JPH04297056A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To easily make a pellet to be thin in thickness and suppress the generation of cracking and chipping of wafer so as to reduce the wear of dicing blade by performing dicing for a semiconductor wafer surface by shorter cutting depth than its overall thickness and then grinding the rear face of the semiconductor wafer. CONSTITUTION:A semiconductor wafer 1 is half-cut along with scribe lines by using a dicing blade 3. The depth of the half-cut grooves 4, 4... is made to be almost same as the thickness of a pellet of semiconductor device which is subjected to manufacture. A surface protecting tape 5 is stuck on the surface 1a of the semiconductor wafer 1 in order that the surface of the semiconductor 1 is protected when grinding the rear face. Then, the rear face 1b of the semiconductor 1 is etched to obtain the specified pellet thickness for the wafer 1, and the wafer 1 is pelletized. After such processing, the semiconductor wafer 1 is wet-etched to remove the deformation due to rear face grinding. Thus, the wear of dicing blade can be reduced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a semiconductor device, in which backside grinding and dicing are performed after pad windows are formed in a passivation film.

0002

[Prior Art] The so-called semiconductor wafer post-processing is performed after pad windows are opened in the passivation film of a semiconductor wafer.
Conventionally, this was done as follows. That is, a resist film for surface protection is applied to the surface of a semiconductor wafer, a hard tape is attached to the surface of the resist film, the back side is ground in this state to make the thickness of the semiconductor wafer a predetermined value, and then the back side is ground. The back surface of the semiconductor wafer was etched to remove the grinding strain generated on the back surface of the semiconductor wafer and to reduce the warpage of the wafer, and then a semiconductor device function test [2PC (
A second pellet check) is carried out, and defective pellets are marked with dots using ink, and the ink is further burned into the wafer.Then, the back side of the semiconductor wafer is pasted onto a dicing tape and diced to pelletize the wafer.

0003

However, the above-mentioned conventional semiconductor wafer post-processing is becoming unable to meet the demand for thinner packages. This is because there is a demand to reduce the thickness of the package to, for example, 1 mm or less, but in order to meet this requirement, the thickness of the semiconductor pellet must be reduced to 250 to 200 μm or less. It is extremely difficult to make the film as thin as possible, and was nearly impossible in the past. Further, even if it were possible to make the semiconductor wafer thinner, chips and cracks are likely to occur in the semiconductor wafer between back grinding and dicing, and the incidence of chipping and cracking in semiconductors is particularly high.

[0004] Semiconductor device function test (2P
In C), the function of the circuit is electrically checked by applying the probe to the electrode pad of the semiconductor wafer, but in order to perform an accurate check, a certain level of pressure from the probe against the semiconductor wafer, that is, stylus pressure is required. becomes. Therefore, if the semiconductor wafer is thin, it is more likely to crack and chip due to the stylus pressure.

Furthermore, conventional dicing was full-cut dicing, that is, dicing in which the back side of the semiconductor wafer was adhered to a die bond tape and the semiconductor wafer was cut from the front side with a cutting depth deeper than the thickness of the semiconductor wafer. The dicing blade was severely worn. Figure 3
is a diagram showing the relationship between the depth of cut of the blade and the amount of blade wear (per 5000 cut lines). From this figure, if you cut so that silicon remains uncut (half cut), the amount of wear will be as small as 10 μm, but if you cut into the tape, It can be seen that if the tape is cut (full cut), the wear will be extremely large in proportion to the amount of tape cut. In addition, there was also the problem that the aluminum pads and wiring films on the surface of the semiconductor wafer were contaminated by ink marking dots attached to defective pellets during semiconductor processing and silicon dust generated during dicing, resulting in wire bond defects, short circuit defects, etc.

The present invention has been made to solve these problems, and the thickness of the semiconductor device (pellet thickness)
Easily thins the wafer, reduces the incidence of wafer cracking and chipping, reduces wear on the dicing blade, and eliminates contamination on the semiconductor wafer surface caused by ink marking dots created during semiconductor device function tests and dust generated by dicing. Furthermore, it is an object of the present invention to completely eliminate distortion caused by back grinding and dicing.

