201236811 六、發明說明： C 明戶斤屬·=δ^ 軒々貝3 發明領域 圓等之工作件進行研 本發明係有關於一種將半導體晶 削加工之研削裝置。 t ^tT ϋ 發明背景 JL 〇 半導體元件之製造製程中，為了得到半導體元件之 的厚度’在為多數之半導體元件之集合體之工作件的階段 中，進行將該内面研削、研磨後薄化。又，隨著近來半導 體元件之顯著的薄型化，工作件變成要更進一步地薄化加 -般而言’工作件之研削或研磨係—面心該厚度一 =行。本發明之中請人提案—種使被加Μ接觸測定用 探針，正確地測量工作件之厚度，研削成所期望的厚度之 研削裝置（參照專利文獻丨）。 又 先行技術文獻 專利文獻 【專利文獻1】日本專利公開公報特開第2〇〇〇 6〇丨8號公 報 【^明内】 發明概要 發明欲解決之課題 201236811 然而，根據上述之研削裝置，當例如埋入到樹脂之Cu 枉因為研削樹脂而露出時等進行預定之構件露出時，由於 埋入有該構件之高度未必是固定的，因此有時候即使將工 作件研削成一定的厚度後也會無法適當地使該構件露出。 本發明係有鑑於上述課題而做成者，其目的在於提供 一種可高精確度地進行預定之構件之露出的研削裝置。 為解決上述課題、達成目的，本發明之研削裝置係具 有：形成有用以保持工作件之保持面之保持機構、將保持 於該保持機構之工作件進行研削加工之加工機構、及控制 該加工機構之動作之控制機構，前述工作件係由反射率為 第一反射率之第一構件、與被覆該第一構件且反射率為第 二反射率之第二構件所構成，該控制機構具有檢測部，該 檢測部係將檢測光照射於研削中之前述工作件之被研削 面，並接收來自被研削面之反射光，根據該檢測部所檢測 出之受光量，判斷為被該第二構件覆蓋之該第一構件有露 出時，則停止前述工作件之研削。 發明效果 根據本發明之研削裝置，可高精確度地進行預定之構 件之露出。 圖式簡單說明 第1圖係顯示本發明之一實施形態之研削裝置之構成 的立體圖。 第2圖係顯示本發明之一實施形態之研削裝置之構成 的側面圖。 4 201236811 第3圖係_ + 1 不本發明之一實施形態之研削裝置之檢測 部之構成的模式圖。 第4圖係3苞- 不本發明之一實施形態之工作件w之構成 的模式圖。 第5圖係_ $ 士 & 卞本發明之一實施形態之檢測處理之流程 的流程圖。 第6圖係用d 乂說明本發明之一實施形態之檢測處理者。 第7圖係用以 乂说明本發明之一實施形態之檢測處理者。 第8圖係用^ . 乂說明本發明之一實施形態之檢測處理者。 第9圖係_ + 士政αη 下本發明之一實施形態之工作件W之變形 例之構成的模式圖。 【實施冷式】 較佳實施例之詳細說明 以下參照圖式說明本發明之一實施形態之研削裝置 之構成及其動作。再者，本發明並*受限於1¾實施形態。 〔研削裝置之構成〕 ,首先’參照第1〜3圖’說明本發明之一實施形態之研 肖!裝置的構成。第i圖係顯示本發明之一實施形態之研削裝 置之構成的立體圖，第2圖係顯示本發明之—實施形態之研 削裝置之構成的側面圖。第3圖係顯示本發明之—實施形態 之研削裝置之檢測部之構成的模式圖。 如第1圖所示’本發明之一實施形態之研削裝幻具有 立方體之基。基台2之上面的前方側設有可接收對研削 裝置1之純g之操作面板3。彳㈣面板3讀方側設有支 201236811 持失頭台41之台支持座4。台支持座4之後方側設有支柱部 5。支柱部5之前面支持了可朝上下方向移動之研削單元6。 研削單it 6的附近設有用以檢測構成保持於失頭台4丄之工 作件w之構件的檢測部70。控制部(控制機構)c控制·統合 該等各構成部。 工作件勤配設於基板上之2種構件構成，且構成為第 -構件埋人第二構件。構成卫作件w之構件並無特別限 定，例如第-構件可例示為Cu、第二構件可例示成型樹脂 等。基板並無特別限定，可例示如石夕晶圓、碟石申化鋼錄晶 圓、碳化石夕晶圓等之半導體晶圓、陶£基板、玻璃基板、 藍寶石基板之無機材料基板等。 台支持座4係設置成正方形’可旋轉地支持夾頭台4卜 台支持座4連接於未圖示之簡機構，且藉由該驅動機構供 給之驅動力’可在形成於基台2之上面之開口部㈣朝前後 方向滑動。藉此，夾頭台41可在使研削單元6與卫作件〜之 露出面相對向之研縣置、魅該研削位置朝前方側離 開’供給加工前之工作件W，另一方面回收加工後之工作 件w之載置更換位置之間滑動。台支持座4之前後設有防塵 蓋8,防塵蓋係可抑制王作_在研削加工時產生之研磨塊 之碎屑等進入基台2内。防塵蓋8構成為，安裝於台支持座* 之前面及後面’並且設置成可因應於台支持座4之移動位置 而伸縮’並且覆蓋基台2之開口部2a。 夾頭台41係構成本發明之保持機構者，且形成圓盤 狀’並於上面形成保持朝圖中箭頭A所示之方向搬入之工作 6 201236811 件W之保持面41a。保持面—之中央部分係藉由多孔陶究 材形成吸附面。_台41連接於配置於基台2内之未圖示之 吸引源’並且在保持面4la之吸附面上吸附保持工作件W。 又失頭口 41連接於未圖示之旋轉驅動機構，藉由該旋轉 驅動機構可在將工作切㈣於健面仏之㈣下旋轉。 #支柱部5設置成立方體，且於其前面在失頭台41之上面 设有使研肖彳單元6移動之·單元移動機構5卜研削單元移 動機構51具有可藉由滾珠_式之移動機構相對於支枉部 5朝上下方向移動。 轴口 52經由安農於其前面側之支持部53而支持研削 單元6。 研肖]單tl6係構成本發明之加卫機構者，並具有研削輪 61 ’研削輪61係'可自由㈣地安裝於未圖示之活塞的下 1。該研肖彳輪61係由例如將鑽石之研磨粒以金屬鍵結或樹 接《等、、，。合劑固定之鑽石磨粒所構成。研削單元6係使研 磨塊61朝與夾頭台41之旋轉方向相同之方向旋轉，並且使 研f塊61抵接於配置在研削位置之卫作件W之表面，藉此 將路出於工作件|表面之構件進行研削加工。 ，欢則。[WG具有.1；立設置於基台2之開口部以之側方側 • ^之U7卜及设置於臂部71之前端之雷射頭部72。 ^第2圖所示’檢測㈣由雷射頭部72將雷射光照射於工作 之表面，並接收在卫作件^^之表面反射之雷射光。 人雷射碩^72如第3圖所示，具有：殼體η卜分離壁η2、 光源與鏡片之之照射系統723、及連接於控制部c之感 201236811 測器724 ’由殼體721與分離壁722所包圍之空間，將設置於 忒體721之側面之給水口 725所供給之水由設置於殼體721 下面之排水口 726供給到工作件w之表面，並且照射系統 723於工作件~之表面照射雷射光，並在感測器724接收反 射光。接著’控制部C根據反射光之受光量之變化而檢測露 出於工作件W表面之構件。 統合控制以上所構成之研削裝置1之各構成部之動作 的控制部C係由内設有用以保存研削裝置丨之動作所需要的 各種資料之記憶體的微電腦等所構成。在該控制部C之控制 之下，研削裝置1執行以下所說明之檢測處理。 〔檢測處理〕 如第3圖所示’檢測部7〇之雷射頭部72對隨著夾頭台41 之旋轉而旋轉之工作件W之被研削面，照射作為檢測光之 雷射光’並且接收反射光。如此之處理係因應於工作件w 之構成而適當地變更工作件w(夾頭台41)距離旋轉軸l的距 離來決定檢測之路徑而進行。 以下，參照第4圖及第5圖，說明本實施形態之檢測處 理手績。第4圖係例示作為本實施形態之檢測對象之工作件 ^的模式圖’第5圖係顯示檢測處理手續之流程圖。 如第4圖所示，工作件w係由配設於基板上之2種構件 構成，並構成為第一構件埋入第二構件。例如作為第一構 件之Cu之晶片配設於基板上，並由作為第二構件之成型樹 脂所被覆。 若研削此種工作件W之第二構件而第一構件露出時， 8 201236811 則進行本實施形態之檢測處理。例如，使工作件w(夾頭台 41)旋轉並在第4圖中箭頭B所示之路徑進行檢測處理時，撿 測部會周期性地接收來自第—構件之反射光與來自第 二構件之反'射光。其中，由於在第―構件之反射率愈在第 二構件之反射率不同，因此反射光之強度會有週期性的變 化。 另-方面，若是因第二構件之研削不足而第一構件未 露出時，或第-構件之露出不㈣，即使在相同路徑進行 檢測處理，反射光之強度也不會變化。因此，可藉反射光 之強度已經變化，判斷第一構件之露出已足夠。曰 如第5圖所示之流程圖係操作者操作操作面板3，並於 示執行檢測處理之時_為開始，檢測處理進人步驟^ 處理。 ㈣81之處理中，控制部C控制檢測部7〇之動作， 對隨者夾頭台41之旋轉而旋轉之工作件㈣射雷射光並且 接收反射光’㈣將受光量記憶於記憶體。藉此，步驟^ 之處理完成，檢測處理進入步驟§2之處理。 