JPH0314049Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an ultraviolet irradiation device that irradiates ultraviolet rays to cure an ultraviolet curable adhesive.

2. Description of the Related Art In the process of manufacturing semiconductor devices, semiconductor pellets obtained by dividing a large number of semiconductor elements formed on a semiconductor wafer into individual element regions are used.

As shown in FIG. 5, this dividing operation involves attaching a semiconductor wafer 2 to a flexible sheet 1 made of vinyl chloride or the like on which an adhesive layer is formed, cutting the partitioned parts of the semiconductor elements using a dicing saw, etc. Split into semiconductor pellets. Next, this sheet 1 is attached to a ring-shaped frame (not shown), and the sheet 1 is stretched to widen the space between the semiconductor pellets and facilitate the removal of the semiconductor pellets. In this state, the semiconductor pellets are supplied to a mounting process, and individual pellets are taken out from the sheet and supplied to a substrate such as a lead frame. Vacuum suction collectors are generally used to remove these pellets, but if the pellets are too sticky, it will be difficult to peel them off from the sheet, reducing productivity, so various countermeasures have been taken. ing.

One method is to use an ultraviolet curing adhesive as an adhesive layer. Ultraviolet curing adhesive has strong adhesion when exposed to ultraviolet light, so pellets do not fall off from the workpiece when dividing pellets or attaching them to a ring-shaped frame.
After irradiation with ultraviolet rays, the adhesive hardens and its adhesive strength rapidly decreases, making it easy to remove the pellets.

Problems that the invention aims to solve: However, sheets using ultraviolet curable adhesives have uneven adhesive strength after curing, which can lead to failures in removing semiconductor pellets from the back of the sheet. An additional device was required to assist in pushing up and peeling off with a needle.

Means for Solving the Problems The present invention was proposed in view of the above-mentioned problems, and involves separating a number of workpieces from each other with a layer of ultraviolet curing adhesive on one side, and layering an adhesive layer between the workpieces. A cover is placed on the other side of the transparent member to cover the surface of the transparent member to which the work is attached, and which has a number of inert gas discharge ports facing the work. It is characterized by comprising an ultraviolet lamp for irradiating and curing.

Effect Even if the distance between the workpieces is small, the gas discharged from the inert gas outlet facing the workpieces will drive out the air between the workpieces and fill the workpieces with inert gas.
The interior surrounded by the cover is kept in a pressurized state, completely blocking outside air, and the adhesive can be cured well by ultraviolet irradiation.

Embodiment An embodiment of the present invention will be described below with reference to FIG.
In the figure, 3 is a transparent sheet (transparent member), and an ultraviolet curing adhesive 4 (for example, the product name UE-
10: Nitto Denko) layer is formed, and semiconductor pellets (work) 5 are pasted in an aligned state. The semiconductor pellets 5 are obtained by dividing a semiconductor wafer attached to a transparent sheet 3 into individual pellets by dicing or scribing, and then stretching the transparent sheet 3 in the radial direction to leave intervals so that they can be easily taken out. Reference numeral 6 indicates a ring-shaped frame that holds the peripheral edge of the transparent sheet 3. A housing 7 houses an ultraviolet lamp 8, and has an opening 7a on its top surface. 9 is a shutter placed between the ultraviolet lamp 8 and the opening 7a;
The ultraviolet irradiation time to the transparent member 3 arranged so as to cover is controlled. Reference numeral 10 denotes an inert gas N ₂ supply nozzle (inert gas discharge port) disposed above the opening 7a, facing the semiconductor pellet 5, and facing the cover 1.
2, and this cover 12 covers the surface to which the semiconductor pellet 5 is attached.

This operation will be explained below. First, the shutter 9 is closed and the transparent sheet 3 is placed over the opening 7a. Next, an inert gas such as nitrogen gas is blown from the nozzle 10 to expel the air between the semiconductor pellets, and the shutter 9 is opened to irradiate the ultraviolet curing adhesive 4 with ultraviolet rays for a certain period of time through the transparent sheet 3. .

The thickness of the semiconductor pellet 5 is, for example, 350μ to 500μ.
On the other hand, the dicing groove is several tens of micrometers wide, so the width of the dicing groove is narrow and deep valleys are formed, and even if inert gas is blown diagonally against the groove from the outside, a vortex is created at the opening of the valley. If the gas does not enter the groove sufficiently and the blown gas entrains outside air, the bottom of the groove, that is, the exposed portion of the adhesive layer, cannot be completely shielded from the outside air.

