JPS62229016A - Pattern inspecting device - Google Patents

Abstract

PURPOSE:To achieve a higher measuring efficiency and a lower equipment cost, by performing an inspection and a measurement at various parts based on image information obtained with one line sensor. CONSTITUTION:A pattern forming substrate 16 as an object 4 to be measured is placed on a X-table 3, a Y-table 4 and a turn table 5 separately driven by a table control section 15 controlled with a computer 16 for control. Light emitted from an illumination light source 1 is converted by a lens 2 to light the pattern forming substrate 6. Pattern information on the pattern forming substrate 6 is focused on a line sensor 8 with a lens 7 and converted to an electrical signal according to the density thereof. The signal is read out by a line sensor control section 9 and inputted into a shape defect inspector section 10, a pattern edge detector section 11 and a image quality measuring section 12 separately.

Description

[Detailed Description of the Invention] (Objective of the Invention) '□ (Industrial Application Field) The present invention relates to a pattern inspection device, and particularly relates to a pattern inspection device for a semiconductor device, a mask for a semiconductor device, and a mask for a printed U-board. It is used for inspections such as

(Conventional □ technology) In the process of creating photomasks for semiconductor devices and arc work for printed U-boards, the pattern data is not necessarily created according to the designed pattern data, and various errors occur, so the final pattern may not be accurate. Accuracy measurement is required. − For this reason, items similar to conventional methods are tested.

m. Pattern shape and defect inspection stage: 41 Checks for coincidence with the pattern shape and existence of unnecessary patterns and missing member patterns.

(11) Pattern line width measurement This is to check whether the pattern line width is within a predetermined tolerance δ error with respect to the set d1 dimension.

(iii) Pattern coordinate measurement Errors in pattern coordinates relative to a reference point and distances between patterns are investigated.

(iv) Relative viscosity measurement This is a method for measuring the relative distance of the J5 pattern coordinates between the objects to be inspected on which a plurality of other patterns are formed.

(V) Image Quality Measurement This is to check whether the pattern iIl edges are clear, that is, the linearity of the pattern edges is good.

By the way, measuring devices have been developed for each of the above-mentioned measurement items. For example, the pattern shape and defect devices are described in Japanese Patent Laid-Open No. 11i156-54038, Japanese Patent Laid-Open No. 59-63725, etc. As a Bakun line width measuring device, the one described in Japanese Patent Application Laid-Open No. 58-38806 is known.

However, each of these conventional devices had only a single function.

(Problems to be Solved by the Invention) For this reason, in the past, it was necessary to change the apparatus for each inspection item, which required a large amount of time for inspection and measurement, and was very inefficient. Also, if there are many measurement items, it is necessary to prepare many devices.
There is a problem of avoiding an increase in equipment costs because the equipment has to be removed.

(Structure of the Invention) (Means for Solving the Problems) A pattern inspection apparatus according to the present invention includes a scanning section on which a measurement object is mounted, which moves the pattern to be inspected, and gives a desired position and rotation; A line sensor that obtains an electric signal corresponding to the line sensor from the pattern image, a shape and defect inspection section that inspects the pattern shape and defects based on the electric signal obtained from the line sensor, and an electric sensor. It includes a pattern edge detection section that detects pattern edges based on signals, and a measurement section that tests various pattern characteristics based on the pattern edge information obtained by the pattern edge detection section.

(Sakukawa) In the pattern inspection device of the present invention, one line sensor has J
:Using the obtained image information of the pattern to be measured, one device can perform fff r shape, defect inspection, pattern edge detection,
From the detected pattern edges, various pattern characteristics such as pattern width, pattern coordinates, pattern error, etc. are inspected.

Therefore, measurement efficiency is improved and equipment costs are reduced.

(Example) Hereinafter, an example of the pattern inspection apparatus according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a configuration block diagram of a pattern inspection section r1 showing an embodiment of the present invention.