步驟S2之處理中，控制部c在步驟^確認已記憶之 量’並判斷變化之有無。若未變化(步驟Μ，N。），則 為第-構件之露出不^(步驟S3)，續行工作件％之研 驟糾，並返回步驟S1。另—方面4有變化(步驟s2,2 則利斷為第一構件之露出已完成(步驟S5),並控制研削 6,分::作:W之研削(步驟S6),結束一連串的檢測處理。 在此，參昭 ’、、、弟6圖〜弟8圖，具體的說明判斷受光量之 201236811 變化有無的方法。第6圖〜第8圖係例示第4圖之工作件W在 第4圖之箭頭B所示之路徑中，測量已接收之反射光之強度 資料’益計算出資料之移動平均値的結果。第6圖係關於因 第二構件之研削不足而第一構件無法露出之工作件W，第7 圖係關於第二構件之研削不足而第一構件之露出不足之工 作件W ,第8圖係關於研削第二構件後第一構件已充分霧出 之工作件W。 例如第4圖之工作件w，藉反射光之強度資料之移動平 均値超過預定界定値來判斷前述步驟82之受光量有變化， 則可判斷為第-構件之露出已足夠。關於臨界值係先根據 第構件、第二構件之反射率來設定《如此，第6圖、第7 圖中由於移動平均値低於界定値，因此續行研削。第8圖 中’由於移動平均數高於臨界值，因此停止研削。 本實施形態之研削處理亦可適用於如第9圖所示之由 第$件構成之基板埋入第二構件之工作件w。此種工作 田第構件露出時，在上述步驟S1中，在圖中箭頭C 不之路徑進行檢測之受光量會固^。因此，上述步驟S2 之及2光之強度資料超過預先根據第-構件、第二構件 光量有變臨界值而變化時，則判斷為反射光之受 2化並且第一構件業已露出。 理，檢測據本發明之1施形態之檢測處 來檢測埋入第:!件與第二構件之反射率的不同 地進行預定構件之露出，因此可高精確度 201236811 【圖式簡單說明3 第1圖係顯示本發明之一實施形態之研削裝置之構成 的立體圖。 第2圖係顯示本發明之一實施形態之研削裝置之構成 的側面圖。 第3圖係顯示本發明之一實施形態之研削裝置之檢測 部之構成的模式圖。 第4圖係顯示本發明之一實施形態之工作件W之構成 的模式圖。 第5圖係顯示本發明之一實施形態之檢測處理之流程 的流程圖。 第6圖係用以說明本發明之一實施形態之檢測處理者。 第7圖係用以說明本發明之一實施形態之檢測處理者。 第8圖係用以說明本發明之一實施形態之檢測處理者。 第9圖係顯示本發明之一實施形態之工作件W之變形 例之構成的模式圖。 【主要元件符號說明】 1.. .研削裝置 W...工作件 6…研削單元 C...控制部 41.. .夾頭台 70.. .檢測部201236811 VI. Description of the invention: C Minghujin·=δ^ Xuanbeibei 3 Field of the Invention Research on a workpiece such as a circle The present invention relates to a grinding device for crystallizing a semiconductor. BACKGROUND OF THE INVENTION JL 〇 In the manufacturing process of a semiconductor element, in order to obtain the thickness of the semiconductor element, the inner surface is ground, polished, and thinned at the stage of working for a plurality of semiconductor element assemblies. Moreover, with the recent significant thinning of the semiconductor elements, the workpiece becomes to be further thinned and the thickness of the workpiece is generally reduced. In the present invention, a grinding device for measuring the thickness of the workpiece and measuring the thickness of the workpiece to the desired thickness (see Patent Document 丨) is proposed. [Patent Document 1] Japanese Patent Laid-Open Publication No. JP-A No. Hei. No. 2, No. 6, No. 2, the entire disclosure of the present invention is hereby incorporated by reference. For example, when Cu 枉 embedded in a resin is exposed when the resin is exposed, the predetermined member is exposed, since the height of the member embedded therein is not necessarily fixed, sometimes even if the workpiece is ground to a certain thickness, The member cannot be properly exposed. The present invention has been made in view of the above problems, and it is an object of the invention to provide a grinding device capable of exposing a predetermined member with high precision. In order to solve the above problems and achieve the object, the grinding device of the present invention has a holding mechanism for forming a holding surface for holding a workpiece, a processing mechanism for grinding a workpiece held by the holding mechanism, and controlling the processing mechanism. In the control mechanism of the operation, the working member is composed of a first member having a reflectance of a first reflectance and a second member covering the first member and having a second reflectivity, the control mechanism having a detecting portion The detecting unit irradiates the detection light to the ground surface of the workpiece in the grinding, receives the reflected light from the ground surface, and determines that the light is detected by the detecting unit to be covered by the second member. When the first member is exposed, the grinding of the workpiece is stopped. EFFECT OF THE INVENTION According to the grinding apparatus of the present invention, the exposure of the predetermined member can be performed with high precision. