DE19846938A1 - Method for separating required chips from semiconductor wafer - Google Patents

Abstract

The method involves using a laser beam, whose optical axis for scanning an x-y plane is controlled by a digital scanning control device. Severing raster distances are input along an x and a y axis, corresponding to the chip dimensions, of a scanning control device. The co-ordinates of a non-scored line region with respect to the control device are determined for the above input step. Then the scored lines are formed by laser irradiation, except in the non-scored line region. The control device carries out scanning of the laser beam optical axis over the wafer in the determined raster spacing along an x and y directions. The optical axis then scans in the other direction in the raster spacing for chip severing.

Description

The present invention is in the field of Semiconductor manufacturing and refers to a process the separation of a large number of functional elements like semiconductor circuits built on a semiconductor wafer fer are formed by cutting the wafer into individual Chips in the context of a semiconductor production.

In a method of manufacturing semiconductors will require a large number of semiconductor circuits formed on a semiconductor wafer, which examined and then cut into chips, creating components will create. As a method of cutting chips there is the scribing process of a semiconductor wafer, at which scratched lines on the semiconductor wafer surface surface using a diamond edge or a sharp point drawn and the chips by splitting the wafer along the incised lines are separated.

A dice method is also known, in which a slit on a semiconductor wafer surface by means of egg nes thin diamond wheel is formed, which with a high speed rotates while the wheel of the surface surface of the semiconductor wafer is supplied, and the wheel ent is advanced along its surface, causing the wafer in Chips is cut.

Furthermore, such a technique has recently been developed has been wound, in which a laser beam onto a wafer directed and moved along a scribe line where through the semiconductor layer to form a notch is melted, which separates the wafer into chips.  

With the mechanical marking method (or dice method ren) according to the state of the art after setting a Semiconductor wafers on an object table of a scriber device and entering a chip cutter pitch in the control device of the scriber a large one number of parallel incised lines or grooves in the Semiconductor wafers with grid spacing in X-Rich tion formed while a large number of parallel turned on lines or slits similarly formed in the Y direction which is aligned perpendicular to the X direction is after which the chips are separated and only the ge desired chips can be selected from the separated chips.

With this method the angle between the movement direction of a diamond edge or a diamond wheel and one on a semiconductor wafer, which is based on an ob ject table is set, drawn vertical or horizonta len scribe line measured while the stage movement and the rotation of it and the movement are controlled whereby a positioning of the rim or the wheel is performed leads and the angle thereof is corrected accordingly becomes.

A semiconductor chip separator which has a La serstrahl used is in Japanese patent Publication JP-4-180649. With this before direction is a chip from a semiconductor wafer as an analy seprobe selected and by cutting with a laser beam separated. In this process, a CCD-Ka mera an image of the top surface of the semiconductor wafer and displays the image on a monitor, the Ko ordinates which the profile of a desired one to be scanned Define ten chips, a graphic representation of the wafers displayed on the monitor are entered, whereby a removal of only the chip by heating the be  tuned blocks using a laser beam during loading movement of the laser optics is carried out.

It is known that even if one is on one Semiconductor wafer drawn scribing line directly with a La is irradiated because of the efficiency of marking a low absorption efficiency of laser energy regarding the semiconductor laser is very low. Thus, egg ne technology known which makes it easier to semiconductor chips to separate using a laser beam. The Japanese Pa For example, JP-A8-264491 discloses a method in which a semiconductor layer of Separation lines on the semiconductor wafer are removed to a Metal conductor layer on the back surface of the Expose substrate, and the laser beam on the metal Layer is directed to melt and in To cut chips. An international reveals similarly PCT patent application (issued by Mitsubishi Electric Corp. submitted international publication AP162763) Process that makes it easier to use a semiconductor wafer cut by means of a laser beam, with a half conductor layer is removed from a semiconductor wafer the functional elements along scribing lines are, whereby grooves are formed, which by a Me tallschicht are set, and the laser beam on the Metal conductor layer is directed to melt them and cut into chips.

However, these mechanical scribing methods are Separation of chips by cutting a wafer continuously Lich from one edge to an opposite edge suitable, but they are not only for separation Suitable chips, which at a desired position is located inside the wafer since the incised Lines or creases by moving a marking sheet  or knife or a diamond wheel along straight lines be formed.

While a suitable chip by scribing after the Formation of a large number of semiconductor circuits required gene was separated on a semiconductor wafer and then the semiconductor circuits were examined and the appropriate Nete chip, which the relevant semiconductor circuits has been identified, the required chip is which carries the appropriate semiconductor circuits the separation of all chips regardless of whether they are needed be or not.

It is also in a case where two and more types of semiconductor circuits with different Chip size are formed on a semiconductor wafer and a Cutting only one kind from the semiconductor wafer not possible to cut off other types of chips and in this case the chips have to be of a different kind can be cut off from another semiconductor wafer. The Cut off two or more types of semiconductor scarf semiconductor wafer requires the semi-lead arrange circuits in a special layout, what cannot always be done.

