JP2008235460A - Wafer carrying and holding mechanisms, and sample creating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide wafer carrying and holding mechanisms capable of carrying the wafer holder by positioning it accurately and holding the wafer holder by positioning it accurately without varying the position of a wafer holder having a mounted wafer, and provide a sample creating apparatus. <P>SOLUTION: The wafer carrying mechanism 51 comprises a wafer holder 30 having a holder main body whose top surface can mount a wafer W and guide portions for positioning the wafer W on the holder main body; a carrying robot 18 having an arm in contact with the rear surface of the holder main body of the wafer holder 30 and capable of carrying the wafer W present on the wafer holder 30 by moving the arm; a positioning means 51a constituted of a plurality of recessed portions 41a, 41b formed on the rear surface of the holder main body of the wafer holder 30 and a plurality of protruding portions 43a, 43b formed on the arm of the carrying robot 18 to be engaged with the recessed portions 41a, 41b when the arm is brought into contact with the rear surface of the holder main body. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wafer transfer mechanism for transferring a wafer, a wafer holding mechanism for holding a wafer, and a sample preparation apparatus for preparing a sample from a wafer.

  A transmission electron microscope (TEM) is used to evaluate defects generated in the process of manufacturing a wafer such as a semiconductor, and observation is performed with a cross-sectional sample cut from a wafer. A sample preparation apparatus having a focused ion beam column is used for manufacturing such an extremely thin cross-sectional sample. That is, a focused ion beam is irradiated onto a predetermined portion of the wafer by a focused ion beam column and etched to form a thin piece portion having a thickness that can be observed with a transmission electron microscope to produce a cross-sectional sample. And this cross-sectional sample is taken out from a wafer, and a cross-sectional sample is observed by conveying to a transmission electron microscope.

Conventionally, in a sample preparation apparatus having such a focused ion beam column, a wafer transfer mechanism is provided, and a transfer robot that holds the wafer is held and transferred by a transfer robot that constitutes the wafer transfer mechanism. Is often adopted. In addition, a holder base for mounting a wafer holder is provided outside the sample chamber provided with the focused ion beam column, and the wafer is exchanged with the wafer holder mounted on the holder base (for example, , See Patent Document 1).
JP 2002-365182 A

  However, in a sample preparation apparatus such as Patent Document 1, when a wafer holder is transferred by a transfer robot of a wafer transfer mechanism, if the transfer robot performs an operation such as acceleration, deceleration, or turning, an inertial force that acts is applied. In some cases, the wafer holder is displaced with respect to the transfer robot. In such a case, a transfer error occurs due to the presence of the wafer holder at a position different from the schedule at the transfer destination, and the apparatus operating time is also reduced.

  In particular, when the transfer by the transfer robot is performed in a vacuum atmosphere such as the inside of a sample chamber, restrictions such as a weight limit and an operation range limit occur on the wafer holder and the transfer robot, and a complicated mechanism is provided on the wafer holder and the transfer robot. Can not be equipped. That is, as a specific mechanism of the transfer robot, for example, it is necessary to use a simple mechanism in which a wafer holder is mounted in a plate shape and transferred, and therefore the above-described problem of misalignment is likely to occur. End up.

  In addition, the wafer holder transferred from the sample chamber by the transfer robot is placed on the holder table, and the wafer is exchanged in this state. The wafer holder is transferred from the transfer robot to the holder table or from the holder table to the transfer robot. Similarly, there may be misalignment in delivery, and in such a case, there is a problem that a transport error occurs.

  The present invention has been made in view of the above-described circumstances, and a wafer transfer mechanism capable of accurately positioning and transferring without changing the position of a wafer holder on which a wafer is mounted, and A wafer holding mechanism capable of accurately positioning and holding, and a sample preparation apparatus are provided.

In order to solve the above problems, the present invention proposes the following means.
The wafer transfer mechanism of the present invention includes a holder main body capable of placing a wafer on an upper surface, a wafer holder having a guide portion for positioning the wafer on the holder main body, and an arm that contacts the lower surface of the holder main body of the wafer holder. A transfer robot for transferring the wafer on the wafer holder by moving the arm, a plurality of recesses formed on one of the lower surface of the holder main body of the wafer holder or the arm of the transfer robot; And positioning means formed of a plurality of convex portions that can be fitted into the concave portions when the arm is in contact with the lower surface of the holder main body.

  According to the wafer transfer mechanism of the present invention, the wafer holder having the wafer positioned on the holder main body by the guide unit is held by bringing the arm of the transfer robot into contact with the lower surface of the holder main body, and is transferred by the movement of the arm. . At this time, a plurality of concave portions and convex portions constituting the positioning means are fitted between the arm and the holder main body, so that the wafer holder can be accurately positioned on the arm determined by the concave and convex portions. In addition, it can be transported without being displaced due to inertial force acting during transport.

  Further, the wafer holding mechanism of the present invention is in contact with the lower surface of the holder main body of the holder main body capable of placing the wafer on the upper surface, a wafer holder having a guide portion for positioning the wafer on the holder main body, and the holder main body. A holder base for supporting the wafer holder, the lower surface of the holder body of the wafer holder, a plurality of recesses formed on one side of the holder base, and the other on the lower surface of the holder body. And positioning means constituted by a plurality of convex portions that can be fitted into the concave portions when contacted.

  According to the wafer holding mechanism of the present invention, the wafer holder in which the wafer is positioned on the holder main body by the guide portion is in a state of being supported by the holder base contacting the lower surface of the holder main body. At this time, a plurality of concave portions and convex portions constituting the positioning means are fitted between the holder base and the holder main body, so that the wafer holder is positioned on the holder base determined by the concave portions and the convex portions. Can be accurately positioned.

