JPS6054813A - Dicing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an example of a dicing method for dividing a semiconductor substrate on which a circuit is formed.

2. Description of the Related Art Structures and Problems Therein, various contact type image sensors have been developed for use in office equipment and computer input terminals.

The contact image sensor f requires a long line sensor of the same size as the original in order to read at the same magnification. Among them, the process technology has been established, and silicon I, C, which has excellent reliability.In the past, there was a movement to agglomerate contact-type image sensors by piecing together multiple chips and making them longer. be. However, in this case, errors in the joining of I, C, and chips limit the reading accuracy of the contact image sensor, so in order to realize a high-precision contact image sensor, Time)
condition is very important. However, as the resolution becomes higher, the distance between the sensors becomes narrower, so cutting must be done in a way that does not interfere with the semiconductor circuit due to micro-cranks during dicing.

Conventionally, when dividing a substrate into chips, a dicing saw was used to cut it leaving several tens to hundreds of microns.
Force is applied to the substrate in some way to divide it into chips, but the end faces of the uncut portions are not uniform due to the crystallinity of the substrate and the way the force is applied (Figure 1B). Therefore, when the chips obtained in this way are arranged in a straight line as a contact image sensor, the distance between the chips becomes irregular as shown in Fig. 2, and as a result, the sensors at both ends of the connection surface The spacing between the two images was uneven, making it impossible to obtain a high-resolution, high-precision contact image sensor.

Due to the influence of the micro-crack gun during dicing, I was not able to cut the chips near the scribe lane.

OBJECTS OF THE INVENTION An object of the present invention is to provide a dicing method that does not cause any trouble to the semiconductor circuits, such as microcranks, in the process of dividing a semiconductor substrate on which circuits are formed into chips using a dicing saw.

Structure of the Invention The dicing method of the present invention includes a first step of forming a groove on the very surface of a semiconductor substrate on which a circuit is formed, and a blade having a narrower blade thickness than the groove width obtained in the first step. This method has a second step of making a groove deeper than the groove depth of the first cutter 11 within the above groove width, and this allows dicing without causing any trouble to the semiconductor circuit such as micro cracks. This is effective for cutting substrates that have elements on them.

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

FIG. 3 is a diagram showing an embodiment of the present invention. Figure 3: People are
A cross-sectional view is shown after the dicing in the first step, and FIG. 3B is a cross-sectional view after the dicing in the second step.

In preparation, an adhesive sheet 32 is attached to a silicon substrate 31 on which a semiconductor circuit is formed. The adhesive sheet 32 is used to completely cut the silicon substrate 31 (in order to avoid damaging the stage of the dicing saw, and in this embodiment, the adhesive sheet 32 is made of elmwood made by Nit Denki Kogyo Co., Ltd.). I used a knob holder (product name).Set the above-prepared item on a dicing saw (manufactured by DISCO), and use a play j.
'J' fJ, the first step is to cut only the surface (10 to 30 microns) of the silicon substrate 31 on which the semiconductor circuit is formed using a 40 μm blade and make a groove 33 in the silicon substrate on which the semiconductor circuit is formed. Finish dicing. Next, replace the blade VCJJ'M with a blade thickness of 30 μm, set the blade so as to cut a part of the adhesive sheet 32, and perform the first dicing process! The wafer is aligned so that it is centered in the groove, and the second step of dicing is performed to completely cut the wafer. 34 pieces of dicing in the second process? It is i/J.

The IC chip thus obtained was removed from the contact sheet, and the IC chip circuit 4. ! ' (i1: m1
! I tried 4. As a result, since the dicing in the first step was performed only on the very surface, the chipping of the I'C chip was small (Figure 4), and the B1 chip on the circuit formed 10 μm away from the cut surface was small. Instead, an I, C, chip with the characteristics jf 1(' was obtained.

When cutting using the conventional dicing method, 1. C. There are large chips and many mechanical defects on the chip surface (Figure 4B). Furthermore, the characteristics of circuits formed 10 μm away from the cut surface may be unstable or may not exhibit any characteristics.

Next, when the LC and chips obtained in this example are arranged in a straight line, the end faces of the IJ and chip are fully capped during the second dicing, so a unified vertical surface cannot be obtained, and the chips The accuracy of the interval 1414 was very good (Fig. 5).