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing the configuration of a grinding device according to an embodiment of the present invention. Fig. 2 is a side view showing the configuration of a grinding device according to an embodiment of the present invention. 4 201236811 Fig. 3 is a schematic view showing a configuration of a detecting portion of a grinding device according to an embodiment of the present invention. Fig. 4 is a schematic view showing the configuration of a workpiece w which is not an embodiment of the present invention. Fig. 5 is a flow chart showing the flow of the detection processing of an embodiment of the present invention. Fig. 6 is a view showing the detection processor of an embodiment of the present invention by d 乂. Figure 7 is a diagram for explaining a detection processor of an embodiment of the present invention. Fig. 8 is a view showing a detection processor of an embodiment of the present invention. Fig. 9 is a schematic view showing a configuration of a modification of the workpiece W according to an embodiment of the present invention. [Implementation of the cold type] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the configuration and operation of the grinding apparatus according to an embodiment of the present invention will be described with reference to the drawings. Furthermore, the present invention is limited to the embodiment. [Configuration of the grinding device] First, the configuration of the device of the embodiment of the present invention will be described with reference to Figs. 1 to 3 . Fig. i is a perspective view showing a configuration of a grinding device according to an embodiment of the present invention, and Fig. 2 is a side view showing a configuration of a grinding device according to an embodiment of the present invention. Fig. 3 is a schematic view showing the configuration of a detecting portion of the grinding device according to the embodiment of the present invention. As shown in Fig. 1, the grinding device of one embodiment of the present invention has a cube base. The front side of the upper surface of the base 2 is provided with an operation panel 3 which can receive the pure g of the grinding device 1.彳 (4) Panel 3 read side side support 201236811 Hold head of the lost platform 41 support 4. A pillar portion 5 is provided on the rear side of the table support base 4. The front surface of the pillar portion 5 supports the grinding unit 6 that is movable in the vertical direction. In the vicinity of the grinding unit itself 6, a detecting unit 70 for detecting a member constituting the workpiece w held by the head stand 4 is provided. The control unit (control unit) c controls and integrates the components. The working piece is configured by two types of members disposed on the substrate, and is configured such that the first member is buried in the second member. The member constituting the sanitary member w is not particularly limited. For example, the first member may be exemplified as Cu, and the second member may be exemplified by a molding resin. The substrate is not particularly limited, and examples thereof include a semiconductor wafer such as a stone wafer, a disc stone, a carbon crystal wafer, a ceramic substrate, a glass substrate, and an inorganic material substrate of a sapphire substrate. The table support base 4 is provided in a square shape rotatably supporting the chuck table 4, and the support base 4 is