus shown in FIG. Polishing for the solution was performed. The lattice pattern was 3 mm × 2 mm, and a Cu layer having a thickness of 1.0 μm was arranged in a lattice shape having a pitch of 100 μm and a period of 200 μm with a step of 0.5 μm.
[0096]

When the Cu layer is polished to a residual film thickness of 0.4 μm under the first and second conditions, the deviation of the history of the relative speed at an arbitrary point on the Si wafer 13 is reduced, thereby reducing the unevenness in eliminating the step. Slightly reduced.
[Example 2]
In this embodiment, an 8-inch Si wafer 13 having a lattice pattern as shown in FIG. 14 provided on the entire surface thereof is stepped under different first and second polishing conditions using the polishing apparatus shown in FIG. Polishing for the solution was performed. The lattice pattern was 3 mm × 2 mm, and a Cu layer having a thickness of 1.0 μm was arranged in a lattice shape having a pitch of 100 μm and a period of 200 μm with a step of 0.5 μm.
[0097]

Under the above polishing conditions, polishing was first performed under the first polishing condition and then under the second polishing condition for a total of 60 seconds.
[0098]
By the polishing under the first and second conditions, the history of the relative speed at any one point of the Si wafer 13 has no bias, and uniform polishing can be realized. As a result, when the remaining film thickness of the Cu layer was polished to 0.4 μm, the unevenness (the difference between the maximum value and the minimum value of the step) of the step of the projection on the entire surface of the Si wafer 13 was 0.05 μm. Met.
[0099]
As described above, according to the present embodiment, the unevenness of the step elimination property can be significantly reduced.
[Comparative Example 1]
In this embodiment, an 8-inch Si wafer 13 provided with a lattice pattern as shown in FIG. 14 over its entire surface is polished by the polishing apparatus shown in FIG. Was performed. The lattice pattern was 3 mm × 2 mm, and a Cu layer having a thickness of 1.0 μm was arranged in a lattice shape having a pitch of 100 μm and a period of 200 μm with a step of 0.5 μm.
[0100]

When the polishing was performed under the above polishing conditions, the deviation of the relative speed history at an arbitrary point on the Si wafer 13 was greatly generated, and the cross section of the pattern convex portion after polishing was as shown in FIG. 9B. The shape was uneven in a wedge shape, and the shape varied depending on the position in the Si wafer 13.
[0101]
The unevenness in eliminating the step according to this comparative example was large.
[Example 3]
In the present embodiment, the Cu layer of the semiconductor wafer 13 having no pattern in which the Cu layer is formed on the entire surface of the mirror-polished semiconductor wafer by 1.0 μm is formed with a diameter smaller than the diameter of the semiconductor wafer 13 shown in FIG. Is polished using a polishing apparatus provided with the polishing pad 11 of FIG.
[0102]
First, the following polishing conditions were set as conditions for achieving a desired polishing profile.
[0103]

The swing cycle T of the polishing pad 11 under these polishing conditions _P Is given by the formula T _P = 2 L / v, which was determined to be 4.0 seconds. Also, the rotation cycle T of the semiconductor wafer 13 _W Is given by the formula T _W = 60 / R was determined by substituting the above value, which was 0.3 seconds. The synchronization cycle T between the oscillation cycle of the polishing pad 11 of 4.0 seconds and the rotation cycle of the semiconductor wafer 13 of 0.3 seconds is 12.0 seconds which is the least common multiple of the 4.0 seconds and 0.3 seconds. The time was shorter than 60 seconds.
[0104]
Therefore, the rotation speed R of the semiconductor wafer 13 was finely adjusted from 200 rpm to 199 rpm, and the synchronization cycle was calculated again.
[0105]
Rotation cycle T of semiconductor wafer 13 under these polishing conditions _W Is changed from the initial 0.3 seconds to 60/199 seconds, and the synchronization period T of 4.0 seconds of the oscillation period of the polishing pad 11 and 60/199 seconds of the rotation period of the semiconductor wafer 13 is 4.0 seconds and 60 seconds. It was 1200 seconds, which was the least common multiple of / 199 seconds, and was much longer than the polishing time of 60 seconds.
[0106]
When the polishing was performed under the above conditions, no synchronization occurred during the polishing time.
[0107]
When the polishing amount (polishing film thickness) was measured after polishing under the above conditions, the polishing amount became symmetric with respect to the center of the semiconductor wafer 13 as shown in a) of FIG. Unevenness was small, and center-symmetric polishing was possible.
[Comparative Example 2]
In the present embodiment, the Cu layer of the semiconductor wafer 13 having no pattern in which the Cu layer is formed to 1.0 μm on the mirror-polished semiconductor wafer surface is polished to a diameter smaller than the diameter of the semiconductor wafer 13 shown in FIG. Polishing was performed under the following polishing conditions using a polishing apparatus having a pad 11.
[0108]

