JPS6327580A - Adhesive tape - Google Patents

Abstract

PURPOSE:To obtain an adhesive tape for use in the production of semiconductor devices, etc., effective for division of wafers, by applying on the base surface an adhesive material prepared by mixing adhesive substances giving variable adhesivity by the irradiation of specified rays. CONSTITUTION:The objective light-transmittable adhesive tape can be obtained by applying, through the irradiation of specified rays (e.g. ultraviolet rays), on either or both of surfaces of a base material, an adhesive material prepared by mixing two or more kinds of adhesive substances with the adhesivity variable depending on, for example, wavelength or irradiation time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a technique that is effective for use in dividing wafers used in manufacturing semiconductor devices and the like.

[Conventional technology]

Regarding semiconductor wafer division technology, see, for example, "IC Mounting Technology" (edited by the Japan Microelectronics Association), published by Kogyo Kenkyukai Co., Ltd., January 15, 1980, Pl.
It is described in oo-Plot. This article introduces a technique in which a wafer is divided (diced) on a plastic adhesive tape and then the pellet portion is picked up from the back side of the tape using a push-up jig.

The present inventor studied the above-mentioned wafer dividing technique.

The following are the techniques studied by the present inventor, and the outline thereof is as follows.

That is, when dividing a wafer, it is known that dicing and pink amplification are performed while the wafer is attached to an adhesive tape that is attached with a predetermined tension to a frame member made of an aluminum alloy or the like.

By the way, when performing pick amplification, if the adhesive strength of the adhesive tape is too weak, the pellets may be misaligned or scatter during dicing.On the other hand, if the adhesive strength is too strong, pink-up may occur. During this process, the pellets may not easily separate from the adhesive tape, making it difficult for the collet to adsorb them.

For this reason, UV tape (Ult-ra) is used as an adhesive tape.
One possibility is to cover the wafer with a transparent plastic tape called Violet Tape, whose adhesive strength can be reduced by irradiation with ultraviolet light.

That is, a strong adhesive force is maintained during dicing, and just before pick-up, the back side of the UV tape is irradiated with ultraviolet rays to reduce the adhesive force and facilitate pink amplification of the pellets.

[Problem that the invention seeks to solve]

However, in the above technique, the degree of adhesive strength that decreases due to ultraviolet irradiation is predetermined, and the inventors have revealed that it is not possible to obtain an appropriate adhesive strength for each pellet specification. That is, the relationship between the adhesive strength of the UV tape and the ultraviolet irradiation time has a characteristic that the adhesive strength stabilizes at a predetermined low level after a predetermined period of time, for example, about 10 seconds, has elapsed after the start of ultraviolet irradiation. The adhesive strength after irradiation is set in advance for each adhesive tape. However, as mentioned above, the degree of adhesion obtained after UV irradiation differs depending on the pellet size, and it is desirable to obtain an appropriate adhesion force.In other words, for products with relatively small pellet sizes such as transistors, Even if the adhesive strength is maintained to a certain extent afterward, it does not interfere with the big amplifier, and on the contrary, it can prevent the pellets from scattering. On the other hand, in products with a relatively large pellet size, such as memory devices, if strong adhesive strength remains even after irradiation, pink amplification may become difficult.

Therefore, in order to obtain the optimal adhesive strength when picking up, it is necessary to prepare in advance UV tapes of multiple standards with different reaction adhesive strengths depending on the pellet size, which makes the work complicated when producing a wide variety of products in small quantities. The present inventor has clarified that this may occur.

The present invention has been made focusing on the above problems,
The purpose is to provide a technology that can realize highly reliable wafer division.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means for solving problems]

A brief overview of typical inventions disclosed in this application is as follows.

In other words, 2 exhibits different adhesion depending on irradiation with a predetermined light.
The adhesive tape is coated with an adhesive material mixed with the above-mentioned adhesive substances.

[Effect]

According to the above-mentioned means, the adhesive force can be changed by changing the method of irradiating the predetermined light, so that adhesive forces corresponding to a plurality of pellet sizes can be obtained with a single adhesive tape.