The chip scanning method using the laser beam, which is published in Japanese Patent Publ JP-A4-180649 and this ver driving are applicable when only certain chips from cut off the wafer. However, this requires ver drive too much with regard to the definition of the coordinates Time, which leads to a reduction in efficiency when only a large number of chips required Number of semiconductor wafers to be separated and is not practically suitable for mass production.  

Since in the case of chip separation using a La the efficiency of the laser beam when heated Nes wafer substrate material is low and in particular ne metal layer reflects the laser beam and a ge efficiency in absorbing laser energy shows the development of a new technology of the An needed at high speed. In this regard In the following, a technology is proposed in which Scribe grooves in advance on a semiconductor wafer cutting chips so that it can be written the marking grooves are made easy by the laser beam to cut or melt, reducing the speed of chip cutting is increased (Japanese patent Application No. 8-173960).

The object of the present invention is under Be considering the difficulties described above Process for cutting a semiconductor wafer into chips to sit back, using the procedure to set the Koor chips for efficient cutting of one large number of chips from the semiconductor wafer during the Scribing with a laser beam is suitable.

The present invention provides a method of cut a small number of certain chips from one Semiconductor wafer ready.

The present invention further adjusts Chip separation process ready, which for cutting off two or more types of semiconductor circuit chips with un different shape or structure, on a half conductor wafers are formed during the classification of the Chips are suitable in the way.

The present invention provides a method of separation of certain chips from a semiconductor wafer  Irradiate the scribe lines which are on the semiconductor wafer are drawn, ready with a laser beam, which for Ab scanning over an X-Y coordinate plane by a scan Control device is controlled, which is a numerical Control the positioning of the laser beam for scanning of the semiconductor wafer.

The method of the invention comprises the steps:

• a) Enter cutting grid dimensions along the X- Axis and the Y axis according to the dimensions of the Chips on the semiconductor wafer, creating imaginary scribes not be formed on the coordinate plane;
• b) Entering X-Y coordinate values of a non-an tear line area in relation to the imaginary marking lines not the scan controller; and
• c) scanning with a laser beam of the semiconductor wafer according to the grid dimension, which for the directions in the X and Y axes is determined under the control of the Laser beam scanning control device during irradiation the scribe lines other than the non-scribe line area where are formed by slots or grooves in the wafer and the wafer is cut into chips.

According to the chip separation method of the present Invention, the laser beam scans along the Directions of the X and Y axes on the X-Y coordinate plane through, and the scribe area becomes the cut with irradiated with the laser beam. Therefore, the grid spacing for the directions of the X-axis and the Y-axis under the Prerequisite or acceptance of the marking lines entered, while the grid spacing corresponds to the length and the Width of the chip can be determined. After that, he won't be with the area to be irradiated with the laser beam, namely the koor  of the non-scribe line area is determined such that the irradiation with the laser beam in the particular loading is richly stopped while the scribe lines in others Areas are irradiated with the laser beam, whereby Chips are cut off. In this case, an area the scribe lines in which neighboring chips are not from separated from each other without irradiation with the laser beam are selected as the non-marking area. With this Procedures reduce the labor of determining the coordinates of the area when cutting a large one Number of chips, which makes it possible to quickly get one large number of desired chips from a semiconductor wafer cut to size.

The laser beam scan controller includes one Mechanism that determines the relative position of the optical Axis of the laser beam with respect to the top surface of the Controls semiconductor wafers, which on the stage pla is adorned. A mechanism can be used for this purpose with a laser beam emission end set and the stage on which the wafer is placed, is controlled for movement, and it can also be a me Mechanism used, which is the movement of the laser controls. Regarding the control device can if a mechanism of deflecting the laser beam to Change the angle of incidence as a replacement device be det.

The method of the present invention includes Steps of entering the grid spacing as a block grid distance, which comprises two or more chips, for formation a block area on the coordinate level and the determin the pitch of each chip in each block area.

The method of the present invention includes the further the step of determining a wide area  tear area, which contains a large number of chips the determination of the non-marking area. In this The scribe lines, which are outside the wide scribing area, defined as area, which are not irradiated to the scanning laser beam should.

If the function of determining the wide range tear area is used, the area outside the large marking area not irradiated with the laser beam, and therefore the non-scribe area can only can be determined within the large marking range.

If there is a large marking area within the loading area realm of the wafer on which chips are formed the area of the wafer near the edge of which the chips are not formed from irradiating area are excluded, making it the efficiency of the coordinates is determined improvement operation.

The coordinate determination operation for the area can preferably when cutting a chip or we certain chips from the wafer are used where is simplified by the coordinate determination operation.