connected to a simple mechanism (not shown), and the driving force supplied by the drive mechanism can be formed on the base 2 The upper opening (4) slides in the front-rear direction. Thereby, the chuck table 41 can be placed between the grinding unit 6 and the exposed surface of the guarding member, and the grinding position can be separated from the grinding position toward the front side, and the workpiece W before the processing is supplied. The rear work piece w is slid between the placement and replacement positions. A dustproof cover 8 is provided in front of and behind the support base 4, and the dustproof cover can suppress the entry of the grinding block of the grinding block generated during the grinding process into the base 2. The dustproof cover 8 is configured to be attached to the front surface and the rear surface of the table support base* and is provided to be expandable and contractible in accordance with the moving position of the table support base 4 and to cover the opening portion 2a of the base 2. The chuck table 41 constitutes a holding mechanism of the present invention, and is formed in a disk shape, and a holding surface 41a for holding the workpiece 6 in the direction indicated by the arrow A in the figure is formed thereon. The central part of the holding surface forms an adsorption surface by a porous ceramic material. The table 41 is connected to a suction source (not shown) disposed in the base 2 and sucks and holds the workpiece W on the adsorption surface of the holding surface 41a. The lost head 41 is connected to a rotary drive mechanism (not shown), and the rotary drive mechanism can be rotated under the fourth (4) of the work. The pillar portion 5 is provided in a cubic shape, and a unit moving mechanism 5 for moving the slotting unit 6 is provided on the front surface of the headrest 41. The grinding unit moving mechanism 51 has a moving mechanism by a ball type It moves in the up-and-down direction with respect to the support part 5. The shaft port 52 supports the grinding unit 6 via the support portion 53 on the front side of Amnon. The tl6 is a defensive mechanism of the present invention, and has a grinding wheel 61'. The grinding wheel 61 is freely (four) attached to the lower portion of a piston (not shown). The oscillating wheel 61 is formed by, for example, metal bonding or arranging the abrasive grains of the diamond. A mixture of fixed diamond abrasive particles. The grinding unit 6 rotates the polishing block 61 in the same direction as the rotation direction of the chuck table 41, and abuts the grinding block 61 against the surface of the guard W disposed at the grinding position, thereby working the road. Parts|surface components are ground. Happy. [WG has .1; U7 which is provided on the side of the opening of the base 2, and U7, which is disposed at the front end of the arm portion 71. ^ Fig. 2 shows that the detection (four) irradiates the laser light onto the surface of the work by the laser head 72 and receives the laser light reflected on the surface of the guard member. As shown in FIG. 3, the human laser beam has a housing η separating wall η2, an illumination system 723 for the light source and the lens, and a sensor 201236811 detector 724' connected to the control unit c by the housing 721 and The space surrounded by the separation wall 722 supplies the water supplied from the water supply port 725 provided on the side of the body 721 to the surface of the workpiece w by the drain port 726 provided under the casing 721, and the irradiation system 723 is attached to