A pattern-formed substrate 6 to be measured is placed on an X table 3, a Y table 4, and a rotary table 5, each of which is driven by a table control unit 15 controlled by a control IT/W machine 16. The pattern-formed substrate 6 is illuminated with light emitted from the illumination light source 1, which is focused by the lens 2. The pattern information on the pattern forming substrate is focused by the lens 7 on the licensor 8 and converted into an electric signal according to the brightness and darkness.The J: lever signal is read out to the line sensor control section 9, and the shape/defect inspection section 10,
The signals are input to a pattern edge detection section 11 and an image quality measurement section 12, respectively. The position of the lens 7 is adjusted by an automatic focus control section 13 under the control of a control computer 16 to obtain an appropriate focal position.

Parts 10, 11, and 12 for inspection and measurement are for control purposes. i
[Under the control of f116, perform (1) pattern shape and defect inspection, (11) pattern line width measurement, (iii) pattern coordinate measurement, (iv) relative viscosity measurement, and (V) image quality measurement section. When the data is sent to the magnetic disk device 18 and saved, it is displayed on the conversation terminal 19,
It is printed by the printer 20.

FIG. 2 is a block diagram that does not show the configuration of the control unit 9 that controls the line sensor, in which the line sensor control signal generation circuit 91 outputs the line sensor drive signal Sd to the line sensor 8, and synchronizes the scanning start. Signal S OJ: and output timing signal S also 5ync
c I k is output, but the latter two are this line sensor! The signal is also input to a sensitivity unevenness correction circuit 93J3 and an A/D converter 94 provided in the IJ 111 section 9, and these are synchronized.

The signal S outputted from the line sensor 18 according to the brightness and darkness of the pattern is amplified by the amplifier 92, and after correction of the sensitivity unevenness is performed by the sensitivity unevenness correction circuit, the A/D:I inverter 94
A digital output signal Sb is output.

FIGS. 3 and 4 are diagrams for explaining the functions of the above-mentioned S, S a 5 sync S and the sensitivity unevenness correction circuit 93. FIG. 3 shows how the transparent pattern portion 32J3 and the opaque pattern portion 33 are read by the line sensor 8 within the enlarged field of view 31.

The line sensor has n pictures Mp1 to po.

Figure 4 shows how the image was taken in the condition shown in Figure 3.
Then, outputs mJfv, V2, V3, . . . Vo are obtained for each pixel lk according to the timing signal S from the sync point at the time S given at the start of reading.

However, in a line sensor, the output is not constant due to nonuniform illumination, etc., and the output voltage is high in the center, as shown in FIGS. 4(a) and 4(b). Therefore, the sensitivity unevenness correction circuit 93 stores such a known tendency as a correction coefficient for each pixel, and adjusts the output voltage accordingly.
The output voltages are equally distributed as shown in S' in (b) and (b).

Next, the shape/defect inspection section 10 compares the design data read from the C11u tape device 17 via the control device 16 with the pattern data sent from the line senna control section 9, and identifies points of difference. It is something to detect. Defective data that does not represent such a difference is stored in the magnetic disk device 18 and displayed on the conversation terminal 19.

Next, FIG. 5 shows the configuration of the pattern edge detection section 11.

The line sensor digitized output S output from the line sensor control section 9 is input to the gate circuit 41.

On the other hand 1. ? Start synchronization signal to i number circuit 43 @S
and output timing signal ync Sclk are input, this counting circuit 43 counts the pixel number, and its output digital comparator A4
2 is entered. Pixel selection data D for selecting a specific pixel from the control R1 [i16] is also input to the digital 5 inverter 42, and when the both thread signals and the pixel selection data match, a match signal is output to the gate circuit 41. be done. In addition, the J: recut times m 41 G; t digitized output S is sent to the digital comparator B44 as Sb'.

What about digital comparator B44? Since the edge level definition data D for defining the edge level for the sensor 1 output data has been input, this and S'
are compared, and when D >Sb', s. dg=.

S when D ≦S ′. The edge detection signal S is sent to the control aircraft 16 under the condition of d,=1. Note that when no matching signal is output from the digital comparator Δ42, the output of the gate circuit/circuit 41 becomes O'', so it is possible to selectively extract the output data of any pixel. □Figure 6 6A and 6B are explanatory diagrams of the pattern edge detection section, where FIG. 6(a) shows how a vertical edge is detected and the X coordinate of the edge is determined, and FIG. 6(b) shows how a horizontal edge is detected and the edge is determined. This figure shows how to find the Y coordinate of the pixel p in the line sensor 51. In such a case, the X table or Y is controlled by the control unit 15 which received the command number of control ii[1fi16.