The method of dicing chips from a semiconductor wafer in accordance with the present invention further includes the steps:

• d) Entering the coordinates of two positioning mar cations, which are provided on the semiconductor wafer, the scan controller in advance;
• e) Detecting the two positioning marks, wel che are provided on the semiconductor wafer on the  Object stage is attached, by means of a position report solution device, whereby the X and Y coordinates of the Mar markings are determined;
• f) comparing the determined coordinates of the markie and the detected coordinates of the markings, where by shifting and rotating the scanning gate Laser beam coordinates with respect to the wafer coordinates be voted; and
• g) scanning by the laser beam along the X axis and the y-axis simultaneously in one direction, which is around is inclined an angle of rotation in step c), the Slits or grooves created by laser beam scanning be det.

Since this enables the coordinates in the Method of laser beam scanning with the angle of rotation θ too correct, the optical axis of the laser beam gives way not off the scribe line on the wafer and it will be there here an adjustment of the angle of rotation θ by turning the Wa he or the object table as in the prior art needed.

The present invention is described in the following Be scribing explained with reference to the drawing.

Fig. 1A shows the coordinates on the condition that a non-scribing line area for imaginary scribing lines is determined by inputting grid spacings on a coordinate level in the chip separation method according to an embodiment of the present invention. FIG. 1B illustrates the top surface of a divided wafer after irradiation of scribe lines that were not determined in the non-scribe line area on the wafer during the chip separation process similar to FIG. 1A.

Fig. 2A, the upper surface of a wafer is using a method of irradiating is of the wafer with the La displayed serstrahl, wherein the optical axis of the laser beam moves along the direction of the X axis, where by in the method of separating chips According to an embodiment of the present invention tear lines are formed. FIG. 2B shows the upper surface of the wafer, a method of scanning in the direction of the Y axis being displayed after the irradiation with the laser beam shown in FIG. 2A.

Fig. 3 shows the coordinates of the correction of the coordinates of the wafer from the stage viewed in the method of chip removal according to an embodiment of the present invention.

FIG. 4 shows a flow diagram illustrating the method of chip dicing according to an embodiment of the present invention.

FIG. 5 illustrates the top surface of a wafer, showing a wide scribe area that is used in determining the non-scribe line area according to an embodiment of the present invention.

Fig. 6A shows a cross-sectional view of a wafer in the process of separating chips to an embodiment of the present invention accordingly is ver turns, and Fig. 6B shows a plan view of the illustrated in Fig. 6A wafer.

To in the process of chip removal the before lying invention a large number of functional ele elements such as integrated circuits or other electronics circuits formed on a wafer in individual chips, each carrying an element scribe lines between chips with a laser beam irradiated, causing an automatic line scoring is performed on chips. In this procedure, a Scanning position of the optical axis of a laser beam a scan controller using a numeri controlled control, whereby desired chips from the Semiconductor wafers separated by means of a laser beam the one whose scanning is controlled in the X and Y directions.

As a method of mechanical or mechanical application tear processing, which ver in the present invention there is a direct Ab procedure scanning a laser beam across the top surface of the Wafers, which is fixed and a process of moving gene of the wafer and the stage together the specified laser beam. The former method of direct scanning by the laser beam is in one Method of moving a laser device by means of a Scanners and in a method of deflecting the laser beam divided by a laser device.

While the present invention applies to both of the above written procedure is applicable, the procedure of Driving the wafer and the object table together for the scan is used in the following outline.

In the process of mechanical or mechanical Marking processing of the stage control type becomes a on an object table, which is on an X-Y scanning device device (scanner) is attached, placed wafer in X and Y direction moves while a laser device is over the  Stage is set, and it becomes the top surface surface of the wafer with one emitted by the laser device th laser beam irradiated so that a continuous on cracked groove is formed on the moving wafer where separated by chips along the torn grooves the.

The X-Y scanner on the stage will controlled by the scan control device, which with ei computer that is suitable for numerical control, is provided and position control of the X-Y scan direction according to the coordinate data, wel che have been entered. The scan control device be sits a monitor, which is used to display images particular of coordinates to which the computer is connected and a position detection device for detecting the Wafers on the stage and to display the wafer on the monitor. For the position detection device usually to display the wafer on the monitor and especially for displaying the two positioning marks which have been grasped and the image of the angeris groove on the coordinate plane of the scanning control direction which has been formed in advance for ver used a video camera.

First embodiment

In the method of separating chips from the semiconductor wafer according to the present invention, an XY coordinate system as the XY plane on the top surface of the wafer in the scanning control as shown in Fig. 1A and Fig. 1B defined. For example, the origin 0 of the XY coordinate system is related to the center of the wafer, while the X axis is related to the longer side of the chip to be separated and the Y axis is determined perpendicular to the X axis. The X axis and the Y axis can be interchanged.