  The sample preparation apparatus of the present invention receives the wafer transfer mechanism and the wafer holder of the wafer transfer mechanism holding the wafer from the transfer robot and accommodates them inside, and evacuates the inside to a vacuum state. And a charged particle beam column capable of irradiating the wafer contained in the sample chamber with a charged particle beam.

  According to the sample preparation apparatus of the present invention, the wafer mounted on the wafer holder can be accurately positioned by the wafer transfer mechanism, and can be transferred without being displaced during transfer. Therefore, it is possible to process and observe the wafer by accurately irradiating the charged particle beam from the charged particle beam column to the wafer transported into the sample chamber.

  In the sample preparation apparatus, it is more preferable to include a wafer holding mechanism that is provided outside the sample chamber and has a holder base that can contact and support the lower surface of the holder body of the wafer holder. Yes.

  According to the sample preparation apparatus according to the present invention, the wafer holder transferred by the wafer transfer mechanism is placed on the holder table of the wafer holding mechanism, so that the wafer is transferred to the wafer holder on the holder table outside the sample chamber. Or it can be received.

  Further, in the sample preparation device, a plurality of recesses formed on one of the lower surface of the holder main body of the wafer holder or the holder base of the wafer holding mechanism, and the holder base formed on the other of the holder base is the holder. It is more preferable to have other positioning means composed of a plurality of convex portions that can be fitted into the concave portions when contacting the lower surface of the main body.

  According to the sample preparation device of the present invention, in a state where the wafer holder is held by the holder base of the wafer holding mechanism, a plurality of concave portions and convex portions constituting other positioning means are provided between the holder base and the holder body. Are fitted, the wafer holder can be accurately positioned at a position on the holder base determined by the concave and convex portions. For this reason, the wafer on the wafer holder can be accurately delivered or received.

According to the wafer transfer mechanism of the present invention, the positioning means is provided between the wafer holder and the transfer robot, so that the wafer holder on which the wafer is mounted can be accurately positioned and transferred without changing the position of the wafer holder. Is possible.
Further, according to the wafer holding mechanism of the present invention, the positioning means is provided between the wafer holder and the holder base, so that the wafer holder on which the wafer is mounted is accurately positioned and held without changing the position. It is possible.
Further, according to the sample preparation apparatus of the present invention, by providing the wafer transfer mechanism as described above, a wafer can be processed accurately and efficiently without causing a transfer error.

  1 to 15 show an embodiment according to the present invention. As shown in FIG. 1, the sample preparation apparatus 1 uses a wafer holder 30 shown in FIG. 2 to transfer a substantially plate-like wafer W to the sample chamber 2, and a focused ion beam (charged) in the interior 2 a of the sample chamber 2. A cross-sectional sample is produced by irradiation with a particle beam. Hereinafter, details of the sample preparation device 1 and the wafer holder 30 will be described.

  As shown in FIGS. 2 and 3, the wafer holder 30 is formed in a frame shape having an opening 31 a in the center, and a holder body 31 on which the wafer W can be placed on the upper surface 31 b, and placed on the holder body 31. And a guide portion 32 that contacts the outer periphery W1 of the wafer W and positions the wafer W on the holder body 31. The guide portion 32 is provided at four locations with a gap at equal intervals on the outer peripheral portion 31c of the holder main body 31, and a cross-section sample holding portion 33 that holds a cross-section sample prepared from the wafer W in the gap. Is provided. The cross-section sample holder 33 includes a sample cassette 34 attached to the holder body 31, a fixed base 35 attached to the sample cassette 34, and a substantially plate-like sample base 36 sandwiched between the fixed bases 35. Yes. Each of the sample cassettes 34 is detachably fitted by a pair of engaging convex portions 31e provided on the outer peripheral portion 31c of the holder main body 31. Further, the sample cassette 34 is formed with four recesses 34a, and one fixing base 35 is detachably fitted to each recess 34a.

  As shown in FIGS. 4 and 5, the fixing base 35 includes a base portion 35a and a fixing portion 35b, and a screw hole 35c communicating with the base portion 35a and the fixing portion 35b is formed. That is, the fixing table 35 can hold the sample table 36 by inserting the sample table 36 between the base portion 35a and the fixing portion 35b and tightening the fixing screw 35d into the screw hole 35c. As shown in FIG. 6, the sample stage 36 includes a substantially plate-shaped metal mesh 37 and a support portion 38 formed on the upper surface portion thereof. FIG. 6 shows a state in which the cross-section sample S is fixed. As will be described later, the cross-section sample S is bonded to the side surface 38a of the support portion 38, and a portion where the cross-section sample S is bonded is cut away. The state which formed the observation window part 38b is shown.

  Further, as shown in FIG. 7, in the wafer holder 30, substantially conical concave portions 40 a, 40 b, 41 a, and 41 b are formed on the lower surface 31 d of the holder main body 31. More specifically, the recesses 40a, 40b, 41a, and 41b are provided between the four sample holders 35, and are opposed to each other with substantially the same size as a pair formed by the recesses 40a and 40b as will be described later. Moreover, the concave portions 41a and 41b form a pair and face each other with substantially the same size.

