JP4737392B2 - Board inspection equipment - Google Patents

Description

  The present invention relates to a substrate inspection apparatus.

In a semiconductor manufacturing process, a wafer is transferred from a FOUP to an inspection unit by a transfer arm and inspected. During the transfer of the wafer, the lower surface of the wafer is vacuum-sucked at the tip of the transfer arm, and the upper surface on which the circuit pattern is formed faces upward. The wafer is vacuum-sucked in a suction hole provided at the tip of the transfer arm. Whether or not the wafer is adsorbed is determined by detecting the degree of vacuum using, for example, a vacuum gauge.
JP 2002-301678 A

  However, when the wafer is warped, there is a gap between the lower surface of the wafer and the upper surface of the tip of the transfer arm, so that the vacuum pressure on the lower surface of the wafer does not reach a predetermined value and the wafer is not attracted. As a result, the substrate inspection apparatus may stop.

  When the substrate inspection apparatus is stopped, the operator causes the substrate inspection apparatus to execute the wafer transfer operation again, or lowers the vacuum pressure threshold for determining whether the wafer is adsorbed, etc. Annoying manual work was necessary.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a substrate inspection apparatus that can reduce the burden on the operator when the substrate is conveyed due to warping of the substrate.

In order to solve the above-described problem, the invention according to claim 1 is a substrate storage unit that stores a substrate to be inspected, a transport unit that vacuum-sucks the substrate and transports the substrate from the substrate storage unit to an inspection stage, and determination means for determining presence or absence of the substrate based on the degree of vacuum with a predetermined threshold value of the portion to be adsorbed, and registering means for registering information relating to the warp of the substrate, the warpage is registered in the registration means Control means for performing control to lower the threshold and confirm the presence / absence of the substrate when the degree of separation between the portion that adsorbs the substrate and the substrate is large based on related information. .

  According to a second aspect of the present invention, in the substrate inspection apparatus according to the first aspect, the control means removes the substrate when the degree of separation between the portion that adsorbs the substrate and the substrate is large based on information related to warpage. It is characterized by lowering the conveying speed.

According to a third aspect of the present invention, in the substrate inspection apparatus according to the first or second aspect, the suction vacuum pressure at the central portion of the substrate suction portion of the transfer means and the suction vacuum at the outer peripheral portion based on an instruction from the control means. and the pressure is controlled independently, transport conditions of the substrate, characterized in that raising the vacuum pressure at spaced condition between the portion and the substrate to adsorb the substrate by the warp Ri distribution der of the vacuum pressure is larger And

  According to the present invention, it is possible to reduce the burden on an operator when transporting a substrate due to warping of the substrate.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram of a substrate inspection apparatus according to a first embodiment of the present invention, and FIG. 2 is a plan view of a wafer suction portion of a transfer arm.

  The substrate inspection apparatus includes a wafer carrier unit (substrate storage unit) 1, a transfer unit (transfer unit) 2, an inspection stage 3, and a control unit (control unit) 4.

  A plurality of wafers (substrates) (not shown) are accommodated in the wafer carrier unit 1.

  The transfer unit 2 includes a transfer arm 2 </ b> B for transferring a wafer from the wafer carrier unit 1 to the inspection stage 3. A suction hole (not shown) for vacuum-sucking the wafer is formed in the wafer suction portion of the transfer arm 2B, and this suction hole is connected to a vacuum pump (not shown) via a vacuum pipe (not shown). Has been. The transfer arm 2B is connected to a vacuum sensor 2A that detects the vacuum pressure when the wafer is adsorbed, and the presence or absence of the wafer is determined based on the detection result of the vacuum sensor 2A.

  The inspection stage 3 has a holder 3a on which the wafer transferred by the transfer arm 2B of the transfer unit 2 is placed. The inspection stage 3 has a measuring unit 3B for observing and inspecting the wafer. The inspection stage 3 is formed with a suction hole 3d for vacuum-sucking the wafer, and this suction hole 3d is connected to a vacuum pump (not shown) via a vacuum pipe (not shown). The inspection stage 3 is connected to a vacuum sensor 3A that detects the degree of vacuum when the wafer is sucked, and the presence or absence of the wafer is determined based on the detection result of the vacuum sensor 3A.

  The control unit 4 sends to the transfer unit 2 commands related to wafer transfer conditions when transferring a plurality of wafers from the wafer carrier unit 1 to the inspection stage 3. The control unit 4 is constituted by a personal computer, for example. The control unit 4 has a recipe (registration means) 5. In addition to the measurement / inspection program (inspection position and inspection content), recipe 5 stores wafer warpage information. The warpage information of the wafer includes, for example, the presence / absence of warpage, the magnitude of the warpage, and the warpage is convex or concave. The controller 4 appropriately changes the wafer transfer conditions based on the wafer warpage information.

  The change of the conveyance conditions will be specifically described.

1. The threshold value of the vacuum pressure for determining the presence or absence of a wafer is changed.

    The greater the wafer warp, the lower the vacuum pressure threshold. When the threshold value is lowered, the transfer speed is lowered in order to prevent the wafer from shifting during the transfer.

2. Addition of retry When it is determined that there is no wafer during delivery of a warped wafer, retry of delivery is performed a predetermined number of times (one or more times). At this time, conditions such as a vacuum pressure threshold and a vacuum pressure may be changed.