In step a), cutting pitch Px and Py along the X-axis and the Y-axis, which correspond to the dimensions of a chip on the semiconductor wafer, are input to the scan control device. Typically, the length of the chip 4 is along the longer side as Ra sterabstand Px in the X direction and the length of the chip 4 ent long Y-direction of the shorter side taken as a pitch Py in. These grid spacings can be dimensions of a chip. This enables a large number of imaginary tear lines 2 ( 21 , 22 ), which are drawn at right angles to one another onto the coordinate plane, as a result of which the coordinates of the intermediate sections of the lines which have been scribed are determined.

In step b), coordinate values of a non-marking line area of the scanning control device for the imaginary marking lines 2 ( 21 , 22 ) are input, which have been defined by the input in the previous method. The coordinates are determined not by determining the imaginary scribe lines to be machined or mechanically but by determining the area of the imaginary scribe lines not to be machined or mechanically. The area of the marking lines is usually defined by the marking line in the direction of the X axis and the marking line in the direction of the Y axis by entering the coordinates 21 (x, y), 21 (x, y) of the intermediate sections of the marking lines.

The wafer is then placed in a specific position on the wafer Object table placed and fastened in the meantime.

In step c), a laser beam scans the semiconductor wafer 1 at the determined raster distances along either the X or the Y direction, for example it first performs a scan along the direction of the X axis ( FIG. 2 (A)) with the determined pitch and thereafter a scan along the direction of the Y axis ( Fig. 2 (B)) in the determined pitch by the scan control direction. During this scanning process, the machined scribing line areas 21 a, 22 a are not irradiated by the laser which is switched off, while the laser beam is switched on at the irradiation position 90 in the scribing line regions 21 b, 22 b, which is not are determined, whereby grooves are formed on the scribe lines of the semiconductor wafer.

In the scanning step c) of this embodiment, the optical axis of the laser beam essentially in the right Angles aligned with the wafer surface, and the Ab Key control device controls the position of the X-Y scanning device such that the X-Y scanner Semiconductor wafers in two dimensions along the X direction and the Y direction.

In this case, as shown in FIG. 2A, the first scan is carried out in the direction of the X axis, the optical axis 90 of the laser beam extending in the direction of the X axis over the wafer from a starting point 91 a, which is at the tip of the located on the left outside of the wafer 1 is repeatedly moved while scanning in the Y-axis direction from one end (one of the edges) at a certain pitch across the center to the other end (the other edge) is repeatedly performed, whereby one track of a large number of parallel marking lines is successively followed in the direction of the X-axis and possibly the end point 92 a is reached.

Thereafter, the laser beam scans along the direction of the Y axis, and the optical axis 90 of the laser beam is repeatedly moved in the direction of the Y axis across the wafer from a starting point 91b at the lower right end while scanning in the direction of the X-axis from one end (one of the edges) at a predetermined grid spacing across the center to the other end (the other edge) is repeatedly performed and a large number of parallel scribe lines successively in the direction of the Y -Axis is followed until end point 92 b is reached.

When scanning in the direction of the X axis, the large number of parallel marking lines 21 in the direction of the X axis are irradiated except for the specific region 21 a with the laser beam to form marking grooves 31 , and when the next scanning in the direction of the Y axis Axis is carried out, the existing in the large number of parallel marking lines 22 in the direction of the Y axis except in the specific region 22 a with the laser beam to form scribing grooves 32 be irradiated. In this way, a part which is surrounded by the tear grooves 31 , 32 which cross each other in the X and Y directions is separated as a chip 4 .

This embodiment further includes a method for correcting the deviation between the XY coordinate system, which is formed by the scanning control device on the object table, and the X'-Y 'coordinate system on the wafer 1 .

For the purpose of correcting the coordinates, the steps described below are carried out before the load step c). The method including the method of correcting the coordinates is shown in the flowchart of FIG. 4, and the method of correcting is shown in FIG. 3.

In step d), as shown in Fig. 2, X and Y coordinates (X'-Y 'coordinate system on the wafer) of the two positioning marks Ma, Mb on the semiconductor wafer 1 of the scan control device are input in advance. For example, for the two positioning marks Ma, Mb, printed alignment marks are used in a particular chip.

In step e), as shown in FIG. 2, two positioning marks Ma ', Mb' (alignment marks) on the semiconductor wafer 1 , which is attached to the specimen stage, are detected by the position detection device, as a result of which the coordinates of the markings from the perspective of the specimen table ( XY coordinate system of the stage) are determined, which are entered into the scanning control device.

For the position detection device is more common assign a video camera to capture the image of the wafer used, which is displayed on the monitor. The two Position marks are made with the coordinates of the Scan control device, namely the coordinates of the Ob ject table compared, which in advance on the monitor have been set, and will be the scan controller entered.

In step f), the determined coordinates Ma, Mb of the marking on the wafer and the detected coordinates Ma ', Mb' of the marking from the viewpoint of the object stage are compared by displacements Δx, Δy in the X direction and Y direction and to calculate the angle of rotation θ of the wafer coordinates in relation to the stage coordinates (which are also the scanning coordinates of the laser beam). These data are used in the coordinate conversion of the imaginary scribe lines 21 into the wafer coordinates from the point of view of the object table coordinate system, whereby the equation of the imaginary scribe lines 21 'from the point of view of the converted object table coordinate system (XY coordinate system) is formulated.