  As shown in FIG. 1, a wafer holder 30 holding a wafer W is placed in a sample chamber 2 for producing a cross-sectional sample S from a wafer W, and the position of the wafer W can be adjusted in three axial directions and rotated. A sample stage 3 is provided to support it. The sample stage 3 only needs to be capable of adjusting the position at least in the triaxial direction. As shown in FIG. 8, the sample stage 3 is formed in a frame shape corresponding to the holder main body 31 of the wafer holder 30, and the first electrostatic chuck 3 b capable of attracting and holding the holder main body 31, and the first electrostatic chuck And a second electrostatic chuck 3c provided inside 3b. The second electrostatic chuck 3c protrudes upward so that the wafer W placed on the holder body 31 can be sucked and held in a state where the holder body 31 of the wafer holder 30 is sucked and held by the first electrostatic chuck 3b. Yes. More specifically, the second electrostatic chuck 3 c protrudes upward with respect to the first electrostatic chuck 3 b by a dimension substantially equal to the member thickness of the holder main body 31. The first electrostatic chuck 3b and the second electrostatic chuck 3c set a voltage value independently by a control unit (not shown) and apply a voltage, and generate an electrostatic force according to the voltage value. Then, each of the holder main body 31 of the wafer holder 30 and the wafer W can be sucked and held. An insertion groove 3a into which a tip arm 18c of an internal transfer robot 18 described later can be inserted is provided at the center of the second electrostatic chuck 3c.

  A focused ion beam column 4 that can irradiate a focused ion beam onto the wafer W held by the wafer holder 30 on the sample stage 3 is provided above the sample stage 3. More specifically, the focused ion beam column 4 has an ion source such as gallium ion inside, and by applying a voltage, the ions are extracted from the ion source and accelerated, and focused by an electrostatic lens. It is possible to irradiate a focused ion beam. In addition, it has a deflection electrode (not shown), can adjust the irradiation position of the focused ion beam in a predetermined range, and can irradiate a predetermined position on the wafer W by cooperating with the sample stage 3. It is possible.

In addition, a gas gun 5 capable of ejecting a deposition gas at an irradiation position of the focused ion beam is provided in the interior 2a of the sample chamber 2. The deposition gas ejected from the gas gun 5 is, for example, W (CO) ₆ and is ejected to the irradiation position along with the irradiation of the focused ion beam, thereby forming a deposition film formed of tungsten at the irradiation position. What can be filmed. The deposition gas is not limited to the above, and can be selected as appropriate depending on the material for forming the deposition film. The focused ion beam column 4 and the gas gun 5 constitute the bonding means 6, and the cross-sectional sample S can be bonded to the support portion 38 of the sample stage 36 as will be described later. Also, in the interior 2 a of the sample chamber 2, there is provided a probe 7 that is a sampling / transporting unit that samples the cross-sectional sample S produced by the focused ion beam from the wafer W and transports it to the sample holder 33 of the wafer holder 30. ing. The probe 7 is formed of glass, for example, and is an extremely fine rod-like member obtained by heating a glass rod and cutting the stretched tip portion. According to such a probe 7, since the electrostatic force is generated between the probe 7 and the cross-sectional sample S by contacting the cross-sectional sample S, the cross-sectional sample S can be adsorbed and transported.

  Further, as shown in FIG. 1, a load lock chamber 8 is provided adjacent to the sample chamber 2. The load lock chamber 8 includes two chambers, a robot chamber 9 and a holder chamber 10. The robot chamber 9 is connected to the sample chamber 2 by a sample chamber valve 11 that can be opened and closed. The robot chamber 9 and the holder chamber 10 are connected by a gate valve 12 that can be opened and closed. Further, in the holder chamber 10, as an openable / closable external valve 13 connected to the outside, a wafer valve 13 a for transporting the wafer W and a holder valve 13 b for transporting the wafer holder 30 face in different directions. Is provided. More specifically, in the holder chamber 10, the gate valve 12 and the holder valve 13b are provided facing each other, and the wafer valve 13a is provided in a direction orthogonal to the gate valve 12 and the holder valve 13b. Yes. Each of the sample chamber 2, the robot chamber 9, and the holder chamber 10 has an exhaust means (not shown), and each of the sample chamber valve 11, the gate valve 12, the wafer valve 13a, and the holder valve 13b is closed. By doing so, it is possible to evacuate the inside independently until it becomes a vacuum state.

  The holder chamber 10 is provided with a holder base 14 on which the wafer holder 30 can be disposed with a space below. As shown in FIGS. 1, 9, and 10, the holder base 14 includes a pair of main bases 15, 15 provided side by side in a direction in which the wafer W is transferred from the wafer valve 13 a to the outside, and a robot chamber 9. The four sub-bases 16 are provided with a gap in the transfer path for transferring the wafer holder 30 to the holder chamber 10 through the gate valve 12 and from the holder valve 13b to the outside. . A receiving member 15 b in which a step portion 15 a corresponding to the shape of the wafer holder 30 is formed is provided above the pair of main stands 15, 15. And the convex part 42a is formed in the upper surface of the receiving member 15b of the one main stand 15, and the convex part 42b is formed also in the upper surface of the receiving member 15b of the other main base 15 facing the convex part 42a. Has been. The convex portions 42a and 42b are formed in a substantially conical shape corresponding to the concave portions 40a and 40b of the holder main body 31 of the wafer holder 30, and the top portion 42c and the edge portion 42d are cut out. A receiving member 16 a is provided on the upper side of the sub table 16. If the wafer holder 30 is arranged on the main table 15 and the sub table 16, the stepped portion 15a of the wafer holder 30 is roughly positioned by abutting against the side surface 32a of the guide portion 32, and the lower surface 31d of the holder body 31 is received by each receiving portion. By contacting the members 15 b and 16 a, the wafer holder 30 is supported by each main table 15 and each sub table 16.

  Further, in this state, the convex portions 42a and 42b respectively corresponding to the concave portions 40a and 40b are fitted, whereby the wafer holder 30 is positioned at a position determined by the convex portions 42a and 42b. Movement and rotation are restricted on a plane formed by the receiving member 15b and the receiving member 16a of the sub table 16. That is, the concave portions 40a and 40b and the convex portions 42a and 42b constitute the positioning means 50a to position and regulate the wafer holder 30, and the wafer holder 30 and the holder base 14 include the positioning means 50a. The wafer holding mechanism 50 is configured so that the wafer W can be kept positioned and held.