Figure M□7' is a waveform diagram showing how the pixel p-pattern 21 edge 54 is detected in Figure 6(a).
The signal S' output from the gate circuit 41 in the figure is initially at the high level 1) because it is detecting a transparent pattern, and the signal S' output from the gate circuit 41 in the figure is at the high level 1) due to the detection of the transparent pattern.
Level D is defined as the edge level. and digital comparator 4. /I, so its output is edge detection (5 sira S is 1'')
I'm in g. When the pixel pk crosses the edge of the pattern 52, an opaque part of the pattern is detected and the signal S,' falls and the signal J
Vjilevel D. When the edge detection signal S becomes lower than
changes to 0''. When this change dg occurs, the control til 19116 reads the X coordinate from the laser length measurement control unit 14, and this becomes the Y coordinate of the inter-pattern distance 54.

By using the edge coordinates of each pattern obtained in this way, the line width of the pattern, the coordinates of the pattern, the distance between patterns, and the relative vJ degree with respect to other patterns can be obtained, and these measurements are used for control purposes. A total of 0 Tsuki 16 will be used.

Figure 8 looks like this? This is an example of one measurement, where a pattern L has edge coordinates L in the X direction and Ly x 1 × 2ゝL jI3 and l- in the y direction, and M in the X direction and M in the Myh direction as edge coordinates. 1×1
Pattern M is shown to the right of ×21 and My2.

When the line width of the pattern L is found using these coordinates, there is r, and the line width of the pattern M is similarly obtained.

Also, the center coordinates of the pattern (fJ, jI,), (mx,
my) becomes, so the distance I between the center coordinates of pattern 1- and pattern M, and I, can be calculated as x.

FIG. 9 is a diagram showing a pattern for determining the relative accuracy between two pattern-formed substrates A d3 J: and 8 on which the same shape pattern is formed. If the center distances between the two corresponding patterns are IxIJ3 and ■,1 on board A, and 'x2 and ■,2 on board B, then the relative accuracy ΔX J3 and Δy can be found as ''.

Next, the image quality measuring section 12 shown in FIG. 10, which measures the linear error of the pattern edge portion, will be explained.

FIG. 10 is a block diagram showing the configuration of the homogeneity measuring section 12, and shows the digitized sensor output Sb, which is generated from the A/D converter 94 in FIG. )
The data controller 51, to which the signal output timing signal YNC8-CLK and the signal output timing signal YNC8-CLK are input, writes data for one scan of the line sensor to the buffer memory 52 from these signals, and at the same time outputs the data write timing signal -', Since this timing signal T is manually input to the control calculation n16, the control calculation unit 16 uses this timing signal to retrieve data D for one scan of the line sensor from the buffer memory 92. , can be read.

11 and 12 do not show the pattern for calculating the non-direct tit vt difference of edges, but as shown in FIG. It is assumed that p1 to pN are detected by the line sensor 101 on the right. The line sensor 101 is Y, Y
, Y, . . . , Zumbling of the image data is performed by moving by ΔY in the Y direction 1 2 :3 up to Y8. The output of this line sensor is the pattern transparent part 102.
In the opaque part 104, the maximum value is haV, but in the opaque part 104, the minimum value (+(IV), becomes C1nJ3), and in the Ni part, there is a sudden change of 1° as described above.

Here, vm, x/2 is selected as the level that defines the edge, and the point that reaches this level is defined as the edge.
6゜Figure 12 shows the pattern of detecting two points Y and an edge that falls on Y, and the edge E at Yl,l:Jj is located at a distance of 1lfiDJ from the Y1 position.
The edge E at Y is located at a distance of 1!1llDK from the Y1 position. Therefore, among the distances between each point, the maximum distance D and the minimum distance Dl.

If max is found, the non-linear error E of the pattern edge 103 is E=D −D,...
(7) It will be expressed as IRaX mln.

Note that the non-linear error can also be expressed by the following equation.

or □, and (8) is the difference between this average value and the maximum value, (
91G, L shows the difference between the average value and the minimum value.