In step g), the optical axis of the laser beam can follow a trace across the scribe lines on the current wafer in the case where the stage corresponding to the equation of the imaginary scribe lines after the conversion in the method of forming the grooves by scanning the Laser beam is scanned in step c), and there are suitable grooves by irradiation with the laser beam in the marking line area, which was not determined, without deviation from the marking lines leading to the chip 4 , through the series of operations in the Step c) formed.

Because the angle of rotation θ of the placed on the stage Wafers in the process of scanning by the laser beam can be corrected, a setting of the spin kels θ by rotating the wafer or the stage like not required in the prior art.

Fig. 4 is a flowchart showing an example of this embodiment. In the first step of this method, after inputting the X-direction and Y-direction raster distances of the scanning controller, imaginary scribe lines are formed, and a non-scribe line area is formed on the scribe lines in FIG X direction and Y direction determined, and then the coordinates of the positioning marks are entered.

In the next step, the wafer is on the object placed and fastened table, it becomes the positioning mark on the upper surface of the wafer from the Erfas solution device with the entered coordinates in the Wafer coordinate system is detected and it becomes at the time  point to which the coordinates are corrected, the Equation of the marking line from the perspective of the stage coordinator natensystem determined.

The next step is the optical axis of the Laser beam of the trace of the marking line by scanning in X- Direction of the stage. The scribe line in the X direction except the non-scribe line area is laser beam irradiated.

After scanning in the X direction, the marking line becomes Y direction irradiated with the laser beam.

At the end of this process, the chip is separated.

Second embodiment

In this embodiment, the step of Enter the grid spacing in step a) entering the block spacing of two or several chips, creating a block area in the coordina ten level is formed.

In step a), the cutting grid spacings are removed along the X axis and the Y axis, which correspond to the dimensions of a chip on the semiconductor wafer correspond to Ab key control device entered. In this step Grid spacing as a block grid spacing, which is two or includes multiple chips to form two or more block areas on the coordinate level.

Each block is determined in such a way that it is suitable contains the number of chips by entering the block stands in the X direction and the block grid spacing in Y-Rich tung.  

In each block, the length of the chip is along the longer side than grid spacing in the X direction and the Length of the chip along the shorter side as a grid stood taken in the Y direction. These grid spacings can the dimensions of a chip. This enables a large number of imaginary scribe lines, which are are at right angles to each other on the Koor to draw the plane of the data, whereby the coordinates of Zwi sections of the marking lines can be determined.

In step b) coordinate values become a not marking line area of the scanning control device for the imaginary scribe lines, which are entered by entering have been defined in the previous step. Of the The area of the marking lines is first determined by determining the Blocks and then by entering the coordinates of the To tear line area in the direction of the X axis and the marking line area defined in the direction of the Y axis.

The formation of the block area is to determine the Non-scribe area advantageous. In the case at which in particular a wafer has 100 grid spacings in X Direction (100 marking lines in the X direction) and 200 grid would appear in the Y direction (200 marking lines in the Y direction) holds, the coordinates are ge in the unit of blocks counts, and there may be errors when entering the Koor dinates can be effectively prevented. In a similar way a chip that has two positioning marks, can also be easily determined.

The subsequent step (C) can be done in a similar manner as in the case of the first embodiment become.

Third embodiment

This embodiment provides a method for determining the coordinates of a large marking area in the Step of determining the non-scribe line area in the Step b) ready.

I.e. the non-scribe area is considered to be more spacious Area before determining the area on the scribe lines certainly. By viewing the area outside the designated th area as the non-scribe line area can be wide sluggish operation of determining the coordinate values in omitted in the case of a large non-scribe area become.

In this embodiment, the following steps carried out.

In step a), the cutting grid spacings are removed along the X axis and the Y axis, which correspond to the dimensions of a chip on the semiconductor wafer correspond to Ab key control device entered. The length of the chip long the longer side is called the grid spacing in X-Rich tion and the length of the chip along the shorter side than Grid spacing taken in the Y direction. This grid stands can be the dimensions of a chip. Thereby it is possible that a large number of imaginary An tear lines, which are at right angles to each other are drawn on the coordinate plane, whereby the coordinates of intermediate sections of the marking lines can be determined.

In step b), coordinate values of a non-marking line area of the scanning control device for the imaginary marking lines are input, which have been defined by input in the previous step. In this embodiment, the coordinates are determined for one or more long-range marking areas which contain one or more chips with respect to an area which is surrounded by a closed line determined by the coordinates. For example, in the case where the area is rectangular as shown in Fig. 5, four coordinates 30 a, 30 b, 30 c, 30 d of the four vertices are determined. However, the wide scribing area is not limited to a rectangular structure and can be formed as a polygon with a step or cross shape, the coordinates of the outer corners 301 and the inner corners 302 of the profile being determined.

