DE102005046006A1 - Wafer inspection apparatus, has color filter wheel synchronized with camera for varying illumination or image pick-up procedures for the same image pick-up region - Google Patents

Abstract

The apparatus includes an illumination device, an image-pickup device with a camera (41), and a conveying device for relatively moving the wafer (10) and image pick-up region. At least one of these devices comprises a color filter (43) which is synchronized with the camera, for varying the illumination procedure or image pick-up procedure for taking different pictures of the same image pick-up region. The color filter is preferably a filter wheel with red, green and blue filter colors. An independent claim is included for a method of inspecting a wafer.

Description

The The invention relates to an apparatus and a method for inspection a wafer with a lighting device and a recording device, wherein for inspection several different shots of the wafer or a wafer area.

An apparatus and a method of the type mentioned is DE 10 2004 004 761 A1 known. The known device has a bright field and a dark field illumination, with which the wafer can be illuminated differently for recording.

adversely It is known in the art that the inspection of the wafer is time consuming in several types of lighting.

Of the Invention is therefore based on the object, a device and to develop a method of the type described above in such a way that the inspection process is accelerated.

These The object is achieved by the device defined in claim 1 as well as solved by the method defined in claim 11. Advantageous embodiments The invention are specified in the further subclaims.

According to the invention Task in a device for inspecting a wafer, comprising a Lighting device for illuminating a receiving area of surface of the wafer in at least one particular lighting process and a recording device with a camera for receiving the illuminated Recording area in at least one specific recording procedure and a transport device for relative movement of receiving area and wafers, solved by at least one of the devices has a means of change, which is synchronized with the camera to sync Change of lighting and / or recording process for different Recordings of the same recording area.

Usually the inclusion of a wafer surface is done in partial recordings, so-called stepper Area Windows, the meandering put together one after the other from the wafer surface become. The transport device causes the respective offset from one to another recording area. For example, the wafer is covered in meandering form passed the lighting and recording device. The present invention now allows different shots of the wafer in just one transport pass. This is the proposed device faster than known devices.

Preferably it is provided that the change agent is a color filter. To this Way is achieved with just a black and white camera Color photographs of the wafer are obtained. A black and white camera is cheaper than a color camera, the invention saves investment costs.

Conveniently, it is provided that the color filter is a rotating Farbfilterrad with the filter colors red, green and blue is, for the alternating transmission of red, green and blue light. By the proposed arrangement reach the camera separated one red, one green and blue color representation of the wafer surface. By a subsequent overlay the representations by an image processing realizes a fast and easy solution for one Color photograph.

conveniently, it is provided that the color filter is arranged in front of the camera. An arrangement between lighting device is also conceivable and wafer surface.

With Advantage is provided that the illumination device means for bright field illumination and a device for dark field illumination includes and that the change means a switch between the bright field illumination and the dark field illumination is.

It Thus, a bright field and a dark field image of the wafer surface is generated, without the wafer having to be transported twice. The switch between the brightfield and darkfield lighting can alternatively or additionally be used as a means of change to the color filter. The color filter added especially the bright field illumination, in which a color image of the surface is provided. For the dark field illumination can be provided that the rotating Color filter wheel an additional fourth non-transmissive region has. Also can be provided for that the dark field illumination a color filtered area of the color filter is used, what to increase the recording Resolution can contribute.

Ideally It is intended that the camera be a monochrome area camera with a recording repetition rate of greater than or equal to 100 shots per Second, in particular greater than or equal to 1,000 Recordings per second, in particular greater than or equal to 10,000 recordings per second.

The Use of such a so-called high-speed camera has the advantage that due to the high recording repetition rate during the Period, in the lighting and recording device to a Shooting range, a variety of shots from the Recording area done. These shots, for example, after the Colors red, green and blue filtered footage and / or brightfield and darkfield footage be. A high speed camera is for cost reasons and for technological reasons generally a black and white camera. In this respect, the use of changing color filters corresponds with the black and white camera. For example, it will be convenient the filter color between each shot of the camera from the same shot area switch.