In this manner, the pattern inspection apparatus of the present invention performs various measurements using six pieces of image information obtained by one line sensor.

Each of the inspection and measurement units shown in the examples is not limited, and may be any unit that can perform similar functions.

〔Effect of the invention〕

As described above, according to the present invention, one line sensor allows 1! Since inspections and measurements are performed in each part based on the image information collected, a single device can perform various inspections and measurements, improving measurement efficiency. In addition, the device can be configured at a much lower cost than preparing various measurement radicals separately, and equipment costs can be reduced.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of the pattern inspection device according to the present invention, Fig. 2 is a block diagram showing the configuration of the line hin) J-control section, and Fig. 3 shows the pattern of pattern detection. A block diagram, Fig. 4 is an explanatory diagram showing the state of sensitivity unevenness correction, Fig. 5 is a block diagram showing the configuration of the pattern edge detection section, and Fig. 6 is an explanatory diagram showing the pattern of edge detection. 8 is a waveform diagram showing the signals at edge detection U and 'l, FIG. 8 is a dimensional explanatory diagram showing the position between two patterns, etc., FIG. FIG. 10 is a block diagram showing the configuration of the image quality measuring section, FIG. 11 is an explanatory diagram showing how nonlinearity of pattern edges is measured, and FIG. 12 is a waveform diagram showing nonlinearity detection. 8... Line sensor, 9... Line sensor control unit,
10...Shape/defect inspection section, 11...Pattern edge. Detection unit, 12... Quality measurement unit, 13... Automatic focus control unit, 14... See 1 ar 8 l 1 length il 1 part, 15
..., table □ system 60 copies, 16... control calculator. Applicant's agent: Satoshi Sato. →t (α) Part (b) Figure 4 Figure 7 Figure 11 Hand M: ? Ichi Tadashi - Katana 1 Meiwa 61 I Special Features' [Applicant (307)
Toshiba Corporation 4 Representative Manager Ill l1ll ;'! The section ``Detailed Description of the Invention'' of ``-8i'llj, I'')p, ej゛-ri details shop, page 17, bottom line ``in the Edge Department'' to page 18 [f, line 1'' of the same page are shown. ” Add the description in the attached sheet to the darkness. tri MiJ It changes rapidly as mentioned above. Here, select the level CVIIlax/2 that defines the edge, and then set the point at which this level is reached as the edge. Figure 12 shows the pattern of edge detection at two points Y and Y, and the edge opening at Y and J).
is at a distance f4II D from Y1 position δ, and YK
The edge "K is at the position II?1 from Y1 position δ to the distance 11i1fD. Therefore, if [, the maximum distance D among the distances of each point, the minimum one 1)" is found, the pattern m
ax man edge 10
3 non-linear re: ;! ; E is E=D −O,・
...(7) It will be expressed as +11aX 11111. Please note that I am not direct! 2) can be expressed as b by the following formula. 2 or 2 ■ - Kishi 2 N city i engineering t! 1 April 24, 1985 1 ? 5 u'l Agency I〈Government Uga Michibu-dono 1 °Ii l'l Indication 11 Relationship with '1 Patent h'F Applicant (307') Stock Company 6 Toshiba 4 Representative Director 6 Urame J=J Koheri --- Raru Ippatsu Ichime Ichi Ichi 11 7 rdi It's Su・1 Elephant Ill 111 Book

Claims (1)

[Claims] 1. A scanning section on which a measurement object having a pattern to be inspected is placed and given arbitrary position and rotation; a line sensor that obtains an electric signal corresponding to the pattern image; and this line sensor. a shape and defect inspection unit that inspects the shape and defects of the pattern based on the electrical signal obtained from the electrical signal; a pattern edge detection unit that detects pattern edges based on the electrical signal; and the pattern edge detection unit A pattern inspection device that includes a measurement section that inspects various pattern characteristics based on pattern edge information obtained in the above. 2. A claim in which the measurement unit measures at least one of pattern width, pattern coordinates, distance between patterns, relative accuracy of the same pattern between different objects to be measured, and linearity of pattern edges. The pattern inspection device according to item 1.