When r, c, and chips diced using the conventional dicing method are arranged in a straight line, the distance between the chips is b! , the variation of 4 is 5
8μm (blade thickness 26μm, uncut fit)
, when dicing at 100 μm) is the IjE obtained in this firearm example, and when the chips are arranged in a straight line, the variation in chip spacing is 8 μm or less, which is less than 10 μm.

Next, other embodiments will be described.

The semiconductor substrate on which the circuit has been formed is set on the stage of the guiding tool, and as shown in FIG.

The effects of the transistor 61 and resistor 62 formed in the test circuit are very different from each other.
z: jl: The first step of dicing was performed using a 40 μm thick blade with a distance α of 10 μm from the substrate surface.
Cuts and grooves were made at a depth of ~30 μm. Next, replace the blade with a blade thickness of 30 μm, and remove the semiconductor substrate by 1.
Center the blade so that it can be cut leaving 00μm,
The second step of dicing is performed after alignment is performed so that the groove obtained in the first step of dicing is centered. The semiconductor substrate obtained in this way is made into a chip by applying force, and
C. As a result of examining the circuit characteristics of the chip, there was no effect on the circuit and it showed normal characteristics.

By cutting the very surface of the substrate in the first step of dicing as described above, 1. Cj, it can be cut without damaging the characteristics of the chip. This is to cut without straining the epitaxial layer on the surface of the substrate on which the circuit is formed, and at least the cutting depth in the first step is the same as that in the second step. If the distortion cannot be applied, it is necessary to cut it to the end at least 10μ.
The cutting depth is m. Further, if the cutting depth exceeds 30 .mu.m, mechanical chips may suddenly occur, so the cutting depth in the first step is preferably 10 to 30 .mu.m.

In addition, in this example, the cutting depth in the first step was described as a case where the cutting was completed completely and a case where the cutting was performed with 11001i left, but the cutting depth in the second step was greater than the cutting depth in the first step. Any depth is fine, and the cutting depth can be changed depending on the purpose. Furthermore, regarding the blade thickness, it is clear that combinations other than those used in the examples may be used as long as the blade thickness used in the first step is thinner than the blade thickness used in the first step to perform the cutting in the second step. be.

As is clear from the explanation in Section 2 of ``Effects of the Invention'', the dicing method of the present invention includes a first step of forming a groove on the very surface of a semiconductor substrate on which a circuit is formed, and a width that is larger than the width of the groove obtained in the first step. This method uses a thin blade (thin blade) to cut a groove deeper than the groove depth in the first step within the groove width, and is said to cause microcracks, etc. that occur in the dicing method, which may impede the characteristics of the IC chip. This problem can be solved and it is effective for cutting substrates that have elements near the scribe plane.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a board cut by the conventional dicing method, Figure 1B is a cross-sectional view of the board in Figure 1 made into a chip,
Figure 2 is a cross-sectional view of chips made into chips using the conventional dicing method, Figure 3 is a cross-sectional view after the first step of dicing according to the present invention has been completed, and Figure 3B is a cross-sectional view after the second step of dicing has been completed. Figure 4 is a diagram showing the surface of the substrate after dicing according to the present invention; Figure 4B is a diagram showing the surface of the substrate cut by the conventional dicing method; Figure 5 is a diagram showing the surface of the substrate after dicing according to the present invention. FIG. 6 is a cross-sectional view of the chips cut by the dicing method, and is a diagram showing the surface condition of one die/two substrates cut by the dicing method according to the present invention. 11.31...semiconductor substrate, 12...r
, c chip, 32...adhesive sheet, 33...-
・・Groove cut by dicing in the first step, 34・−・・
・Groove cut in the second step of dicing, 61...
・Transistor, 62... Resistor, 63...
-Scribe lane, 64...Blade width for the first process, 66...Blade width for the second process. Name of agent Patent attorney Toshi Nakao 11 or 1 person Figure 1 Figure 2 Figure 4 (c) (B) Figure 5 Figure 6 Figure 3

Claims (2)

[Claims] (1) A first step of forming a groove on the very surface of a semiconductor substrate on which a circuit has been formed, and a first step of forming a first groove within the groove width using a blade having a thickness narrower than the width of the groove in the first step. A dicing method characterized by having a cutting edge that cuts deeper than the groove depth of the process. (2) The groove depth in the first step is 10 to 30μ from the surface of the substrate.
The dicing method according to claim 1, characterized in that the dicing method is made such that +JC.