Conveniently, it is provided that the transport device the receiving area across from the wafer moves continuously.

Also the high recording repetition frequency of the high-speed camera and a short exposure time allows continuous movement between Recording area and wafer, without any motion blur occurs. Due to the continuous movement of the recording area in relation to the Wafer or vice versa, which is usually sudden movement from receiving area to receiving area avoided. Thus, shocks in the device avoided the quality of the recording and the adjustment affect the device. In addition, the continuous transport allows a faster Throughput.

To A development of the invention is provided that the change means and the device having the means of exchange a common carrier have, in particular have a common housing.

To A preferred embodiment of the invention is provided that the change means and the device having the means of change as a module are formed.

By the fixed arrangement on a common carrier or in a common casing the arrangement of changing means and device is more stable and less vulnerable for misalignment. Execution As a module has the advantage that the facility easily into the parent Plant introduced or can be removed.

Corresponding an embodiment is provided that the device in a wafer inspection system is arranged.

• – Beleuchten eines Aufnahmebereichs der Oberfläche des Wafers in mindestens einem bestimmten Belichtungsverfahren,
• – Aufnehmen des beleuchteten Aufnahmebereichs in mindestens einem bestimmten Aufnahmeverfahren,
• – mindestens einmal Wechseln des Beleuchtungs- und/oder des Aufnahmeverfahrens und
• – erneutes Beleuchten und Aufnehmen desselben Aufnahmebereichs mit dem gewechselten Verfahren,
• – Verschieben des Aufnahmebereichs relativ zum Wafer,
• – Beleuchten und Aufnehmen eines weiteren Aufnahmebereichs des Wafers.

According to the invention, furthermore, the initially stated object is achieved in a method with the following method steps:

• Illuminating a receiving area of the surface of the wafer in at least one specific exposure method,
• Recording the illuminated recording area in at least one specific recording method,
• - at least once changing the lighting and / or the recording process and
• - re-lighting and recording the same recording area with the changed procedure,
• Shifting the receiving area relative to the wafer,
• - Illuminate and record another area of the wafer.

The inventive method including its various embodiments realizes the advantages mentioned above.

in the The following is the invention with reference to a schematic representation to an embodiment explained in more detail. It shows:

1 the device according to the invention within a wafer inspection system.

A wafer 10 is from a transport facility 20 held the wafer in directions of movement 21 transported. A lighting device 30 and an image pickup device 40 focus on a recording area 12 on the wafer surface 11 , The lighting device 30 includes a dark field light source 31 , a bright field light source 33 and a switching unit 36 , The dark field light source 31 is with her beam of light 32 for oblique illumination of the reception area 12 intended. The bright field light source 33 is with her beam of light 34 over the splitter mirror 35 for vertical illumination of the receiving area 12 intended. The switching unit 36 is about a connection 37 with the dark field light source and with a connection 38 connected to the bright field light source and is provided for alternately activating the dark field light source or the bright field light source. The image capture device 40 includes a high speed black and white camera 41 and color divider wheel 43 , The high speed black and white camera 41 focused in their recording direction 42 the recording area 12 , The color divider wheel 43 protrudes in the direction of the camera and has a transparent, a red, a green and a blue filtering area. The Farbteilerrad is of a drive 44 powered and with a carrier 42 connected to the camera. Camera, carrier drive and Farbteilerrad are to a module 71 to summarized. A control and evaluation device 50 is about a connection 52 with the switching unit 36 the lighting device and with a connection 51 with the camera 41 and with a connection 53 with the drive 44 of the filter wheel 43 and about a connection 54 with the transport device 20 connected. The control and evaluation device 50 synchronizes the movement of the transport device 20 , the switching of the switching unit 36 , the filter selection by the drive of the Farbteilerrads 44 and the recording times of the black and white camera 41 together. If the transport device 20 has shifted by its continuous movement to a position in which the fixed recording area coincides with the area to be recorded on the wafer surface, a first image is taken in rapid succession by the high-speed camera, in which the recording area by the dark field light source 31 is illuminated, wherein the Farbteilerrad is rotated in its transparent position. In a second picture the camera takes 41 the recording area under illumination of the bright field light source 33 with the color divider wheel rotated to a position with red color filtering. A third image is taken with the same illumination but with the color filter turned green. A fourth image is taken in turn with the same illumination and with color filter turned to blue filtering. The result is a dark field image and three bright field images with the colors red, green and blue, the bright field images to a single color image of the control and evaluation 50 be joined together.