3. Change of vacuum pressure When the transfer arm 2B is provided with a concentric suction area (ring-shaped groove formed between adjacent ring-shaped protrusions 3b) 3c (see FIG. 2), the wafer warpage is convex. If the warp is concave, the vacuum pressure of the outer suction area 3c is increased.

  The state of wafer warpage varies depending on the size of the wafer (wafer size and thickness) and the process that the wafer has passed. The warped state of the wafer that has undergone the same process shows the same tendency.

  Therefore, when inspecting wafers that have undergone the same process (wafers of the same lot), the type of wafer and the wafer are measured by measuring the state of warpage of the wafer in advance or by visually checking the state of warpage. It is only necessary to grasp the state of warpage of the wafer for each process, and store the transfer conditions in the recipe 5 in advance for each type of wafer to be inspected.

According to the first embodiment, since the number of times the substrate inspection apparatus is stopped due to the warpage of the wafer is reduced, it is possible to eliminate the troublesomeness of the operator during wafer transfer. FIG. 3 shows the second embodiment of the present invention. 1 is a block diagram of the substrate inspection apparatus according to the first embodiment, and the same reference numerals are given to the same parts as those in the first embodiment, and the description thereof is omitted.

  This second embodiment does not change the conveyance conditions based on the warpage information stored in the recipe 5, but a retry input unit in which a retry of delivery or the like is arranged on the monitor 6 when the substrate inspection apparatus actually stops This is different from the first embodiment in that it can be performed by operating 6A-2.

  The control unit 14 is connected to a monitor 6 that displays the input area 6A. The recipe 15 of the control unit 14 stores a measurement / inspection program.

  In the input area 6A, a release button 6A-1 and a retry input unit 6A-2 are arranged adjacent to each other.

  The release button 6A-1 is a button for releasing the stop state of the substrate inspection apparatus caused by the warpage of the wafer.

  Although not shown in the retry input section 6A-2, a retry button 6A-21 for executing retry of wafer transfer when the substrate inspection apparatus is stopped due to warpage of the wafer, a threshold value of vacuum pressure or vacuum A condition input unit (setting unit) 6A-22 for setting / changing the pressure, the distribution of the vacuum pressure with respect to the periphery and center of the wafer, the transfer speed, and the like are arranged. The conveyance conditions set / changed by the condition input unit 6A-22 are fed back to the conveyance unit 2.

  In the second embodiment, when the substrate inspection apparatus is stopped due to warpage of the wafer, the retry operation is performed by operating the retry button 6A-21 on the screen of the monitor 6, or the condition input unit 6A-22 is operated. Then, transfer conditions such as a vacuum pressure threshold, a vacuum pressure, a distribution of vacuum pressure on the wafer, and a transfer speed are changed.

  When the vacuum pressure threshold is changed, the condition input unit 6A-22 sets a transfer speed that is higher than the allowable wafer transfer speed with respect to the changed threshold value in order to prevent the wafer from falling. I can't do it.

  According to the second embodiment, the retry button 6A-21 and the condition input unit 6A-22 are arranged adjacent to each other on the screen of the monitor 6, and the threshold value and the condition input unit 6A-22 are operated by operating the condition input unit 6A-22. Since the vacuum pressure can be changed, the troublesomeness of the operator at the time of wafer transfer can be eliminated. Further, even if the warping conditions of the wafers stored in the wafer carrier unit 1 are different, the optimum transfer conditions can be set for each wafer.

FIG. 1 is a block diagram of a substrate inspection apparatus according to a first embodiment of the present invention. FIG. 2 is a plan view of the wafer suction portion of the transfer arm. FIG. 3 is a block diagram of a substrate inspection apparatus according to the second embodiment of the present invention.

Explanation of symbols

  1: Wafer carrier part (substrate storage part) 2: Transport part (transport means) 3: Inspection stage 4, 14: Control part (control means) 5: Recipe (registration means) 6: Monitor 6A- 2: Retry input unit, 6A-21: Retry button, 6A-22: Condition input unit (setting means).

Claims (3)

A substrate storage section for storing a substrate to be inspected;
Transport means for vacuum-sucking the substrate and transporting the substrate from the substrate storage unit to an inspection stage;
Determining means for determining the presence or absence of the substrate based on a degree of vacuum of a portion that adsorbs the substrate and a predetermined threshold;
Registration means for registering information related to warpage of the substrate;
Control means for performing control to lower the threshold value and confirm the presence or absence of the substrate when the degree of separation between the portion adsorbing the substrate and the substrate is large based on information related to warpage registered in the registration means; A board inspection apparatus comprising:   2. The substrate inspection apparatus according to claim 1, wherein the control means reduces the speed at which the substrate is conveyed when the degree of separation between the portion that adsorbs the substrate and the substrate is large based on information related to warpage. . Based on the instruction from the control means, the suction vacuum pressure at the center of the substrate suction portion of the transport means and the suction vacuum pressure at the outer periphery thereof are independently controlled,
The transport condition of the substrate is the distribution of the vacuum pressure, and the vacuum pressure is increased at a portion where the substrate is adsorbed by the warp and the substrate is largely separated. Board inspection equipment.

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