JPS6134955A - Automatic separation of silicon wafer - Google Patents

Abstract

PURPOSE:To equidistantly arrange separated chips for easer identification and takeout by a method wherein a constant pressure is caused to be present on a wafer after provision of grooves by ensuring that the pressure exerted by a brake roller upon the rear surface of a wafer is increased or decreased in proportion to the area of contact. CONSTITUTION:A slice protecting sheet 6 is applied to the upper surface of a silicon wafer 1 installed on an adhesive masking sheet 7, the silicon wafer 1 is protected by urethane rubber constituting the lower portion of the ceiling of a brake roller, and a Y-axis brake roller 10 is rotated to move forward, from the lower surface of the masking sheet 7 on the rear surface of the silicon wafer 1, exerting pressure for the separation into a plurality of pieces of the silicon wafer 1 along scribe lines. The pressing force exerted by the Y-axis brake roller 10 upon the rear surface of the silicon wafer 1 is accurately adjusted to increase or decrease in proportion to the area of contact with the silicon wafer 1. The most suitable changes in the pressing force are determined by a prior test and the results are stored in a memory, to be outputted for automatic control.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is directed to Ice, LSr, super, 5Ilt (1
) This is a method that automatically separates the stacking board (silicon wafers) at equal intervals to make it easier to take out each chip, and is used in the field of silicon wafer assembly technology.

(Prior art) Conventionally, before chip-ponding a silicon wafer with scribe lines and vertical and horizontal grooves (half-cuts) as shown in Fig. 4, this silicon wafer placed on a sheet was used as a chip. To separate the chips, a skilled worker presses and rotates a rubber roller parallel to the scribe line from the back side of the wafer sequentially in the vertical and horizontal directions (X-Y directions) to separate the chips, or a thin diamond wheel is rotated at high speed. The silicon wafer is then diced, cut across the entire surface, separated into individual chips, and the sheet on which these separated chips are placed is manually expanded to increase the spacing between the chips and make it easier to recognize each chip. (Problem to be solved by the present invention) In the above-mentioned conventional technology, the premise of Guiponding is to ensure that each chip is spread out at equal intervals in order to recognize and take out the separated chips. There were difficulties.

In other words, in order to solve the above-mentioned difficulties, it is necessary to reliably separate the silicon wafers placed on the sheet into chips at equal intervals without causing any deviation in the arrangement, and to ensure that the entire sheet is expanded uniformly. . However, when using a manual method in which a skilled worker presses and rotates a rubber roller from the back side of a silicon wafer, for example, the silicon wafer is semicircular with a partially cut-out orienteering flat part, so chips around the chip may be damaged. In order to separate chips while avoiding deterioration of the yield rate due to The pressure applied to the rubber roller itself had to be increased or decreased accurately, which required considerable skill.

It is said that at least three months of training is usually required to master this change in pressure, but no matter how skilled the operator is, it is important to avoid changes in concentration from time to time. Some unseparated chips may remain. In this case, no matter how uniformly the sheet is expanded, unseparated portions remain, so even if the sheet is expanded, the purpose of easily recognizing and taking it out during pounding cannot be achieved. Also,
Even if the unseparated half-cut portions are pressed separately with a spatula to separate them individually, it requires extremely advanced techniques to apply enough pressure to separate the chips without causing damage, and unnecessary pressure may cause the chips to separate. Even if the sheet is adhered to the sheet, it is inevitable that misalignment will occur, and it may also cause partial dents or scratches on the sheet, so even if you try to spread the sheet uniformly, the sheet itself will be distorted, etc. Therefore, the main purpose of spreading the chips at equal intervals cannot be achieved. Furthermore, the method of cutting the entire surface by dicing inevitably damages the sheet surface, so even if you try to expand the sheet, it will break, making it impossible to achieve the goal of separating the chips at equal intervals on the sheet and making it easier to take them out. It will also be difficult.

It should be noted that it would be possible to increase the probability of recognition and selection by using a highly advanced Guibonder's external shape recognition function during Guibonding to deal with the distortion of the arrangement caused by manual separation using rubber rollers. The Guibonder becomes extremely expensive and becomes economically uneconomical.

