JP3154194B2 - Method for manufacturing semiconductor device chip - Google Patents

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 chip having a dicing step of a wafer on which a semiconductor device or the like is formed, and more particularly to a method for effectively preventing cutting chips generated during dicing from sticking to a device surface. To improve the yield after device assembly.

[0002]

2. Description of the Related Art For example, in a semiconductor process, a plurality of identical devices are formed on a wafer at one time. The technique of separating these devices from each other to form individual chips prior to assembly is called dicing. This dicing is generally performed by forming a cutting groove in a device non-forming region on a wafer using a dicing blade having a diamond needle or the like embedded at the tip. For example, as shown in FIG. 2, in a wafer 10 in which a plurality of rectangular devices 12 are regularly and horizontally formed on a substrate 11, cutting grooves 16 are formed between each row and each column of the devices 12. It is. In particular, the cutting groove 16 is formed halfway in the thickness direction of the substrate 11, scribing (scribing) when the final division of the chip is performed by mechanical breakage, and cutting is performed over the entire thickness direction of the substrate 11, The case where the chips are divided at the same time is called blade sawing.

By the way, dicing is generally performed on the wafer 10.
This is performed while flowing pure water over the surface of the substrate. This aims at removing frictional heat generated during cutting, imparting lubricity, removing cutting chips, and the like. FIG. 3A schematically shows a state in which a cutting groove 16 is formed between the devices 12 formed on the substrate 11 by using a dicing blade 13. The pure water 15 is supplied to the dicing blade 13
Is supplied from the direction of the arrow a to the nozzle 14 opened near the nozzle 14 and flows down from the tip of the nozzle 14. Due to the flow of the pure water 15, the cuttings 17 generated by the dicing of the wafer 10 flow away in the direction of the arrow b.

[0004]

However, a part of the surface of the wafer 10 may be temporarily dried during dicing. For example, as shown in FIGS. 2 and 3A, a region covered with pure water 15 and a dry region 10a are generated. If the cuttings 17 adhere to the device 12 existing in the drying area 10a, if the drying time is increased to some extent, the cuttings 17 adhere to the surface of the device 12, and the pure substance is again deposited on the drying area 10a. Even if the water 15 flows, it often happens that it cannot be easily removed.

[0005] The cutting chips 17 remain on the device 12 even after the dicing is completed, as shown in FIG.

The cutting chips 17 are mainly derived from the substrate 11. For example, when the substrate 11 is a silicon substrate, silicon is a main component of the cutting chips 17. When the device 12 is sealed with a packaging material via wire bonding or the like with the cutting chips 17 remaining, the cutting chips 17 press the surface of the device 12. In particular, when cutting chips 17 having high hardness, such as silicon, press against a material layer having low hardness, such as an Al wiring layer, defects such as disconnection and short-circuiting occur, which causes a deterioration in long-term reliability of the device 12. .

When the device 12 is, for example, a CCD solid-state image sensor, if the cutting dust 17 adheres to a portion corresponding to the light receiving surface, an image defect is caused, and the yield of the CCD solid-state image sensor is remarkably reduced.

In order to prevent such cutting chips 17 from sticking, hardware such as increasing the flow rate of pure water, optimizing the opening position of the nozzle, and adjusting the number of revolutions of the dicing blade, etc. The surface has been devised, but all have poor reproducibility and little effect. Accordingly, an object of the present invention is to provide a method of manufacturing a semiconductor device chip capable of improving the yield after assembling a device by preventing cutting chips from sticking to the device surface.

[0009]

SUMMARY OF THE INVENTION A method of manufacturing a semiconductor device chip according to the present invention is proposed to achieve the above-mentioned object. The method includes flowing pure water over a surface of a wafer on which devices are formed. The method includes a wafer dicing step of forming a cutting groove in a device non-formation region of the wafer, and the wafer is subjected to a hydrophilic treatment before forming the cutting groove.

The present invention is also characterized in that a plasma treatment is performed as the hydrophilic treatment.

The present invention is further characterized in that the device is a CCD solid-state imaging device.

[0012]

According to the present invention, since the wafer is subjected to a hydrophilic treatment before dicing, pure water flows while spreading uniformly on the wafer surface, and does not form a local dry area. In addition, since the pure water is always flowing, the cutting chips generated in the vicinity of the dicing blade are immediately carried away by the water flow and do not adhere to the device. Therefore, cutting chips can be effectively removed from the surface of the wafer. As a result, foreign matter does not exist between the device and the packaging material, and the yield of the device after assembly can be improved.

As the hydrophilic treatment, a plasma treatment is effective. Since passivation is performed at the final stage of a normal device process, the surface of the wafer is covered with a passivation film made of silicon nitride, polyimide, or the like immediately before the wafer enters the dicing step. Therefore, the above-described plasma treatment may be considered mainly as surface modification of the passivation film.

Although the details of the chemical change on the wafer surface caused by the plasma treatment are not always clear,
This is considered to be the formation of a dangling bond by the incident energy of ions in the plasma, the introduction of a hydrophilic group and / or a polar group by the bonding of another atom in the plasma to the dangling bond.