[Example 1] Fig. 1 is a plan view showing a state in which a UV tape according to an embodiment of the present invention is applied to a frame used for dividing semiconductor wafers, and Fig. 2 is a plan view showing this frame. ~
■A cross-sectional view along the line, Figure 3 is a conceptual diagram showing the adhesive material applied on the tape base, Figure 4 is an explanatory diagram showing the state of ultraviolet irradiation, and Figure 5 is an explanation showing the characteristics of adhesive strength and irradiation time. It is a diagram.

The frame 2 to which the UV tape 1 of Example 1 is adhered is used for dividing wafers in the manufacturing process of semiconductor devices, and the wafer 3 is adhered to the UV tape 1 and diced in this frame 2. It is now possible to do so.

The frame 2 has a ring-shaped frame member 2a made of stainless steel, on which a UV tape 1 is attached with a predetermined tension, and the adhesive side of the UV tape 1 is placed with the surface on which the element is formed facing upward. A wafer 3 is attached thereto.

The wafer 3 is made up of a large number of pellets 3a arranged vertically and horizontally, each unit being a pellet 3a having a memory capacity of, for example, 1 megabyte.

Further, the cross-sectional structure of the UV tape 1, as shown in FIG. 3, has a structure in which an adhesive material 5 is applied to one side of a tape base 4 made of transparent plastic. In Example 1, the adhesive material 5 applied to the tape base 4 is composed of three adhesive particle components A+, B+, and C7, and each of these adhesive particle components At, B
+ and CI have the property that their adhesive strength decreases in response to different values of ultraviolet wavelength.

In other words, the adhesive particles A1 have the property that their adhesive strength decreases in response to ultraviolet wavelength a, the adhesive particles B and C3 have the property that their adhesive strength decreases in response to ultraviolet wavelength C, respectively. have.

Next, a wafer vl process to which the above UV tape 1 is applied will be explained.

With the wafer 3 attached to the adhesive surface of the UV tape 1 attached to the frame member 2a, dicing of the wafer 3 is first performed. Here, the dicing in Example 1 is as follows:
For example, instead of so-called full dicing, in which the wafer 3 is completely separated from the front surface to the back surface, each pellet 3a is separated by leaving a thickness of, for example, about 20 μm near the back surface of the wafer 3.
This is so-called semi-dicing, in which the wafers are processed into connected blocks.

Moreover, although the above-mentioned dicing is performed along the boundaries of each pellet 3a, T E G (Testing Elem
In a wafer (not shown) on which a surplus region such as an entGroup section is formed, dicing is performed along the TBG section.

After the dicing is completed, the UV tape 1 of the frame 2 is irradiated with ultraviolet rays. This ultraviolet irradiation
As shown in Figure 4, for frame 2, UV tape 1
However, in the first embodiment, three types of ultraviolet irradiation lamps 6a with different ultraviolet irradiation wavelengths are used.
This is done by irradiating for a predetermined time using 6b and 6C.

That is, the ultraviolet irradiation lamp 6a emits ultraviolet wavelength a, the ultraviolet irradiation lamp 6b irradiates ultraviolet wavelength C, and the ultraviolet irradiation lamp 6c irradiates ultraviolet wavelength C.

Here, in the present Example 1, it is possible to change the reaction adhesive force after irradiation by controlling the three types of ultraviolet irradiation lamps 6a, 6b, and 6c as described below.

That is, when irradiation is performed by lighting only the ultraviolet irradiation lamp 6a, the adhesive particle component A1 reacts to the ultraviolet wavelength a, and only the adhesive force of this A decreases. However, at this time, adhesive particle components B1 and C8 do not react with the irradiation with ultraviolet wavelength a, and these B1 and C8
The adhesive force of No. 3 is maintained as it is even after irradiation, and therefore, by only irradiation with the ultraviolet irradiation lamp 6a, the UV tape 1 will have a relatively strong adhesive force even after irradiation.

Moreover, when irradiation is performed by lighting two types of ultraviolet irradiation lamps 6a and 6b, the adhesive force of adhesive particle components AI and B1 that react to ultraviolet wavelengths a and b decreases. Therefore, the adhesive force of the UV tape 1 is in a state where the reaction adhesive force as a whole is lower than that in the case of irradiation with only the ultraviolet irradiation lamp 6a.