[0007]

[Means for Solving the Problem] A method for manufacturing a semiconductor device according to claim 1 is characterized in that dicing is performed from the surface of a semiconductor wafer at a cutting depth shallower than the thickness of the semiconductor wafer, and then the back surface of the semiconductor wafer is ground. do. A method for manufacturing a semiconductor device according to a second aspect of the invention is characterized in that the cutting depth of the dicing is made approximately equal to the pellet thickness. A third aspect of the method for manufacturing a semiconductor device is characterized in that backside grinding is performed with a surface protection tape attached to the front surface of the semiconductor wafer. A method for manufacturing a semiconductor device according to a fourth aspect of the present invention is characterized in that after the back surface of the semiconductor wafer is ground, strain removal etching is performed on the back surface of the semiconductor wafer.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a semiconductor device according to the present invention will be explained in detail below according to the illustrated embodiments. FIGS. 1A to 1F are cross-sectional views showing one embodiment of the method for manufacturing a semiconductor device of the present invention in the order of steps. (A) A semiconductor device function test is performed on the semiconductor wafer in which pad windows have been opened for the passivation film by applying the probe 2 to the electrode pad as shown in FIG. 1(A). Then, defective pellets are marked with ink dots. After marking, the dot-marked ink is printed.

(B) Next, as shown in FIG. 1 (B),
A scribe line of a semiconductor wafer 1 is half-cut by a dicing blade 3. 4, 4, . . . are grooves formed by half-cutting. The depth of the grooves 4, 4, . . . is preferably approximately equal to the pellet thickness of the semiconductor device to be manufactured. For example, if the pellet thickness is desired to be 200 μm, the depth of cut is set to 200 μm. It is clear from FIG. 2 that since the half-cut is performed in this way, the wear of the dicing blade is reduced.

(C) Next, as shown in FIG. 1 (C),
For example, a UV radiation-curable tape 5 is attached to the surface 1a of the semiconductor wafer 1 as a surface protection tape. This surface protection tape is used to protect the surface of the semiconductor wafer 1 during backside grinding of the semiconductor wafer 1 which will be performed later. Incidentally, as shown by the two-dot chain line, the surface protection tape 5 may be tensioned using the ring boulder 6, and the surface protection tape 5 may be attached to the surface 1a of the semiconductor wafer 1 in this state. (D) Next, as shown in FIG. 1(D), the back surface 1a of the semiconductor wafer 1 is etched to form the wafer 1 to a predetermined pellet thickness (which is also the depth of the half-cut for dicing). For example, 200 μm) and pelletize. 1c, 1c, . . . are semiconductor pellets.

After that, wet etching may be performed on the semiconductor wafer 1 to remove distortion caused by back grinding. Then, it is not only possible to simply remove the strain caused by back grinding, but also the strain generated on the side surfaces of the semiconductor pellets 1a, 1a, . . . by dicing [step (B)]. Although this etching step for removing strain caused by back grinding is not an essential step, if this etching step is provided, it will eliminate not only the strain caused by back grinding but also the strain generated on the side surfaces of the semiconductor pellets 1a, 1a, . . . due to dicing. It also has the effect that it can also be removed.

(E) Next, as shown in FIG. 1 (E),
A die bonding tape 7 is attached to the back surface 1b of the semiconductor wafer 1 that has been pelletized. In this case, the tape 7 used has a stronger adhesive force than the surface protection tape 5. Otherwise, the surface protection tape 5 will not be able to be peeled off.
This is because the tape 7 would peel off from the semiconductor wafer 1. However, as surface protection tape 5, U
When a V-irradiation-curable tape is used, the die-bonding tape 7 may be the UV-irradiation-curable tape or one with a weaker adhesive strength. This is because the adhesive strength of UV irradiation-curable tapes decreases to several tenths of a tenth when exposed to UV irradiation. That is, before peeling off the surface protection tape 5,
If V irradiation is used, it can be used as a die bonding tape even if the adhesive strength is stronger than the adhesive strength of the UV irradiation curable tape after UV irradiation, even if it is weaker than the adhesive strength of the UV irradiation curable tape before UV irradiation. It is.

(F) Thereafter, as shown in FIG. 1(F), the surface protection tape 5 is peeled off. In addition, surface protection tape 5
In the case of a UV irradiation-curable tape, it is preferable to lower the adhesive strength by UV irradiation and then peel it off. Further, when the surface protection tape 5 is a water-soluble adhesive tape, cleaning with pure water is performed as a post-treatment after peeling, and the tape is used for die bonding.

According to the present method for manufacturing a semiconductor device, the thickness of the semiconductor device (pellet thickness) can be reduced by reducing the depth of cut during half-cut dicing, and it is possible to reduce the thickness of the semiconductor device to approximately 200 μm. About, 5
It is also easy to make it 0 μm. And the dicing can be done without wafer holding tape. Also,
Although the pellet thickness can be reduced, this is done at the backside grinding stage after dicing, and the semiconductor wafer is thick at the semiconductor and dicing stage. Therefore, cracks and chips are less likely to occur in the semiconductor wafer and in the process from dicing to dicing, especially in the handling process, and the yield is improved.