Next, even if the chips are separated without disrupting the arrangement, which is the main part and premise of the present invention, it is not possible to separate and arrange the chips at equal intervals unless the sheet is expanded completely uniformly. However, it is impossible to manually expand the sheet on which the silicon wafer is placed evenly on a Uniper holder and lock it in the expanded state with an O-ring because the chip spacing is extremely narrow. I can't wait.

(Means for Solving the Problems) In order to achieve the purpose of separating silicon wafers on a sheet into chips and arranging the chips at equal intervals as a premise of Guiponding, in order to easily recognize and take out the chips, in the present invention, During chip separation, the roller rotation direction and the scribe line are automatically controlled by a sensor to make them completely parallel, and the pressure applied from the roller to the back surface of the silicon wafer is automatically increased or decreased according to the diameter of the silicon wafer via a storage device. A method was adopted in which the temperature was controlled and kept constant, and the chips on the sheet were completely separated without any unseparated portions, and the separated chips were not misaligned on the sheet. In addition, while using this method as the main part, when expanding the sheet, the wafer holder is pushed up from the bottom of the sheet with a table lifter while the sheet on which the separated chips are placed is pressed from above with a cylindrical sheet stopper, and the top of the wafer holder is pressed. In this state, the O-ring is mechanically rolled down from the top surface of the wafer holder using a cylindrical ring pusher. At this time, the sheet is further expanded and the O-ring on the side of the wafer holder is rolled down. This method uses a method to achieve the purpose of automatically arranging the separated chips at equal intervals by cutting the periphery in one step after inserting the O-ring into the groove.

(Embodiment) A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a device which has put the method of the present invention into practical use and can be called a break expander, and FIG. 2 shows the main part of the operating process of this device.

The silicon wafer 1 just before being separated by the rollers is sandwiched between the masking sheet 7 on the back side and the slice protection sheet 6 on the top side as shown in FIGS. 2 and 3. To explain this, as shown in FIG. 2, one silicon wafer l out of the required number set in the slice cassette 2 is sent out by the delivery conveyor 3, and is orienteering flat by the sensor by the facet and top alignment 4. After detecting and positioning the portion 1', the wafer positioning pusher 5
By pushing out the front part of the wafer, the front part and the orienteering flat part 1' are brought into alignment with each other as shown in FIG. At this time, the silicon wafer 1 is placed a on an adhesive masking sheet 7, and by movement of the masking sheet 7, it is positioned above the Y-axis break roller IQ. At this stage, as an extension of the pushing of the wafer positioning pusher 5, the fourth
The horizontal groove 1d2 along the scribe line of the silicon wafer 1 shown in the figure is parallel to the rotational forward direction of the Y-axis break roller 10.

In this state, a slice protection sheet 6 is placed on the top surface of the silicon wafer 1, and the lower part of the break roller receiving plate 8 is made of urethane rubber to protect the silicon wafer 1 while the third
As shown in FIG. 4, if the Y-axis break roller 10 is rotated forward and pressed from the bottom surface of the masking sheet 7 on the back surface of the silicon wafer 1, the silicon wafer 1 will have a wafer thickness of 1 tl, as shown in FIG. On the other hand, there are already longitudinal grooves 1dl and horizontal grooves 1d2 along the scribe line, and there is a remaining plate thickness 1t2 on the groove side, so as shown in FIG. A fracture gap 1d4 is generated along the vertical groove 1dl due to the pressing force from below of the Y-car break roller 10 (not shown). At this time, in order to ensure complete separation with one press, avoid chipping around the chip, and increase the yield rate, it is necessary to reduce the pressing force from the Y-axis break roller IO to the back surface of the silicon wafer 1. Since the increase/decrease must be accurately adjusted and kept constant in proportion to the contact area with the silicon wafer 1, the best results of this change in pressing force are pre-tested and stored in a storage device for automatic control. It is. In such a method, since the pressing force on the remaining board thickness 1t2 on each groove side of the back surface of the silicon wafer l is constant, no misalignment of the chips occurs after the chips are broken and separated.