  A storage recess 10a is provided on the floor of the holder chamber 10, and an elevator 17 is provided inside the storage recess 10a. The elevator 17 is fixed to the bottom surface of the housing recess 10a and can be vertically expanded and contracted by a drive unit (not shown), an arm 17b extending in three horizontal directions at the upper end of the cylinder 17a, and an arm 17b And a support pin 17c provided to protrude upward at the tip portion. As shown in FIG. 9, when the wafer holder 30 holding the wafer W is placed on the holder base 14, the elevator 17 is placed in a space below the wafer holder 30 with the cylinder 17 a contracted. Further, by extending the cylinder 17a, the support pins 17c can be brought into contact with the lower surface of the wafer W to lift the wafer W. In addition, although the elevator 17 shall be provided in the inside of the accommodation recessed part 10a, if the elevator 17 can be arrange | positioned in the space between the floor of the holder chamber 10, and the wafer holder 30 by setting the holder stand 14 high. The elevator 17 may be provided directly on the floor of the holder chamber 10 without providing the housing recess 10a.

  As shown in FIG. 1, the robot chamber 9 is provided with an internal transfer robot 18 that transfers the wafer holder 30 between the holder stage 14 of the holder chamber 10 and the sample stage 3 in the interior 2 a of the sample chamber 2. Yes. In the present embodiment, the internal transfer robot 18 includes a base arm 18a, an intermediate arm 18b, and a front arm 18c, which are three arms, and each of the internal transfer robot 18 is set to be freely rotatable by a drive unit 18d. As described above, the distal arm 18c is set to have a width that can be inserted into the insertion groove 3a of the sample stage 3, and as shown in FIG. Convex portions 43a and 43b are formed. These convex portions 43a and 43b are formed in a substantially conical shape corresponding to the concave portions 41a and 41b of the holder main body 31 of the wafer holder 30, and the top portion 43c and the edge portion 43d are cut out. If the holder main body 31 of the wafer holder 30 is supported by bringing the tip arm 18c of the internal transfer robot 18 into contact with the lower surface 31d, the convex portions 43a and 43b are fitted into the corresponding concave portions 41a and 41b, respectively. As a result, the wafer holder 30 is positioned on the tip arm 18c at a position determined by the convex portions 43a and 43b, and movement and rotation are restricted on a plane formed by the upper surface of the tip arm 18c. That is, the concave portions 41a and 41b and the convex portions 43a and 43b constitute the positioning means 51a for positioning the wafer holder 30, and the wafer holder 30 and the internal transfer robot 18 have the positioning means 51a to position the wafer W. A wafer transfer mechanism 51 that transfers the wafer in a state is configured.

  As shown in FIG. 1, outside the wafer chamber 13a side of the holder chamber 10, a wafer transfer robot 19 for transferring the wafer W and a wafer for storing a plurality of wafers W before and after the cross-sectional sample S is produced. Cassettes 20 and 21 and a wafer aligner 22 for detecting the orientation of the wafer W are provided. In this embodiment, the wafer transfer robot 19 includes a base arm 19a, intermediate arms 19b and 19c, and a front arm 19d, which are four arms, and each is set to be freely rotatable by a drive unit 19e. . A wafer W can be placed on the distal arm 19d, and the base arm 19a, intermediate arms 19b and 19c, and the distal arm 19d cooperate with each other to hold the wafer cassettes 20 and 21 and the holder chamber. The wafer W can be transferred to and from the inside of the apparatus 10.

  In addition, a holder transfer robot 23 for transferring the wafer holder 30 and a holder mounting portion 24 for mounting the transferred wafer holder 30 are provided outside the holder chamber 10 on the side of the holder valve 13b. In this embodiment, the holder transport robot 23 includes a base end arm 23a, an intermediate arm 23b, and a front end arm 23c, which are three arms, and the base end arm 22a and the intermediate arm 22b are rotated by a drive unit 23d. It is set freely. The tip arm 22c is set to slide freely on the intermediate arm 22b. The wafer holder 30 can be transferred between the inside of the holder chamber 10 and the holder mounting portion 24 by the cooperation of the base end arm 23a, the intermediate arm 23b, and the front end arm 23c.

  Next, operations of the sample preparation device 1 and the wafer holder 30 will be described. FIG. 12 shows a state in which the wafer holder 30 holding the wafer W is arranged on the sample stage 3 in the sample chamber 2. Here, on the sample stage 3, the holder main body 31 of the wafer holder 30 is attracted and held by the first electrostatic chuck 3b, and the wafer W is separated from the first electrostatic chuck 3b by a second static electricity. It is sucked and held by the electric chuck 3c. Then, the cross-sectional sample S is manufactured in a state where the sample chamber valve 11 is closed and the inside 2a of the sample chamber 2 is kept in a vacuum state by an exhaust means (not shown). As shown in FIG. 13A, first, the focused ion beam I is irradiated from the focused ion beam column 4 at a predetermined position of the wafer W held by the wafer holder 30 so that the shape of the extremely thin cross-sectional sample S is obtained. Etch and slice. Here, the wafer holder 30 and the wafer W are attracted and held by the first electrostatic chuck 3b and the second electrostatic chuck 3c by electrostatic force. For this reason, the inside 2a of the sample chamber 2 can be detached while the operator is not involved, and the generation of contaminants such as dust caused by the operator can be prevented. Further, there is no possibility of generating contaminants such as dust generated from the members, such as mechanical fastening. Further, due to the electrostatic force, the wafer W can be attracted and held uniformly over a wide range without distortion. Further, the weight of the sample stage 3 itself can be reduced, and the natural frequency of the sample stage 3 can be set high. For this reason, it is possible to prevent degradation of the resolution of the focused ion beam I caused by contaminants, deformation of the wafer W, and vibration of the sample stage 3, and processing and observation of the wafer W can be performed with higher accuracy. Further, the wafer holder 30 and the wafer W are separately held by suction by the first electrostatic chuck 3b and the second electrostatic chuck 3c. And about the 2nd electrostatic chuck 3c holding the lightweight wafer W, a required voltage can be restrained low. Therefore, the leakage current flowing through the wafer W can be reduced, and the irradiated focused ion beam I can be prevented from being affected by the leakage current. The second electrostatic chuck 3c protrudes upward so that the wafer W can be sucked and held in a state where the holder main body 31 of the wafer holder 30 is sucked and held by the first electrostatic chuck 3b. For this reason, the wafer W can be adsorbed and held so that the observation surface becomes the focal height of the focused ion beam I while being placed on the wafer holder 30, and the resolution of the focused ion beam I can be further improved. Can do.