The swing cycle T of the polishing pad 11 under these polishing conditions _P Is given by the formula T _P = 2 L / v, which was determined to be 4.0 seconds. Also, the rotation cycle T of the semiconductor wafer 13 _W Is given by the formula T _W = 60 / R was determined by substituting the above value, which was 0.3 seconds. The synchronization cycle T between the oscillation cycle of the polishing pad 11 of 4.0 seconds and the rotation cycle of the semiconductor wafer 13 of 0.3 seconds is 12.0 seconds which is the least common multiple of the 4.0 seconds and 0.3 seconds. The time was shorter than 60 seconds.
[0109]
After the polishing under the above conditions, the polishing amount (polishing film thickness) was measured. As shown in b) of FIG. 15, the polishing amount was not symmetrical with respect to the center of the semiconductor wafer 13 but was inclined. And uneven polishing in the circumferential direction was large.
[0110]
【The invention's effect】
According to the present invention, it is possible to provide a polishing method capable of reducing unevenness in eliminating steps.
[0111]
Further, according to the present invention, it is possible to provide a polishing method capable of reducing polishing unevenness in a circumferential direction.
[0112]
Further, according to the present invention, it is possible to provide a polishing apparatus capable of reducing unevenness in eliminating steps.
[0113]
Further, according to the present invention, it is possible to provide a polishing simulation method capable of reducing polishing unevenness in a circumferential direction.
[0114]
Further, according to the present invention, it is possible to provide a semiconductor device manufacturing method capable of manufacturing a high quality semiconductor device at low cost.
[0115]
Further, according to the present invention, a high-quality semiconductor device can be provided at low cost.
[Brief description of the drawings]
FIG. 1 illustrates the reduction of bias in the history of relative speed in a polishing method according to an embodiment of the present invention.
FIG. 2 illustrates a polishing apparatus according to an embodiment of the present invention or a polishing apparatus illustrating a polishing method according to an embodiment of the present invention.
FIG. 3 shows a small-diameter polishing apparatus.
FIG. 4 shows calculation positions of a polishing simulation.
FIG. 5 shows the simulated history of the relative speed at point (0,0).
FIG. 6 shows the simulated history of the relative velocity at point (60,0).
FIG. 7 shows a simulated history of the relative velocity at point (120,0).
FIG. 8 shows a case where the history of the relative speed is biased.
FIG. 9 shows a cross-sectional shape of a convex pattern after polishing when there is a bias in the history of relative speed.
FIG. 10 shows a conventional polishing apparatus.
FIG. 11 shows a conventional state of uneven polishing in the circumferential direction.
FIG. 12 shows a method for manufacturing a semiconductor device according to an embodiment of the present invention.
FIG. 13 shows a simulation method according to the embodiment of the present invention.
FIG. 14 shows an Si wafer with a grid pattern to be polished in an example.
FIG. 15 shows a polishing profile of an example.
FIG. 16 is a diagram illustrating a polishing method according to an embodiment of the present invention.
[Explanation of symbols]
1 Pattern 1
2 pattern 2
3 Calculation point position
4 steps
5 Abrasive body exercise
6 Object movement
7. Arbitrary point on the polishing object 13
11 polishing body (polishing pad)
12 Polishing surface plate
13 Object to be polished (semiconductor wafer, Si wafer)
14 Polishing object holder (wafer holder)
15 abrasive
16 Abrasive supply section
17 Control part
18 polishing tools
19 Abrasive moving mechanism
20 Polishing object moving mechanism
21, 22 control signal

Claims (9)

A polishing method for polishing the polishing object while pressing the polishing object against the polishing object while relatively moving the polishing object with respect to the polishing object, and polishing the polishing object under a plurality of different polishing conditions. The magnitude of the deviation of the history of the relative speed of the relative motion caused by polishing under one of the plurality of polishing conditions is determined by using at least one of the other polishing conditions among the plurality of polishing conditions. A polishing method characterized in that the reduction is offset by a bias in the history of the relative speed of the relative motion caused by polishing under the polishing conditions. The polishing body and the object to be polished are each rotated during polishing, and the direction of rotation of the polishing body under one of the plurality of polishing conditions is the other of the plurality of polishing conditions. The polishing method according to claim 1, wherein the polishing is performed under two polishing conditions. The polishing body and the object to be polished are each rotated during polishing, and the rotation direction of the polishing body and the object to be polished in one of the plurality of polishing conditions is the rotation direction of the plurality of polishing conditions. 2. The polishing method according to claim 1, wherein both are reversed under another one of the polishing conditions. The polishing is performed by a polishing apparatus having a plurality of polishing positions, and each of the plurality of different polishing conditions is determined with respect to each movement of the polishing body and the polishing object holder at each polishing position of the plurality of polishing positions. Given, after polishing is completed by one of the plurality of polishing conditions at one of the plurality of polishing positions, at another one of the plurality of polishing positions. The method according to claim 1, further comprising the step of: transporting the object to be polished from the one polishing position to another polishing position in order to perform polishing under another one of the plurality of polishing conditions. The polishing method according to any one of claims 1 to 3. A polishing body rotating mechanism for giving a rotating motion to the polishing body and a polishing object rotating mechanism for giving a rotating motion to the polishing object, wherein the polishing body is pressed against the polishing object while the polishing body is pressed against the polishing object. Relative to the polishing object to polish the object to be polished, wherein the polishing body rotation mechanism and the object to be polished are rotatable in both clockwise and counterclockwise directions. The method is characterized in that one or both of the rotational direction of the rotational movement of the polishing body and / or the rotational direction of the rotational movement of the object to be polished are reversed during the polishing to reduce the bias of the relative movement. Polishing equipment. A polishing method for polishing while changing a relative position of the polishing body with respect to a center position of the polishing object by swinging movement of the polishing body while pressing the polishing body against a rotating polishing object. A polishing method, wherein the oscillation cycle of the dynamic motion and the cycle of the rotary motion are not synchronized during the polishing time. While pressing the polishing body against the rotating polishing object, the polishing condition of the polishing apparatus for performing polishing while changing the relative position of the polishing body with respect to the center position of the polishing object by the swinging motion of the polishing body is determined. A polishing simulation method for determining polishing conditions in advance so that the oscillation cycle of the oscillation motion and the cycle of the rotation motion are not synchronized during the polishing time. A method for manufacturing a semiconductor device, comprising a step of polishing an object to be polished using the polishing method according to any one of claims 1 to 4 and claim 6 or the polishing apparatus according to claim 5. A semiconductor device manufactured by the semiconductor device manufacturing method according to claim 8.

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