Furthermore, if all three types of ultraviolet irradiation lamps 5a, 5b, and 6C are turned on and ultraviolet rays are irradiated, all of the adhesive particle components A, B, and CI will react, so the UV irradiation after ultraviolet irradiation will The reactive adhesive force of Tape 1 is the lowest value.

Here, a more specific explanation of the degree of change in the adhesive force of the UV tape 1 of Example 1 due to irradiation with each of the ultraviolet irradiation lamps 6a, 6b, and 6C is as follows, for example.

Note that the width of stainless steel alloy (not shown) is assumed to be 2.
These are the numerical values when measured by the so-called peeling method, in which a 0 nm adhesive tape is attached and the adhesive tape is vertically moved 17.11 M while being suspended from a tension gauge.

Here, if the UV tape 1 has an adhesive strength of about 500 g/20 m2 before irradiation with ultraviolet rays, for example, after a predetermined period of time has elapsed by irradiation with only ultraviolet ray a from the ultraviolet irradiation lamp 6a, The adhesive force decreases to about 100 g/200 (line indicated by a in FIG. 5).

Next, when irradiating with ultraviolet vAa and b, 70 g
/20wm (in Figure 5, a + b)
line shown).

Furthermore, when irradiating with ultraviolet rays a, b, and c, it is possible to reduce the adhesive strength to about 3'' g/20 as (line indicated by a+b+c in FIG. 5).

Adhesive component particles A having different reaction wavelengths as described above.

By selectively irradiating ultraviolet rays of different wavelengths using the adhesive material 5 which is a mixture of , B1 and C5, one side is 11
It can accommodate pellet sizes ranging from about 1 to about 15 fins on a side, and it is possible to obtain the optimal adhesive strength according to each pellet size.

For example, for relatively small products such as transistors with a pellet size of about 1U, a strong adhesive state is maintained by irradiation with ultraviolet A only.
On the other hand, for relatively large pellets of up to about 15u on one side, such as memory devices, ultraviolet ia, b is used.

By irradiating C, the adhesive force can be kept as low as possible.

In this way, by controlling the adhesive force after ultraviolet irradiation in accordance with the pellet size, it is possible to ensure optimal adhesive force at the time of pickup, and it is possible to achieve highly reliable pink-up.

After the ultraviolet rays have been irradiated by the ultraviolet ray irradiation lamp 6 as described above, each pellet 3a is transferred to the next step by means of a pink-up means (not shown) or the like.

As described above, according to this embodiment, the following effects can be obtained.

(1) By coating multiple types of adhesive particle components with different reaction characteristics on the tape base 4, it is possible to change the reaction of each adhesive particle component depending on the method of UV irradiation. It becomes possible to change the reaction adhesive force afterward, and it is possible to ensure the optimum adhesive force corresponding to the pellet size.

(2) By mixing three types of adhesive particle components At, B+, and C+ with different zero-reaction ultraviolet wavelengths and applying the mixture onto the tape base 4, different ultraviolet wavelengths a and b can be obtained.

Since it is possible to adjust the degree of reactive adhesive force in accordance with the selective irradiation of C, it is possible to obtain the optimum adhesive force during pick amplification according to the pellet size.

(3) According to (2) above, scattering of the pellets 3a during pink-up can be prevented, and highly reliable wafer division can be realized.

[Example 2] Figure 6 is a conceptual diagram showing the adhesive material coated on the tape base of LIV tape which is another example of the present invention, and Figure 7 is a diagram showing the case where the UV tape of Example 2 is used. FIG. 2 is an explanatory diagram showing the characteristics of adhesive strength and irradiation time.

Similar to the UV tape 1 of Example 1, the UV tape 21 of Example 2 has an adhesive material 25 coated on a tape base 4 made of transparent plastic. different in nature.

That is, in this Example 2, the adhesive particle components are composed of A Time has different characteristics.

That is, for example, adhesive particles A2 have a property that they react immediately after the start of irradiation with ultraviolet rays and their adhesive strength decreases. In addition, adhesive particles called B2 have 10
It has the property of reacting in about seconds and reducing its adhesive strength.

Furthermore, the adhesive particles called C2 have the property of reacting and decreasing their adhesive force in about 20 seconds after being irradiated with ultraviolet rays.