On the other hand, the nozzle 10 facing the pellet 5
The inert gas discharged from the inert gas is smoothly blown between the pellets 5, 5, completely expelling the air, and covering the exposed part of the adhesive 4. Moreover, since the part where the pellets are attached is covered with the cover 12, the inside of the cover 12 is covered. is in a pressurized state, there is no inflow of outside air, and the exposed portion of the adhesive 4 can be shielded from outside air during ultraviolet irradiation using a small amount of inert gas.

Then, the shutter 9 is closed, the supply of gas N ₂ from the nozzle 10 is stopped, and the transparent sheet 3 is taken out to complete the work.

FIG. 2 shows the residual adhesive strength of the adhesive obtained by the conventional method and the method using the apparatus according to the present invention. When the adhesive strength without UV irradiation is set as 100, in the conventional method, the adhesive strength is 50 to 30 in 1 second after UV irradiation, and even if it is irradiated for more than 10 seconds, it is around 20 and the adhesive strength is increased after irradiation for a longer time. The decrease was slight.

On the other hand, with the device of the present invention, after irradiation with ultraviolet rays,
The adhesive strength was 20 to 10 in seconds, converging to about 10 after 10 seconds of irradiation, and it was confirmed that the adhesive strength decreased significantly in a short period of time.

The present inventor discovered that the degree of decrease in adhesive strength of UV-curable adhesives is affected by whether or not the adhesive comes into contact with oxygen in the air during UV irradiation, and as shown in Figure 3. If the adhesive strength of the exposed portion 4a between the semiconductor pellets 5, 5 of the adhesive 4 does not decrease, the periphery of the adhesive surface of the pellet 5 will be held by the layer 4a with strong adhesive strength, and the lower surface 4 of the adhesive surface 4 will be held.
It was discovered that even if the adhesive force of b was sufficiently reduced, the adhesive force remained as a whole, which led to the creation of the device of the present invention.

FIG. 4 shows another embodiment of the invention. In the figure, the same reference numerals as in FIG. 1 indicate the same parts, and the explanation will be omitted.
The only difference from the apparatus shown in FIG. 1 is that a suction pad 11 is added to the nozzle 10. A plurality of suction pads are attached to the outer periphery of the nozzle, and a transparent sheet 3
The frame 6 holding the is adsorbed. The cover 12 is intended to minimize the diffusion of gas N ₂ blown out from the nozzle 10, and by setting a small distance between the lower end of the cover 12 and the transparent sheet 3, it is possible to completely block outside air from entering. .

Compared to the device shown in FIG. 1, this device also provides a
After placing the transparent sheet over the opening 7a, the ultraviolet rays can be irradiated immediately, reducing the working time.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be applied to any other member in addition to the semiconductor pellet. Also, transparent members
Any material that transmits ultraviolet rays, such as plastic or glass, can be used, and is not limited to sheet materials.

Effects As described above, according to the present invention, the ultraviolet irradiation time of the ultraviolet curable adhesive can be shortened, the residual adhesive strength can be reduced, and the variation thereof can be reduced, and the workpiece can be easily removed.

[Brief explanation of drawings]

Fig. 1 is a side sectional view showing an embodiment of the present invention;
The figure is a curing curve diagram of the adhesive, Figure 3 is a partially enlarged side sectional view of a transparent member to which a workpiece is adhered, Figure 4 is a side sectional view showing another embodiment of the present invention, and Figure 5 is a transparent sheet. FIG. 3 is a perspective view showing the attached semiconductor wafer. 3... Transparent member, 4... Ultraviolet curing adhesive,
5...Work, _N2 ...Inert gas, 8...Ultraviolet lamp.

Claims (1)

[Scope of utility model registration request] A large number of workpieces are separated from each other through a layer of ultraviolet curable adhesive on one surface, and the adhesive layer is exposed between the workpieces. An ultraviolet irradiation device comprising: a cover having an inert gas discharge port; and an ultraviolet lamp disposed on the other side of the transparent member for irradiating ultraviolet rays onto an adhesive layer and curing the adhesive layer.