  And after cut | disconnecting the side part S1 of the cross-section sample S, the cross-section sample S is extract | collected with the probe 7 which is an extraction and conveyance means. Then, as shown in FIG. 13 (b), one of the sample bases 36 held by the fixed base 35 of the sample holding part 33 is selected, and the collected cross-sectional sample S is brought into contact with the side face 38 a of the support part 38. Let At this time, the fixing base 35 of the sample holder 33 is provided on the holder main body 31, and thus is positioned at a height substantially equal to the observation surface of the wafer W. For this reason, the distance by which the cross-sectional sample S is collected and moved to the sample base 26 sandwiched by the fixed base 35 can be minimized, and the cross-section sample S can be prevented from dropping or breaking during movement. Then, the cross-section sample S and the support portion 38 are bonded and fixed by the bonding means 6 shown in FIG. That is, the focused ion beam column 4 irradiates the side S1 of the cross-sectional sample S with the focused ion beam, and the gas gun 5 ejects the deposition gas. As a result, the deposition film S2 is formed on the side portion S1 of the cross-sectional sample S, and the cross-sectional sample S is bonded and fixed to the support portion 38 by the deposition film S2. Further, by irradiating the portion that becomes the observation window portion 38b of the support portion 38 with the focused ion beam, the support portion 38 is etched to form the observation window portion 38b. As described above, the cross-sectional sample S fixed to the sample stage 38 can be observed with the transmission electron microscope through the observation window 38b. Further, since the cross-sectional sample S is manufactured from a predetermined position of the wafer W and is fixed to the sample holder 33, the wafer W and the manufactured cross-sectional sample S can be transported simultaneously. In the present embodiment, four sample cassettes 34 are provided in the wafer holder 30, and four fixing bases 35 can be mounted on each sample cassette 34, so that a maximum of 16 cross sections from one wafer W can be obtained. The sample S can be collected and fixed to the sample holder 33 and can be simultaneously transported. In addition, since the cross-sectional sample holder 33 that holds the wafer W and the cross-sectional sample S to be manufactured is positioned together with the wafer holder 30, the above-described cross-sectional sample S can be efficiently manufactured and collected, The interior 2a of the sample chamber 2 can be suppressed to a minimum space.

  When the preparation and collection of the cross-sectional sample S are completed, the wafer W and the cross-sectional sample S are transferred to the outside. First, the adsorption of the wafer holder 30 and the wafer W by the first electrostatic chuck 3b and the second electrostatic chuck 3c is released by a control unit (not shown). At this time, since the suction is performed by electrostatic force, the suction can be released without intervention of an operator, the working time accompanying the detachment can be shortened, and the damage of the wafer W or the like by the worker can be prevented. . In addition, since the voltage of the second electrostatic chuck 3c that attracts the wafer W can be kept low as described above, it is possible to shorten the separation time when releasing and releasing the adsorption, thereby improving the throughput. Can be planned. Next, as shown in FIG. 9, with the sample chamber valve 11 and the gate valve 12 closed, the inside of the robot chamber 9 is brought to the same atmospheric pressure as the inside 2a of the sample chamber 2 by the exhaust means (not shown). In this state, the sample chamber valve 11 is opened. By doing in this way, while maintaining the vacuum state of the inside 2a of the sample chamber 2, it is possible to prevent unnecessary dust and the like from flowing into the inside 2a of the sample chamber 2.

  Next, as shown in FIG. 14A, the internal transfer robot 18 is driven to insert the tip arm 18 c into the insertion groove 3 a of the sample stage 3. Then, as shown in FIG. 14B, the tip arm 18 c is brought into contact with the lower surface 31 d of the wafer holder 30. In this state, the convex portions 43a and 43b formed on the tip arm 18c are fitted into the concave portions 41a and 41b formed on the corresponding holder body 31, respectively. At this time, the concave portions 41a and 41b and the convex portions 43a and 43b are formed in substantially conical shapes corresponding to each other. For this reason, even if the relative positions of the tip arm 18c and the wafer holder 30 are misaligned, the wafer holder 30 is provided as long as the top portions 43c of the convex portions 43a and 43b can be inserted into the corresponding concave portions 41a and 41b. Are guided by the inclined surfaces of the convex portions 43a and 43b, and the concave portions 41a and 41b constituting the positioning means 51a and the convex portions 43a and 43b are fitted so as to be coaxial. Then, the wafer holder 30 is accurately positioned at a position corresponding to the protrusions 43a and 43b with respect to the distal arm 18c, while the distal transfer arm 18c, the intermediate arm 18b, and the proximal end are in the internal transfer robot 18. The arm 18c is rotated and conveyed to the inside of the robot chamber 9. At this time, the movement and rotation of the wafer holder 30 are restricted by the convex portions 43a and 43b fitting into the corresponding concave portions 41a and 41b in the positioning means 51a. Therefore, the wafer holder 30 can be transported while being positioned without being displaced with respect to the distal end arm 18c by the inertial force during the transport by the internal transport robot 18.