In addition, compared to conventional manual methods, this method saves one-third to one-fourth of the time, and the yield rate of expensive chips is close to 100%.

After passing through this process, the masking sheet 7 is further advanced, and this time, the silicon wafer 1 is rotated forward at right angles to the rotational advance direction of the Y-axis break roller IO, and is rotated forward and pressed by the X-axis break roller 11, which performs the same function. A break line is inserted along the horizontal groove 1d2, and each chip is separated from each other, and no deviation occurs in the arrangement. Note that in this example, Y
The axis break roller 10 is rotated forward first, but the X axis parallel to the orienteering flat 1' is
A method may also be used in which the shaft break roller 11 is rotated and advanced first.

In this state, each chip is separated for the time being, but when bonding, it is difficult to recognize the very thin groove with the die bonder's external shape recognition device and take out the chips one by one. To do this, the masking sheet 7 on which the separation chips are placed needs to be spread outward evenly from the vicinity of the center of the silicon wafer.

Therefore, the masking sheet 7 on which the finely divided wafers 1a' are placed is moved, and as shown in FIG. The center of the divided wafer 1a' is positioned (the slice protection sheet is removed in this process), and the O-ring 17 is moved from the O-ring stocker 16 to the O-ring catcher as shown in FIGS. 6 to 9. Move to O-ring expander 19 via 18.
- Expand the O-ring 17 with the required number of O-ring expanders 19 that slide outward in a radial pattern, and temporarily place the O-ring 17 under the cylindrical O-ring stopper 20 that has descended to the center. Fit this 0 ring 1
The fitted O-ring stopper 20 of No. 7 is moved again and automatically positioned above the cylindrical seat receiver 30. And as shown in FIGS. 10 to 13, 0
The sheet stopper 27 slidably attached to the outer periphery of the ring stopper 20 is lowered, and the masking sheet 7 is pressed between the lower end of the sheet stopper 27 whose tip is made of silicone and the upper end of the seat seat 30. At this time, the masking sheet 7 is cut by a masking sheet counter 22 at the rear thereof, as shown in FIG.

Next, the wafer holder 13, which has a diameter smaller than that of Zitos)-/Par 20, was pushed upward by the table lifter 28 to spread the masking sheet 7 evenly outward from the center, and the wafer holder 13 was separated as shown in FIG. Breaking gap 1d in chip
4, and in this state, as shown in FIGS. 15 and 16, the ring stopper 20 is lowered to land on the wafer holder 13 of the same diameter, and then the 0 ring 1
When a cylindrical ring pusher 28 with an inner diameter slightly smaller than the outer diameter of the masking sheet 7 is lowered into contact with the O-ring 17 and rolled from the upper outer periphery of the wafer holder 13 and lowered, the masking sheet 7 is further expanded to an average level and then the O-ring An O-ring 17 is fitted and fixed in the groove 13'. The inner diameter of the ring pusher 29 is as shown in FIG.
The outer diameter of the O-ring 17 is larger than that of the O-ring 17 that is fitted and fixed on the ring, and it does not come into contact with the O-ring 17.
As the ring pusher 29 continues to descend, the masking sheet 7 is cut into a circular shape by the cutting edge of the ring cutter 21 fixed to the outer surface of the ring pusher 29 in a cylindrical shape, thereby completing a wafer holder used in the guide bonding process.

(Effects of the Invention) Since the present invention has the above-described configuration, (1) silicon wafers placed on a sheet can be automatically and reliably separated into chips at equal intervals, and (2) extremely Since they can be functionally separated, labor, cost, and time can be greatly reduced; (3) the yield rate during chip separation can be significantly improved; The practical effects in the field of manufacturing and assembly technology for integrated circuits, which have been in the spotlight in recent years, are truly great, such as making the mounting process much easier and cheaper.