Imaginary scribe lines outside the wide scribing area 30 are defined as those that are not mechanically or mechanically processed. In contrast, it is practical to define all scribing lines on the inside which are to be machined or machined. While the attribute of a scribe line can be defined as being required in a case of a line segment defined by two sets of coordinates which define an area corresponding to an imaginary scribe line, it is convenient to machine the line segment mechanically. In this case, all marking lines within the wide marking area are processed mechanically or mechanically. Thus, if the wide scribing area further includes a non-scribing line area, this area is determined again by entering the coordinates thereof.

The non-scribe area is convenient if an area of unnecessary chips that is near the edge of the semiconductor wafer or an area outside of theo achievable chips that ge on the semiconductor wafer forms, are localized, can be excluded. When a 2 inch wafer is processed on a device that is suitable for cutting from a 4 inch wafer, it is for example, the entire area outside the 2-  To determine inch wafers as the non-marking area. At this embodiment suffices, however, only the Be of the 2-inch wafer on which the chips are essentially Chen are formed as a large marking area to determine what will make it possible to spread the word operation of determining the non-scribe area to avoid in the outer area.

The spacious marking area also makes it unnecessary to determine a non-scribe line area if a times a wide marking area is determined, if the Non-scribe area has a large area where with no chip cut from the wafer. One more Number of large marking areas can be on the Koordi be determined at national level. One day, the spacious An tear area which has been determined with a laser beam irradiated and cut into chips.

Furthermore, determining a wide range can tear area used when determining an area that which contains a plurality of chips and can also used to determine only one chip become.

In step c) the optical axis of the laser beam scans the semiconductor wafer 1 in the determined raster distances either along the X or the Y direction, for example there is first a load along the direction of the X axis in the determined raster distance and then a scan along the direction of the Y-axis in the certain raster distance be performed by scanning the object table controlled by the XY scanning device and the control of the scanning control device. During this scanning step, the marking lines are regarded as the non-marking line area and are not irradiated by the laser, which is switched off when the optical axis of the laser beam is outside the wide marking area. When the laser beam performs a scan within the wide scribing area, the laser is turned on so that the scribe lines are irradiated with the laser beam and grooves are formed. However, an area in which a non-scribe line area is determined is not irradiated with the laser beam within the wide scribe area, which is turned off. Thus, the inside of the wide scribing area on the wafer other than the non-scribing area is cut into chips along the scribing grooves, while the area outside the wide scribing area remains without mechanical or machining.

Fourth embodiment

In the fourth embodiment, the method of above embodiment twice or more for a half conductor wafer repeated. In this embodiment from the same semiconductor wafer as that through these steps cut chips other chips further by the Steps separated. This is for the purpose of processing of the semiconductor wafer from which the chips in the process ren of the previous embodiment to separate the remaining chips, which are before were not processed outgoing.

Such a method is used as the first example wrote, which is used in a case where wel chem a semiconductor wafer two or more types of chips with different dimensions, especially on it contains ordered grid spacings.

In the first separation process, first cuts are made spacing along the X-axis and the Y-axis, wel che correspond to the dimensions of the first chip, the Ab  key control device in the grid spacing input step a) entered. Coordinates of the intermediate sections of the imaginary Ren marking lines are defined on the coordinate plane. In step b) all areas outside the Ge in which the chips of the first type are arranged, considered as non-marking areas, and the Koordi Data values of the non-scribe area become the sample control device for the imaginary scribe lines ben by entering in the previous step have been defined. In step c) the opti gropes cal axis of the laser beam into the semiconductor wafer most cutting grid spacings first along the X-Rich and then along the Y direction. During this The non-marking area is not included in the scanning step irradiated to the laser, which is switched off during the Laser beam is switched on in the marking line areas, which are not determined, namely in the area in which chem the chips of the first type are arranged, whereby the Chips of the first type from the semiconductor wafer by laserbe radiation and a wafer with chips of the second type remains on it.

In the second separation step, second cuts are made spacing along the X-axis and the Y-axis, wel che correspond to the dimensions of the second chip, the Ab key control device in the grid spacing input step a) entered. In step b) all areas are except half of the area where the chips of the second type are on are classified as non-scribe area, and the coordinate values thereof become the scanning controller tion for the imaginary scribe lines. By doing Step c) introduces the optical axis of the laser beam Scanning the semiconductor wafer in the determined second Cutting grid spacing first along the X direction and then along along the Y direction. During this scan The non-marking area is not gradually increased with the  Laser irradiated, which is switched off during the La beam in the undetermined marking line areas is switched, namely in the area in which the Chips of the second type are arranged, making the chips the second type of semiconductor wafer by laser irradiation can be separated, creating the chips of two types be separated.