  The wafer holder 30 is a frame-like member having a holder main body 31 with an opening 31 a formed in the center. The sample holder 33 that holds the cross-sectional sample S is also composed of a sample cassette 34, a fixed base 35, and a sample base 36. It is a very simple structure. For this reason, since the size and weight of the wafer holder 30 can be minimized, the size of the internal transfer robot 18 that transfers the wafer holder 30 can be reduced. In addition, it is possible to save space on the transport route.

  Next, after closing the sample chamber valve 11, the gate valve 12 is opened. At this time, the holder chamber 10 closes the wafer valve 13 a and the holder valve 13 b which are the external valves 13, and exhausts the interior by an unillustrated exhaust means to keep the same atmospheric pressure as the robot chamber 9. For this reason, even if the gate valve 12 is opened, the inside of the robot chamber 9 can be maintained in a vacuum state. Then, the wafer holder 30 placed on the tip arm 18 c is moved to the holder chamber 10. Since the sub table 16 of the holder table 14 is arranged with a gap in the conveyance direction by the internal conveyance robot 18, the tip arm 18 c is inserted into the gap between the four sub tables 16, and FIG. 15 and FIG. As shown in FIG. 16, the wafer holder 30 can be delivered to the holder table 14. The wafer holder 30 is guided and roughly positioned by the step portion 15a. Further, as shown in FIG. 16 (b), in the pair of main stands 15, the convex portions 41 a and 41 b formed on the receiving member 15 b are fitted into the concave portions 40 a and 40 b of the corresponding holder body 31, respectively. At this time, the concave portions 40a, 40b and the convex portions 42a, 42b are formed in substantially conical shapes corresponding to each other. For this reason, even if the relative positions of the holder base 14 and the wafer holder 30 are misaligned due to an error in the position control of the tip arm 18c, the top portions 42c of the convex portions 42a and 42b correspond to the corresponding concave portions 40a. , 40b, the wafer holder 30 is guided by the inclined surfaces of the convex portions 42a, 42b, and the concave portions 40a, 40b constituting the positioning means 50a and the convex portions 42a, 42b are coaxial. As a result, they are fitted to each other and are accurately positioned at positions corresponding to the convex portions 42a and 42b. In this state, movement and rotation on the holder base 14 are restricted by the positioning means 50a.

  Next, the wafer W and the cross-sectional sample S held by the wafer holder 30 are transferred from the holder chamber 10 to the outside. At this time, after closing the gate valve 12, the external valve 13 is opened. By doing so, the robot chamber 9 can be maintained in a vacuum state. Then, as shown in FIGS. 17 and 18, first, the wafer W held by the wafer holder 30 is transferred to the outside. That is, the cylinder 17a of the elevator 17 is extended to raise the support pin 17c. Since the wafer holder 30 has an opening 31a in the center, the support pins 17c are brought into contact with the lower surface W2 of the wafer W by raising the support pins 17c. Then, by further raising the support pins 17c, the wafer W can be lifted upward and detached from the wafer holder 30. Then, the wafer transfer robot 19 is driven, and the tip arm 19d of the wafer transfer robot 19 is inserted below the wafer W lifted by the elevator 17 and brought into contact with the lower surface W2. By doing so, the wafer W is delivered to the wafer transfer robot 19. Here, the relative position relationship between the wafer W and the wafer holder 30 is maintained until the wafer W is detached from the wafer holder 30 and transferred to the wafer transfer robot 19 as described above. Further, as described above, the wafer holder 30 is transported from the inside of the sample chamber 2 and held in the holder chamber 10 while being always positioned by the positioning means 51a and 51b. For this reason, the wafer W is configured by the wafer transfer mechanism 51 including the wafer holder 30 and the internal transfer robot 18 and the wafer holder 30 and the holder base 14 until the wafer W is transferred from the sample chamber 2 to the wafer transfer robot 19. The wafer holding mechanism 50 can maintain the positioned state and can accurately manage the position. Then, the wafer W transferred to the outside by the external transfer robot 19 is stored in a wafer cassette 21 in which the wafer after the cross-sectional sample S is manufactured is stored.

  Next, as shown in FIG. 19, the cylinder 17a of the elevator 17 is contracted, and the support pin 17c is lowered. Then, the wafer valve 13a is closed and the holder valve 13b is opened. As shown in FIGS. 19 and 20, the holder transport robot 23 is driven in this state, and the tip arm 23 c is inserted into the gap of the sub table 16 inside the holder chamber 10, and the holder main body 31 of the wafer holder 30 is inserted. It is brought into contact with the lower surface 31d. Then, by moving the tip arm 23 c, the wafer holder 30 in which the cross-sectional sample S is held by the sample holding unit 33 can be transferred to the holder mounting unit 24 provided outside. After the wafer holder 30 is transported to the outside, the cross-sectional sample S is handled in units of the sample cassette 34 by detaching the sample cassette 34 from the holder body 31 of the wafer holder 30 and stored or transported to a transmission electron microscope for observation. I can do it. Note that the sample cassette 34 and the sample table 36 on which the cross-sectional samples S are fixed one by one can be attached and detached by the fixed table 35. Therefore, the fixed table 35 is detached from the sample cassette 34 in units of the fixed table 35. It can also be handled. In addition, after the observation of the produced cross-sectional sample S is completed, the sample table 36 is removed from the fixed table 35. If a new sample stage 36 to which the cross-section sample S is not bonded and fixed is sandwiched between the fixed stages 35 and mounted on the sample cassette 34, it can be mounted on the wafer holder 30 and used again. The sample cassette 34 can be transported to the next process while being held by the wafer holder 30 without being detached from the holder main body 31 of the wafer holder 30.