[0015] Furthermore, since the cut for dicing is a half cut rather than a full cut, wear of the dicing blade can be reduced. Further, ink marking dots and silicon dust caused by semiconductor or back grinding can be removed together with the surface protection tape 5 when the surface protection tape 5 is peeled off. Therefore, it is possible to prevent wire bonding defects, short circuit defects between wirings, and moisture resistance defects due to such contamination. By etching the backside of the semiconductor wafer 1 after backgrinding, it is possible to remove not only backside grinding strain but also dicing strain generated on the side surface of the pellet due to dicing, thereby further improving characteristics and reliability. In addition, since a resist film is not used as a surface protection means, there is no need to use expensive indirect materials (resist, resist removal liquid).
Further, there is no need to perform troublesome resist coating or resist cleaning. Therefore, the material cost is low and the number of man-hours is small.

[0016]

The method for manufacturing a semiconductor device according to claim 1 is characterized in that dicing is performed from the surface of a semiconductor wafer to a cutting depth shallower than the thickness of the semiconductor wafer, and then the back surface of the semiconductor wafer is ground. . Therefore, according to the method for manufacturing a semiconductor device according to the first aspect, since dicing is performed by half-cutting, wear of the dicing blade can be reduced. Since the back surface grinding is performed at the final stage of the wafer post-processing process, a process that is likely to cause cracking or chipping of the semiconductor wafer is performed when the semiconductor wafer is thick. Therefore, the semiconductor wafer is less likely to be cracked or chipped. A second aspect of the method for manufacturing a semiconductor device is characterized in that the cutting depth of the dicing is approximately equal to the pellet thickness of the semiconductor device to be obtained. Therefore, according to the method for manufacturing a semiconductor device according to the second aspect, by back-grinding the semiconductor wafer to the point where the semiconductor wafer is diced, the thickness of the pellet of the semiconductor device can be made the same as the thickness of the dicing cut. Therefore, by reducing the cutting depth of dicing, the pellet thickness can be arbitrarily reduced, and an extremely thin pellet thickness of 100 μm or less can be achieved. A method of manufacturing a semiconductor device according to a third aspect of the present invention is characterized in that backside grinding is performed with a surface protection tape attached to the front surface of the semiconductor wafer. Therefore, according to the method for manufacturing a semiconductor device according to the third aspect, by peeling off the surface protection tape, it is possible to remove contamination caused by ink marking dots and dies that are attached or generated during a semiconductor device function test or dicing. Therefore, it is possible to prevent wire bonding defects, inter-wiring short circuit defects, and moisture resistance defects due to contamination. Since a resist film is not used as a surface protection means, there is no need to use expensive indirect materials (resist, resist removal liquid), and there is no need to perform troublesome resist coating or resist cleaning. Therefore, the material cost is low and the number of man-hours is small. Therefore, it is possible to reduce the cost of the semiconductor device. A method of manufacturing a semiconductor device according to a fourth aspect of the present invention is characterized in that after the back surface of the semiconductor wafer is ground, strain removal etching is performed on the back surface of the semiconductor wafer. Therefore, according to the method for manufacturing a semiconductor device according to claim 4, after dicing by half-cutting and pelletizing by back grinding, the back surface of the semiconductor wafer is etched to remove strain. It is also possible to remove dicing distortion that occurs on the side surfaces, and it is possible to improve characteristics, quality, and reliability.

[Brief explanation of drawings]

1A to 1F are cross-sectional views showing one embodiment of a method for manufacturing a semiconductor device of the present invention in the order of steps;

FIG. 2 is a diagram showing the relationship between the dicing depth of cut and the wear of the dicing blade, explaining one of the problems that the invention aims to solve.

[Explanation of symbols]

1 Semiconductor wafer 1a Surface 1b Back side 1c Semiconductor pellet 4 Dicing groove 5　Surface protection tape 7　Diebond tape

Claims (4)

[Claims] 1. A method for manufacturing a semiconductor device, comprising dicing the semiconductor wafer from its surface to a cutting depth shallower than its thickness, and then grinding the back surface of the semiconductor wafer. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the depth of the cut in the dicing is made approximately equal to the pellet thickness of the semiconductor device to be manufactured. 3. The method of manufacturing a semiconductor device according to claim 1, wherein the back surface grinding is performed with a surface protection tape adhered to the surface of the semiconductor wafer. 4. Claims 1 and 2, characterized in that after back grinding, strain removal etching is performed on the back surface of the semiconductor wafer.
Or the method for manufacturing a semiconductor device according to 3.