The Restricted invention not only to the embodiment shown. The advantages are just examples.

10

wafer

11

wafer surface

12

reception area

20

transport means

21

directions of movement

30

lighting device

31

Darkfield light source

32

beam of light the dark field light source

33

Bright field light source

34

beam of light the bright field light source

35

splitter mirror

36

switching

37

connection to the dark light source

38

connection to the bright field light source

40

Image recording device

41

High-speed black and white camera

42

shooting direction the camera

43

Farbteilerrad

44

drive of the color divider wheel

50

Tax- and evaluation

51

connection to the SW camera

52

connection switching

53

connection for driving the color filter wheel

70

Wafer inspection system

71

module

72

carrier

Claims (16)

A device for inspecting a wafer comprising a lighting device for illuminating a receiving region of the surface of the wafer in at least one specific illumination method and a recording device with a camera for receiving the illuminated receiving area in at least one specific recording method and a transport device for relative movement of receiving area and wafer, characterized in that at least one of the devices has an exchange means which is synchronized with the camera for the synchronized change of the illumination and / or the recording method for different shots of the same recording area. Device according to claim 1, characterized in that that the change agent is a color filter. Device according to one of the preceding claims, characterized characterized in that the color filter is a rotating color filter wheel with the filter colors red, green and blue is for the alternating transmission of red, green and blue blue light. Device according to one of the preceding claims, characterized characterized in that the color filter is arranged in front of the camera. Device according to one of the preceding claims, characterized in that the illumination device is a device for bright field illumination and a device for dark field illumination includes and that the change means a switch between the bright field illumination and the dark field illumination is. Device according to one of the preceding claims, characterized characterized in that the camera is a monochrome area camera with a recording repetition rate of greater than or equal to 100 shots per Second, especially greater equal 1000 shots per second, especially greater than 10000 shots per second. Device according to one of the preceding claims, characterized characterized in that the transport means the receiving area across from the wafer moves continuously. Device according to one of the preceding claims, characterized characterized in that the change agent and the change agent aufeisende device have a common carrier, in particular a common housing exhibit. Device according to one of the preceding claims, characterized characterized in that the change agent and the change agent aufeisende device are designed as a module. Device according to one of the preceding claims, characterized in that the device is in a wafer inspection system is arranged. A method for inspecting a wafer characterized through the following process steps: - Illuminate a recording area the surface the wafer in at least one particular lighting process, - Take up the illuminated receiving area in at least one particular Admission procedure, - at least once changing the lighting and / or recording process and re-lighting and recording the same recording area with the changed procedure, - Move the recording area relative to the wafer, - Illuminate and picking up another receiving area of the wafer. Method according to claim 11, characterized in that that when changing the color filtering is changed. Method according to claim 11 to 12, characterized that when changing the color filtering of the recording process changed becomes. Method according to claims 11 to 13, characterized that when switching between bright field illumination and dark field illumination is changed. Method according to claims 11 to 14, characterized that recording and resuming with an alternating frequency from greater than equal 100 shots per second, in particular greater than or equal to 1000 shots per Second, especially greater equal 10000 shots per second takes place. Process according to claims 11 to 15, characterized in that that shifting the receiving area relative to the wafer continuously during the Procedure takes place.