Therefore, according to the UV tape 21 of Example 2, the characteristics of the ultraviolet irradiation time and adhesive force are as shown in FIG. This will be explained more specifically as follows. First, upon irradiation with ultraviolet rays, the adhesive particles A2 immediately react and stabilize at a predetermined adhesive strength Gs+. Further, when irradiation with ultraviolet rays is continued, the adhesive particles B1 start reacting about 10 seconds after the start of irradiation. Adhesion state Mst that is stable for a predetermined period of time in a state where the adhesive force of Bt is reduced
becomes. Therefore, in this state of B2, the adhesive strength of A and B has decreased, while the adhesive strength of C2 is maintained in a strong state. After this, when the ultraviolet rays are further irradiated, the reaction of the adhesive particles C2 starts about 20 seconds after the start of the irradiation. This C! As a result of this reaction, the adhesive strength becomes Bss, and a UV tape 21 with reduced adhesive strength is obtained.

As described above, according to the second embodiment, by adjusting the ultraviolet irradiation time, the reaction adhesion states St, S can be adjusted according to the pellet size. or S, can be selectively obtained.

Therefore, it is possible to obtain different reaction adhesive forces using a single wavelength UV irradiation lamp, so there is no need to change the UV irradiation equipment.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. For example, in the examples, only the case where three types of adhesive particle components having different reaction characteristics were mixed was explained, but it is also possible to mix two or four or more types of adhesive particle components.

In the above explanation, the invention made by the present inventor was mainly applied to its field of application, which is a so-called adhesive tape for attaching a wafer to a semiconductor device.
The present invention is not limited thereto, and can also be applied to adhesive tapes for attaching wafers used in the manufacture of other electronic components such as transistors or diodes.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

That is, it is a translucent adhesive tape having at least one surface coated with an adhesive material whose adhesive strength decreases when irradiated with a predetermined light, and the adhesive material has two or more adhesive tapes that exhibit different reactive tackiness depending on the irradiation with a predetermined light. By creating an adhesive tape structure with a mixture of adhesive substances, the adhesive force can be changed by changing the method of irradiation with a certain light, so a single adhesive tape can have adhesive strength that corresponds to multiple beret/ ) sizes. can be obtained selectively.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an adhesive tape according to an embodiment of the present invention applied to a frame of a semiconductor wafer; Fig. 2 is a cross-sectional view taken along the line ■-■ in Fig. 1 showing the frame; A conceptual diagram showing the adhesive material coated on the UV tape, Figure 4 is an explanatory diagram showing the state of ultraviolet irradiation, Figure 5 is an explanatory diagram showing the characteristics of adhesive strength and irradiation time, and Figure 6 is an explanatory diagram showing the characteristics of adhesive strength and irradiation time. Figure 7 is a conceptual diagram showing the adhesive material applied on the tape base of the UV tape of Example 2. Figure 7 is an explanatory diagram showing the characteristics of adhesive strength and irradiation time when the UV tape of Example 2 is used. be. DESCRIPTION OF SYMBOLS 1... UV tape, 2... Frame, 2a... Frame member, 3... Wafer, 4... Tape base,
5... Adhesive material, 6.6a, 6b. 6c...UV irradiation lamp, 21...UV tape,
25... Adhesive material, A+, B1. CI+Az,
Bt, Cz...adhesive particles 8, a, b, c-...ultraviolet light. Agent: Patent attorney Katsuo Ogawa.

Claims (1)

[Scope of Claims] 1. A translucent adhesive tape having at least one surface coated with an adhesive material whose adhesive strength decreases when irradiated with a predetermined light, the adhesive material having a reactive adhesive that changes depending on the irradiation with a predetermined light. 1. An adhesive tape characterized by being a mixture of two or more adhesive substances exhibiting properties. 2. The adhesive tape according to claim 1, wherein the adhesive strength of two or more adhesive substances decreases in response to different wavelengths of the predetermined light. 3. The adhesive tape according to claim 1, wherein the adhesive strength of each of the two or more adhesive substances decreases in response to different irradiation times of the predetermined light. 4. The adhesive tape according to claim 1, 2 or 3, wherein the predetermined light is ultraviolet light.