In the case where the wafer is more than two types of chips formed on it with different raster stands, the separation operation described above on repeated according to the number of types of chips.

The next example is a step for a case in which a semiconductor wafer has two types of Chips of different dimensions or different Contains grid spacings that are arranged on it.

In the first separation step, after entering the first cut grid spacing along the X axis and the Y axis, which is the dimensions of the first type of chip correspond to the scan controller in the raster Stand input step a) the coordinates of the intermediate cut the imaginary scribe lines in step b) given the area where the chips of the first Are arranged to de as a spacious marking area finish. In step c) the optical axis of the Laser beam over the semiconductor wafer by means of the scan control device in the first cutting grid intervals for example, first along the X direction and then along the Y direction. During this scanning step tes become areas outside of the spacious marking area Reichs not irradiated with the laser, which is switched off is while the laser beam is within the wide range tear area is turned on, causing the chips of the he most kind of the semiconductor wafer by laser irradiation  be separated and a wafer with remaining on it Chips of the second type is formed.

In the second separation step, after entering the second cut grid spacing along the X axis and the Y-axis, which correspond to the dimensions of the second chip type correspond to the scan controller in the raster Stand entry step a) Coordinates of the intermediate sections the imaginary scribe lines entered in step b), around the area in which the chips of the second type are indicated are to be defined as a wide marking area. The optical axis of the laser beam leads in step c) a sampling of the Semiconductor wafers in the specific second clipping grid distances first along the X direction and then along the Y direction. During this scanning step Areas outside the wide marking area are not irradiated with the laser, which is turned off while the laser beam in the marking line areas, which are not are determined, is turned on, namely in the Weiträumi scribe area, which makes the chips of the second type of who separated the semiconductor wafer by laser radiation which separates the chips of the two types.

Such separation operations are carried out according to the Number of chip types with different grid spacings repeated.

Fifth embodiment

In this embodiment, the semiconductor wafer is provided with grooves, namely scribing grooves, which are formed on the scribing lines along which the wafer is broken into chips in advance in the separation step described above. As shown in Fig. 6 (A, B), the scribing grooves 20 are formed by removing a narrow strip of a semiconductor layer 12 of the semiconductor wafer 1 by etching, while an electrode metal layer on the back of the semiconductor wafer remains as the bottom of the groove. The mechanical or mechanical processing rate by laser irradiation of the semiconductor wafer, which has the scribing grooves formed thereon, can be increased if the semiconductor layer has been removed. Since, as in another application (Japanese Patent Application No. 8-173960), the electrode metal layer 11 which forms the bottom of the scribe groove, for example a layer of gold or an alloy thereof, highlights a high reflection coefficient with respect to a laser beam and accordingly a low tendency to heat shows, a metal layer 23 having a high reflection coefficient with respect to a laser beam which is stacked along the scribe groove is used as the bottom of the groove. Ni can be used for the metal layer 23 . Grooves are preferably also formed on the back of the electrode metal layer 11 , whereby parts of the electrode metal layer 11 which are to be irradiated with the laser beam are made thinner and thus make it possible to further improve the machining rate by the laser beam.

By forming the scribing groove 20 , which is covered with a Ni layer as the metal layer 23 , on the scribing lines on the top of the semiconductor wafer in advance, the rate of mechanical processing with the laser beam can be increased significantly, thereby making the chip detaching operation more efficient is made.

For this purpose, the semiconductor layer 12 is etched on the scribing lines between circuit elements along which the semiconductor wafer is to be separated to form grooves, after which the metal layer on the bottom of the grooves with the Ni layer 23 is deposited by vapor deposition or a similar step Formation of the scribing grooves 20 covers, and then the method of chip removal according to the first or fourth embodiment is applied. The scribe grooves 20 as described above can be applied to all of the methods of the present invention.

The chip removal method of the present Er invention for the purpose of separating desired chips from the semiconductor wafer by irradiating the wafer with a Laser beam, which is used for scanning in the direction of an X- Axis and a Y axis by means of a scanning control device device is controlled, contains the steps a) entering the Cutting grid spacing along the X-axis and the Y- Axis corresponding to the dimensions of chips, b) Be agree the coordinate values of a non-marking line reichs and c) scanning by the laser beam of the half lead terwafers in the specified grid spacing in X or Y Direction under the control of the laser beam scanning control device during the irradiation of the marking lines except the non-scribe line area, whereby grooves are formed which and the wafer is cut into chips. Therefore, egg a large number of chips quickly and efficiently the one without which a single determination over a broad ge offers.