[Brief explanation of drawings]

1 is a perspective view of an overall assembly of an apparatus embodying the present invention; FIG. 2 is a perspective view of the entire main part of the apparatus; FIG. 3 is a perspective assembly view of a wafer dividing apparatus embodying the main parts of the invention; Figure 4 is a perspective view of the silicon wafer, Figure 5 is a diagram explaining the functions of the silicon wafer, Figure 6 is a diagram explaining the O-ring setting,
Figure 7.8.9 is a diagram functionally explaining the process from taking out the O-ring to installing it on the O-ring stopper.
The figure shows how to install the O-ring and how to cut the masking sheet. Figure 11 is a silicon wafer introduction diagram. Figure 12
The figure shows the inserted state of the masking sheet, Fig. 13 shows the expanded state of the masking sheet, and Fig. 14 shows the masking sheet inserted.
3, FIG. 15 is a diagram showing the rolling state of the O-ring, and FIG. 18 is a diagram showing the masking sheet cart/cart. ■...IC1l board (silicon wafer), 1'...
Orienteering flat, 1a, 1al~Ia8・
...chip, laζ...segmented wafer, Idl
... Vertical groove, 1d2... Horizontal groove, 1d3... Breaking line, 1d4... Breaking gap, Itl... Wafer plate thickness, 1t2... Remaining plate thickness after groove side, 2... - Slice cassette, 3... Delivery conveyor, 4... Facet prealignment, 5... Wafer positioning pusher, 6... Slice protection sheet, 7... Masking sheet, γ... Stretched masking Seat, 8・
...Break roller receiving plate, 9...Sheet winding reroll, 1°...Y-axis break roller, 11...
X car break roller, 12... wafer holder stocker. 13...Wafer holder, 13'-...0 ring groove,! 4... Feed conveyor, 15... Feed lifter, 16... O-ring stocker, 17...
0 ring, 17', 171'...Expanded 0 ring, 18...0 ring catcher-119...0 ring expander, 20...0 ring stopper, 2
1... Ring cutter, 22... Masking sheet cutter, 23... Delivery conveyor, 24...
Feeding lid 125...Completed wafer cassette,
26... Slice cassette, 27... Seat stopper, 28... Table lifter, 29... Ring pusher, 3o... Seat catch.

Claims (1)

[Claims] 1. A silicon wafer is placed on a masking sheet so that the orienteering flat part of the silicon wafer is located perpendicularly or parallel to the rotational forward direction of the Y-axis break roller, and a slice is placed on the top surface of the silicon wafer. Apply a protective sheet, and then apply a break roller receiving plate from the top of the slice protective sheet.
The pressing force from the Y-axis break roller on the back surface of the silicon wafer is automatically controlled using a memory device and made proportional to its contact area so that the pressing force on the remaining plate thickness portion after each groove cutting of the silicon wafer is constant. Increase or decrease Y
A method of automatically separating silicon wafers on a masking sheet by pressing forward and rotating the axis break roller, then pressing and rotating the X-axis break roller, which moves perpendicularly to the Y-axis break roller, in the same way as the Y-axis break roller. 2 Place the silicon wafer on the masking sheet so that the orienteering flat part of the silicon wafer is positioned perpendicularly or parallel to the rotational forward direction of the Y-axis break roller, place a slice protection sheet on the top surface of the silicon wafer, and Place the break roller receiving plate from the top of the slice protection sheet,
The pressing force from the Y-axis break roller on the back surface of the silicon wafer is automatically controlled using a memory device and made proportional to its contact area so that the pressing force on the remaining plate thickness portion after each groove cutting of the silicon wafer is constant. Increase or decrease Y
The axial break roller is pressed forward and rotated, and then the X-axis break roller, which moves perpendicularly to the Y-axis Bouley roller, is pressed and rotated forward in the same way as the Y-axis break roller, and then the chips separated in the above manner are placed. While pressing the placed sheet from above with a cylindrical sheet stopper, a circular wafer holder with a smaller diameter than the sheet stopper is pushed up from the bottom of the masking sheet to uniformly spread the masking sheet on the top of the wafer holder outward from the center. In this expanded state, the O-ring fitted from the upper outer periphery of the wafer holder to the lower part of the ring stopper with the same diameter is brought into contact with a ring pusher with an inner diameter slightly smaller than the outer diameter of the O-ring, and rolled down. A method of automatically separating silicon wafers on a masking sheet by fitting and fixing them into an O-ring groove.