the workpiece. The surface of ~ illuminates the laser light and receives reflected light at sensor 724. Next, the control unit C detects a member exposed to the surface of the workpiece W in accordance with the change in the amount of received light of the reflected light. The control unit C that integrally controls the operation of each component of the grinding device 1 configured as described above is constituted by a microcomputer or the like having a memory for storing various materials necessary for the operation of the grinding device. Under the control of the control unit C, the grinding device 1 performs the detection processing described below. [Detection processing] As shown in Fig. 3, the laser head 72 of the detecting unit 7 detects the laser beam as the detecting light by irradiating the ground surface of the workpiece W that rotates with the rotation of the chuck table 41. Receive reflected light. Such a process is performed by appropriately changing the distance of the workpiece w (the chuck table 41) from the rotating shaft 1 in accordance with the configuration of the workpiece w to determine the path to be detected. Hereinafter, the detection processing performance of the present embodiment will be described with reference to Figs. 4 and 5 . Fig. 4 is a view showing a mode of the workpiece to be detected in the present embodiment. Fig. 5 is a flow chart showing the procedure of the detection processing. As shown in Fig. 4, the work piece w is composed of two types of members disposed on the substrate, and the first member is embedded in the second member. For example, a wafer of Cu as the first member is disposed on the substrate and covered with a molding resin as the second member. When the second member of the workpiece W is ground and the first member is exposed, 8 201236811 performs the detection process of the present embodiment. For example, when the work piece w (the chuck table 41) is rotated and the detection process is performed on the path indicated by the arrow B in FIG. 4, the detecting portion periodically receives the reflected light from the first member and the second member. The opposite 'lighting. Among them, since the reflectance of the first member is different from the reflectance of the second member, the intensity of the reflected light periodically changes. On the other hand, if the first member is not exposed due to insufficient grinding of the second member, or if the first member is not exposed (4), the intensity of the reflected light does not change even if the detection process is performed on the same path. Therefore, it can be judged that the exposure of the first member is sufficient by the intensity of the reflected light having changed.流程图 As shown in the flowchart of Fig. 5, the operator operates the operation panel 3, and when the detection processing is executed, the processing is performed, and the detection processing is performed. (4) In the processing of 81, the control unit C controls the operation of the detecting unit 7〇, and the workpiece (4) that rotates in accordance with the rotation of the chuck table 41 emits laser light and receives reflected light. (4) The amount of received light is memorized in the memory. Thereby, the processing of step ^ is completed, and the detection processing proceeds to the processing of step § 2. In the processing of step S2, the control unit c confirms the amount of memory ' in step ^ and judges the presence or absence of the change. If it has not changed (step Μ, N.), the exposure of the first member is not completed (step