  As shown in FIG. 1, when the cross-sectional sample S is produced from a new wafer W, the holder holder robot 23 moves the wafer holder 30 from the holder mounting portion 24 to the holder base 14 of the holder chamber 10. Further, a new wafer W is taken out from the wafer cassette 20 by the wafer transfer robot 19, and the orientation of the wafer W is detected by the wafer aligner 22. In the holder chamber 10, the wafer W is transferred onto the support pins 17 c of the elevator 17 by being transferred by the wafer transfer robot 19 with the support pins 17 c of the elevator 17 being raised. If the elevator 17 is lowered, the wafer W can be easily positioned on the holder body 31 of the wafer holder 30 and can be held. Thereafter, the procedure is the reverse of the case where the wafer W and the cross-sectional sample S are transferred from the sample chamber 2a to the outside, and the description is omitted.

  In the above description, the wafer W is transported to the sample chamber 2 by the wafer holder 30 one by one to produce the cross-sectional sample S, and the wafer W and the cross-sectional sample S are transported to the outside by the wafer holder 30. The cross-sectional sample S can also be collected continuously. For example, it is assumed that one cross-sectional sample S is collected from one wafer W and this is performed on a plurality of wafers W. In this case, a cross-sectional sample S is prepared from the first wafer W, and the wafer W is transferred to the holder chamber 10 as shown in FIG. Next, as shown in FIG. 12, when the wafer W is transferred to the outside, a new wafer W is taken out from the wafer cassette 20 and placed on the wafer holder 30 without transferring the wafer holder 30 from the wafer valve 13b to the outside. To do. Then, a new cross-section sample S can be collected from the new wafer W by transporting it to the sample chamber 2 while holding the new wafer W and the cross-section sample S collected before that. In the present embodiment, since the sample holder 33 can hold a total of 16 cross-sectional samples S, the cross-sectional samples S can be continuously collected from 16 wafers W. As described above, since the process of transporting the wafer holder 30 to the outside for each wafer W and removing the cross-sectional sample S can be omitted, it is possible to further improve the throughput.

  As described above, by providing the wafer holding mechanism 50 having the positioning means 50a and the wafer transport mechanism 51 having the positioning means 51a, the wafer W can be accurately positioned from the sample chamber 2 to the external wafer cassettes 20 and 21. Can be carried in and out. In particular, each of the positioning means 50a and 51a is composed of a concave portion and a convex portion that are formed in a substantially conical shape corresponding to each other, so that the positioning is performed accurately only by performing approximate positioning. be able to. Further, the wafer transfer mechanism 51 is positioned during transfer, and the wafer holder 30 can be prevented from moving or rotating due to inertial force. In addition, since the sample can be accurately positioned, transferred, and held in this manner, a focused ion beam can be accurately irradiated to a predetermined position of the wafer W by the focused ion beam column 4 inside the sample chamber 2. Then, processing and observation can be performed.

  In addition, although the convex part and the recessed part which each comprise each positioning means 50a and 51a were provided so that it might respectively correspond to 2 sets, it is not restricted to this. For example, you may provide three each so that it may become three sets, and the same effect can be anticipated by having at least two or more. Moreover, the shape of a convex part and a recessed part is not restricted above, For example, about the convex part, you may form in the hemisphere which can be fitted with respect to a conical recessed part. Further, a convex portion may be provided on the wafer holder 30 side, and a concave portion may be provided in the corresponding holder base 10 and internal transfer robot 18. However, by making the wafer holder 30 side a concave portion, it is preferable that the convex portion does not become an obstacle when the wafer holder 30 is attracted and held by the electrostatic chuck 3b of the sample stage 3.

  Further, the wafer holder is not limited to the shape as described above, and may have a configuration without the cross-section sample holder 33. However, by using the wafer holder 30 that is reduced in size and weight as described above, the sample chamber 2 that accommodates the wafer holder 30 holding the wafer W and produces the cross-sectional sample S can be reduced in size. Can do. In addition, the wafer holder 30 can simultaneously transport the wafer W and the cross-sectional sample S, and the transportation route can be made into one system, so that the space associated with transportation can be reduced. In addition, since the wafer holder 30 can be reduced in size and weight, the internal transfer robot 18 that transfers the wafer holder 30 can be reduced in size, and the corresponding load lock chamber 8 can be reduced in size. As described above, since the sample chamber 2 and the load lock chamber 8 can be reduced in size, the exhaust performance when the sample chamber 2 and the load lock chamber 8 are brought into a vacuum state can be improved, and the entire apparatus is provided. As a result, downsizing can be achieved.

  Further, the load lock chamber 8 is composed of the robot chamber 9 and the holder chamber 10, so that the exhaust performance when the sample chamber 2 and each of the robot chamber 9 and the holder chamber 10 of the load lock chamber 8 are brought into a vacuum state. Can be further enhanced. Further, by lifting the wafer W from the opening 31a of the holder body 31 of the wafer holder 30 by the elevator 17, the wafer W can be easily detached from the wafer holder 30, and the wafer W and the cross-sectional sample S can be transferred simultaneously. In combination, the throughput from the transfer of the wafer W to the production of the cross-sectional sample S and the transfer of the wafer W and the cross-sectional sample S to the outside can also be improved.

  On the other hand, the transfer from the holder chamber 10 to the outside is performed in two systems by the wafer valve 13a and the holder valve 13b, so that the wafer W and the cross-sectional sample S can be efficiently transferred to the outside without complication. . Further, the wafer transfer robot 19 for transferring the wafer W to the outside and the holder transfer robot 23 for transferring the wafer holder 30 holding the cross-sectional sample S to the outside can be provided as separate mechanisms. For this reason, the wafer transfer robot 19 is a mechanism capable of performing fine operations, while the holder transfer robot 23 is efficiently used as a mechanism capable of transferring a heavy object relative to the wafer transfer robot 23. Can be transported. In addition, in the interior 2a of the sample chamber 2, the wafer holder 30 and the holder W are attracted and held by the first electrostatic chuck 3b and the second electrostatic chuck 3c of the sample stage 3, so that the operator does not intervene completely. In addition to enabling the transfer, the resolution of the focused ion beam I can be further improved, and a higher-performance cross-sectional sample can be produced.