Since in the method of the present invention the Ra star distances are entered as block grid distances, which each contain two or more chips to blockge offer on the coordinate level in the grid spacing input it is easier to define the knockout ordinates of the non-scan line area in the subsequent to determine the necessary step, and it will continue easier, coordinates of two positioning marks to determine and record. Because according to the procedure of the present invention the coordinates of long-range  Marking areas in the step of determining the non-marking tear line range can be determined, a separation of Chips from a certain area easier by a Ab can be performed by the laser beam, and it can more easily identify chips of two or performed more types of different grid spacing which makes it possible to quickly and efficiently ne small number of chips of different types, which on the wafer are arranged to separate. Because the spacious Marking area can be determined such that an area of unnecessary chips, which are near the edge of the half lead terwafers are localized, or an area outside theoretically achievable chips on the semiconductor wafer area formed, excluded, can be a wide rambling operation of determining the non-scribe lines be canceled.

Since according to the method of the present invention the wide scribing area in chip units can be voted and can be determined such that he contains a plurality of chips, an operation of the Scanning a single chip on the wafer very easily be made.

The method of the present invention may relate to of a wafer can be repeated two or more times and is for the separation of chips of different structure effective.

Furthermore, the method of the present Invention by determining the coordinates of two positions marking marks on the semiconductor wafer and by Er grasp the marks on the wafer on an ob ject table is attached by coordinate conversion allows the laser beam to scan in one Direction with the X-axis and Y-axis rotated one turn  are tilted in step c) the formation of the Ril len performs, making a fine adjustment of the Waferwin kels on the turntable is no longer required.

Because the semiconductor wafer with scribing grooves for separation of chips formed on it is provided in advance and ins special the bottom of the scribe grooves with a metal layer is covered, which is a high efficiency of the absorber has a laser beam, a marking opera tion faster using the laser beam the, which makes the process by improving the operations efficiency is made more effective.

A method of cutting a Semiconductor wafers disclosed in chips, which is efficient Specify coordinates to cut a large one Number of chips from the semiconductor wafer during doughing eats a large number of functional elements such as semiconductor circuits formed with the semiconductor wafer the laser beam as part of a semiconductor production is suitable. The chips are separated by mistake Scanning control device with cutting spacing ent along an X axis and a Y axis, by determining the Coordinate values of a non-marking area for ima generic marking lines with respect to the scanning control device, while the scan controller is performing a laser beam scan of the semiconductor wafer in the specified grid spacing along the X direction and then along the Y-Rich practicing; the marking is thus irradiated lines performed except on the non-scribe area, thereby forming grooves and the wafer in chips will cut.

Claims (10)

1. A method for separating desired chips from a semiconductor wafer by irradiating the wafer with a laser beam, the optical axis of which for scanning the XY plane is controlled by a scanning control device which carries out a numerical control of the scanning position, with the steps:
Entering a scan control distance along an X-axis and a Y-axis, which correspond to the dimensions of chips on the semiconductor wafer, of a scan controller;
Determining coordinates of a non-scribe line area with respect to the scan controller for imaginary scribe lines formed in the step of inputting the pitch; and
Forming scribe grooves by irradiation with a laser beam of scribe lines other than the specified non-scribe line area, the scan control means performing a scan of the optical axis of the laser beam over the semiconductor wafer at the specified pitch along a direction of the X and Y directions, and then optical Axis performs a scan in the other direction at the determined grid spacing, whereby the chips are separated. 2. The method according to claim 1, characterized in that the step of entering the grid spacing comprises the steps:
Entering block unit grid spacings of a block containing two or more chips that form a block area on the coordinate plane; and
then enter the clipping spacing within the block area. 3. The method of claim 1, characterized in that the step of determining the non-scribe area includes determining the coordinates of one or more wide-area scribing areas containing one or more chips and determining the non-scribing area in each of the wide-area scribing areas; and
the entire area outside of the wide marking area is defined as a non-marking area. 4. The method according to claim 3, characterized in that the wide marking area is determined in such a way that an area of unnecessary chips that is close to the Edge of the semiconductor wafer are localized, or a Be rich outside of theoretically achievable chips that are based on the semiconductor wafer are formed is excluded. 5. The method according to claim 3, characterized in that the spacious scribing area in the unit of chips is determined. 6. The method according to claim 3, characterized in that the wide marking area is determined in such a way that a plurality of chips are included. 7. The method according to claim 1, characterized in that of the same wafer from which by the steps Chips have been separated by the steps of others Chips are separated. 8. The method according to claim 1, characterized by the further steps:
Determining the coordinates of two or more positioning marks on the semiconductor wafer with respect to the scan controller in advance;
Detecting the two or more positioning marks on the semiconductor wafer, which is attached to the object table, by means of a position detection device, whereby the XY coordinates of the marks are determined;
Comparing the coordinate data of the marks where detected by an angle of rotation of the coordinate axis with respect to the wafer; and
Scanning in directions with the X direction and the Y direction tilted by the angle of rotation in the step of forming the grooves by laser beam scanning. 9. The method according to claim 1, characterized in that the semiconductor wafer with scribe grooves formed therein is provided in advance to separate the chips. 10. The method according to claim 9, characterized in that the scribe grooves are formed with one on the floor The metal layer is covered, which is a greater efficiency Has ciency of laser beam absorption.