S3), the continuation of the workpiece % is corrected, and the process returns to step S1. In addition, there is a change in aspect 4 (step s2, 2 is that the exposing of the first member is completed (step S5), and the grinding is controlled to 6, and the::: grinding of W (step S6), ending a series of detection processing Here, the method of determining the presence or absence of the change in the amount of received light of 201236811 is specifically described in the figure of ",", "6" and "8". The figure 6 to 8 illustrate the work piece W of the fourth figure. In the path indicated by the arrow B in the figure, the intensity data of the received reflected light is measured to calculate the result of the moving average 资料 of the data. The sixth figure relates to the fact that the first member cannot be exposed due to insufficient grinding of the second member. The work piece W, Fig. 7 is a work piece W in which the second member is insufficiently ground and the first member is insufficiently exposed, and Fig. 8 is a work piece W in which the first member has been sufficiently misted after the second member is ground. In the working piece w of FIG. 4, if the moving average 强度 of the intensity data of the reflected light exceeds the predetermined definition 値 to determine that the amount of received light in the step 82 has changed, it can be determined that the exposure of the first member is sufficient. According to the reflectivity of the first member and the second member, In Fig. 6 and Fig. 7, since the moving average 値 is lower than the defined 値, continuous grinding is performed. In Fig. 8, 'the grinding average is higher than the critical value, so the grinding is stopped. The grinding process of this embodiment can also be applied. The workpiece composed of the second member is embedded in the workpiece w of the second member as shown in Fig. 9. When the working member is exposed, in the above step S1, the path of the arrow C is not detected in the figure. Therefore, when the intensity data of the light in the above steps S2 and 2 exceeds the threshold value of the light amount of the first member and the second member in advance, it is determined that the reflected light is affected and the first The component has been exposed. The detection of the first embodiment of the present invention is performed to detect the difference in the reflectance of the buried member and the second member, so that the predetermined member can be exposed, so that the high precision 201236811 can be detected. Brief Description of the Drawings Fig. 1 is a perspective view showing a configuration of a grinding device according to an embodiment of the present invention. Fig. 2 is a side view showing a configuration of a grinding device according to an embodiment of the present invention. One FIG. 4 is a schematic view showing a configuration of a workpiece W according to an embodiment of the present invention. FIG. 5 is a view showing a detection process of an embodiment of the present invention. Fig. 6 is a view for explaining a detection processor according to an embodiment of the present invention. Fig. 7 is a view for explaining a detection processor according to an embodiment of the present invention. Fig. 8 is a view for explaining the present invention. Fig. 9 is a schematic view showing a configuration of a modification of the workpiece W according to an embodiment of the present invention. [Description of main component symbols] 1. Grinding device W... Piece 6... Grinding unit C... Control unit 41.. Chuck table 70.. Detection unit