  In the present embodiment, examples of the internal transfer robot 18, the wafer transfer robot 19, and the holder transfer robot 20 are given as the mechanism for transferring the wafer holder 30, but various known robots can be selected according to the purpose. Is something. In addition, the wafer holder 30 is provided with four sample cassettes 34 and each sample cassette 34 is provided with four fixed bases 35. However, the number of sample cassettes 34 and the number of sample cassettes 34 can be attached. The number of the fixed bases 35 can be changed as necessary. Further, the fixing base 35 may be directly fixed to the holder main body 31 without providing the sample cassette 34.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

1 is an overall view of a focused ion beam apparatus according to an embodiment of the present invention. It is a top view of the wafer holder of an embodiment of this invention. It is sectional drawing in the cutting line AA of FIG. 2 about the wafer holder of embodiment of this invention. It is the side view which looked at the sample holding part of the wafer holder of embodiment of this invention in the enlarged view. It is sectional drawing which expanded the sample holding part of the wafer holder of embodiment of this invention. It is a perspective view of the sample stand of embodiment of this invention. It is a fragmentary sectional view in the cutting line BB of FIG. 2 about the wafer holder of embodiment of this invention. It is sectional drawing of the sample stage of embodiment of this invention. It is a perspective view of a holder stand and an elevator of an embodiment of this invention. It is a perspective view which shows the detail of a main stand in the holder stand of embodiment of this invention. FIG. 5 is a cross-sectional view showing details of a tip arm in the internal transfer robot according to the embodiment of the present invention. It is explanatory drawing of the focused ion beam apparatus of embodiment of this invention. It is explanatory drawing which produces the cross-sectional sample of embodiment of this invention. In the focused ion beam apparatus of embodiment of this invention, it is explanatory drawing at the time of receiving a wafer holder with an internal conveyance robot. It is sectional drawing of the holder chamber of the focused ion beam apparatus of embodiment of this invention. In the focused ion beam apparatus of embodiment of this invention, it is explanatory drawing at the time of receiving a wafer holder by a holder stand. It is explanatory drawing of the focused ion beam apparatus of embodiment of this invention. It is sectional drawing of the holder chamber of the focused ion beam apparatus of embodiment of this invention. It is sectional drawing of the holder chamber of the focused ion beam apparatus of embodiment of this invention. It is explanatory drawing of the focused ion beam apparatus of embodiment of this invention.

Explanation of symbols

1 Focused ion beam device (charged particle beam device)
2 Sample chamber 2a Inside 3 Sample stage 3b First electrostatic chuck 3c Second electrostatic chuck 4 Focused ion beam column (charged particle beam column)
5 Gas gun 6 Adhesive means 7 Probe (collecting / conveying means)
8 Load lock chamber 9 Robot chamber 10 Holder chamber 11 Sample chamber valve 12 Gate valve 13 External valve 13a Wafer valve 13b Holder valve 14 Holder base 17 Elevator 18 Internal transfer robot 30 Wafer holder 31 Holder body 31a Opening 31b Upper surface 31c Outer peripheral portion 31d Lower surface 32 Guide portion 33 Cross-section sample holding portion 34 Sample cassette 35 Fixed stand 36 Sample stand 40a, 40b, 41a, 41b Recessed portion 42a, 42b, 43a, 43b Convex portion 50 Wafer holding mechanism 50a Positioning means 51 Wafer transfer mechanism 51a Positioning means S cross-section sample W wafer W1 outer periphery W2 lower surface

Claims (5)

A holder main body capable of mounting a wafer on the upper surface, and a wafer holder having a guide portion for positioning the wafer on the holder main body;
A transfer robot having an arm that contacts the lower surface of the holder body of the wafer holder, and transferring the wafer on the wafer holder by moving the arm;
A plurality of recesses formed on one of the lower surface of the holder main body of the wafer holder or the arm of the transfer robot, and the recess formed on the other when the arm contacts the lower surface of the holder main body. And a positioning means composed of a plurality of convex portions that can be fitted to the wafer. A holder main body capable of mounting a wafer on the upper surface, and a wafer holder having a guide portion for positioning the wafer on the holder main body;
A holder base that contacts and supports the lower surface of the holder body of the wafer holder;
A plurality of recesses formed on the lower surface of the holder body of the wafer holder or one of the holder bases, and the recess formed when the holder base contacts the lower surface of the holder body. And a positioning means comprising a plurality of convex portions that can be fitted to the wafer. A wafer transfer mechanism according to claim 1;
The wafer holder of the wafer transfer mechanism holding the wafer is received from the transfer robot and accommodated therein, and a sample chamber capable of evacuating the interior to a vacuum state;
A sample preparation apparatus comprising: a charged particle beam column capable of irradiating a charged particle beam onto the wafer accommodated in the sample chamber. In the sample preparation device according to claim 3,
An apparatus for preparing a sample, comprising: a wafer holding mechanism which is provided outside the sample chamber and has a holder base which can be in contact with and supported by the lower surface of the holder main body of the wafer holder. In the sample preparation device according to claim 4,
A plurality of recesses formed in one of the lower surface of the holder main body of the wafer holder or the holder base of the wafer holding mechanism, and when the holder base is in contact with the lower surface of the holder main body formed in the other A sample preparation apparatus comprising: another positioning means including a plurality of convex portions that can be fitted into the concave portion.

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