The present invention has the effect of improving the reliability and yield for all kinds of devices.
This is effective for a CD solid-state imaging device. This is because this element has a light receiving portion on the upper surface of the device and is naturally susceptible to the adverse effects of foreign matter on the wafer surface.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described. In this embodiment, prior to dicing a wafer having a CCD solid-state imaging device formed on a silicon substrate,
This is an example in which a wafer surface is subjected to a hydrophilic treatment by O ₂ plasma treatment. This process will be described with reference to FIG.

First, as shown in FIG. 1A, a wafer W having a CCD solid-state imaging device 2 formed on a silicon substrate 1 is set in a plasma processing apparatus, and O ₂ is placed in the apparatus.
Gas was introduced. As an example, a gas pressure of 133 Pa (1 To
rr), an RF power of 100 W (13.56 MHz), and a processing time of 10 seconds were subjected to O ₂ plasma processing to hydrophilize the surface of the wafer W. When O ₂ plasma is used in this way, it is necessary to use an O ₂ plasma ashing apparatus for removing a resist mask in a normal device process under conditions that are relaxed to the extent that a rapid combustion reaction does not occur. It is simple.

The effect of the hydrophilic treatment lasted for several months or more. If the effect is reduced during the waiting time from the hydrophilic treatment to the dicing, the hydrophilicity can be restored by performing the same treatment again. In addition, this hydrophilic treatment does not adversely affect the performance and shape of the device.

Next, the wafer W subjected to the hydrophilic treatment was diced. The dicing method is the same as the conventional one.
That is, as shown in FIG. 1B, the pure water 5 is supplied to the nozzle 4 opened in the vicinity of the dicing blade 3 from the direction of the arrow A, and flows down from the tip of the nozzle 4.
From the vicinity of the cutting groove 6 formed along the trajectory of the dicing blade 3, cutting chips 7 containing silicon as a main component are generated, and the cutting chips 7 ride on the flow of the pure water 5 and surround the periphery of the wafer W. Transported in the direction indicated by the arrow B, and flows away in the direction indicated by the arrow B. At this time, the layer of pure water spreads uniformly on the surface of the wafer W due to its high hydrophilicity, and no dry area is generated. Therefore, the cutting chips 7 did not remain on the wafer W.

After the dicing in the XY directions has been completed, pure water is kept flowing for a while, and then the wafer W is dried. As shown in FIG. Could be obtained. Thereafter, the wafer W is divided along the cutting groove 6 by applying a mechanical stress, and chips of the individual CCD solid-state imaging devices 2 are formed. Then, packaging is performed according to a normal process. In addition, the occurrence rate of image defects was significantly reduced as compared with the conventional case.

The present invention is not limited to the above-described embodiment. For example, devices formed on a wafer include various types of ICs, memories, and compound semiconductor devices in addition to the CCD solid-state imaging device described above. There may be. Also,
The gas used for the plasma treatment is not limited to O ₂ gas, and H ₂ , N _2, etc. may be appropriately selected and used according to the constituent material of the device surface.

[0022]

As is clear from the above description, by applying the present invention, it is possible to effectively prevent cutting chips generated during dicing from sticking to the device surface, and to prevent the device from being assembled. Reliability and yield can be significantly improved. Moreover, the present invention does not require any hardware change or adjustment of the conventional dicing apparatus,
The reproducibility and the safety are high, and there is no possibility that the throughput and the economic efficiency are deteriorated.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating an example of a process to which the present invention is applied in the order of the steps. FIG. 1A is a diagram illustrating an O ₂ plasma process performed on a wafer having a CCD solid-state imaging device formed on a silicon substrate. (B) represents a step of forming a cutting groove while flowing pure water, and (c) represents a step of drying the wafer after dicing.

FIG. 2 is a schematic plan view showing a state in which pure water is not uniformly spread on the surface of a wafer and a dry region is generated in a conventional process example.

3A and 3B are schematic cross-sectional views for explaining a problem of a conventional process example, where FIG. 3A is a state in which pure water does not spread evenly during dicing and a dry area is generated, and FIG. The state in which the cutting chips are fixed on the top is shown respectively.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Silicon substrate 2 ... CCD solid-state imaging device 3 ... Dicing blade 4 ... Nozzle 5 ... Pure water 6 ... Cutting groove 7 ... Cutting waste W ... Wafer

Continuation of the front page (72) Inventor Naoki Sawada 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (56) References JP-A-60-16442 (JP, A) JP-A-54-101271 (JP, a) JP Akira 57-159039 (JP, a) JP Akira 63-133534 (JP, a) JP flat 4-139856 (JP, a) (58 ) investigated the field (Int.Cl. ⁷ , DB name) H01L 21/301 B28D 7/02 H01L 27/14

Claims (3)

(57) [Claims] 1. A wafer dicing step of forming a cutting groove in a device non-forming region of a wafer while flowing pure water on a surface of the wafer on which the device is formed, and prior to forming the cutting groove, Manufacturing a semiconductor device chip, wherein the wafer is subjected to a hydrophilic treatment.
Method. 2. The semiconductor device chip according to claim 1, wherein the hydrophilic treatment is a plasma treatment .
Production method. 3. The method for manufacturing a semiconductor device chip according to claim 1, wherein said device is a CCD solid-state imaging device .