TWI534914B - A bonding method for chips - Google Patents

Description

Wafer bonding method

The present invention relates to a method of bonding a wafer, and more particularly to a method of bonding a wafer having multi-stage UV light irradiation.

Among the medical detection technologies, biological cell detection technology is one of the most critical projects. In order to reduce the time spent on detection and improve the accuracy of detection, today's biological cell detection technology replaces the culture dish with a disposable biomedical wafer as a detection platform for new diseases and major diseases. However, in order to prevent the analyte from being externally affected in the flow path of the wafer, and to avoid the problem of leakage of the analyte, the biomedical wafer is sealed by two or more substrates to ensure Detect the accuracy of the data.

In the existing wafer bonding technology, the most commonly used thermocompression bonding method or UV adhesive bonding method is used to package the wafer. Among them, the process of thermocompression bonding tends to cause deformation of the substrate structure, and the process of thermocompression bonding takes a long time, which is disadvantageous for large-scale production and manufacture of the wafer. Compared with the method of hot-pressing and bonding the substrate, the process time of sealing the substrate by using the UV glue is short, and the substrate structure is not easily deformed. Therefore, the adhesion mode of the UV glue is advantageous for large-scale production of the medical wafer. In addition, in the literature on UV bonding technology, for example, "UV ADHESIVE BONDING TECHNIQUES IN ROOM TEMPERATURE FOR PLASTIC LAB-ON-A-CHIPS", which uses a squeegee to apply UV glue to the surface of the underlying substrate. After that, the upper substrate is bonded to the lower substrate coated with the UV glue, and finally the UV light curing UV glue is completed to complete the entire packaging process. However, there is no way to uniformly coat the UV glue using a squeegee to ensure uniform UV thickness. In addition, when the upper substrate is combined with the lower substrate, liquid UV glue may also penetrate into the flow channel.

Therefore, in the process of bonding the wafers, how to make the UV glue thin and flat, and to reduce the penetration of the UV glue into the flow channel, is worthy of consideration by those having ordinary knowledge in the field.

A method for bonding a wafer includes the following steps: First, a first substrate is provided, one of the first substrates being a first bonding surface. Next, a thin layer of photocurable adhesive is formed on the first bonding surface of the first substrate. Thereafter, the thin layer of the photohardenable adhesive is irradiated with a first luminaire to preliminarily cure the thin layer of the photohardenable adhesive. Then, a second substrate is provided, one of the second substrates is a second bonding surface, and the second bonding surface is bonded to the first bonding surface of the first substrate. Thereafter, the thin layer of the photohardenable adhesive is irradiated with a second luminaire to completely cure the thin layer of the photohardenable adhesive. Wherein, the wattage value of the second luminaire will be higher than the wattage value of the first luminaire. In the present invention, a photocurable adhesive refers to a colloid which, upon being irradiated with light in a certain wavelength range, generates a chemical reaction, thereby producing a solidification. The light emitted by the first luminaire and the second luminaire described above falls in a wavelength range in which the photohardening adhesive can be cured. The photohardening adhesive is, for example, a UV glue, and the thin layer of the photocurable adhesive is, for example, a thin layer of UV glue, and the first lamp and the second lamp are, for example, UV lamps.

In the above method of bonding a wafer, in step b, the photohardenable adhesive thin layer is formed on the first bonding surface of the first substrate by spin coating.

In the above method for bonding a wafer, the step d further includes the step of uniformly applying pressure to the bonded first substrate and the second substrate.

In the above method for bonding a wafer, wherein the second bonding surface of the second substrate has a plurality of microstructures, and when the second substrate is bonded to the first substrate, the microstructure can maintain the second substrate and the first substrate a certain distance.

In the above method of bonding a wafer, at least one flow path is provided on the second bonding surface of the second substrate.

In the above method for bonding a wafer, the method of spin coating is performed in a first stage and a second stage, the first stage is to rotate the first substrate using the first rotation speed value, and the second stage is to use The second rotational speed value rotates the first substrate, and the second rotational speed value is higher than the first rotational speed value.

In the above method of bonding a wafer, the wattage of the first luminaire is 36 watts, and the wattage of the second luminaire is 400 watts.

The above description of the present invention and the following description of the embodiments of the present invention are intended to illustrate and explain the principles of the invention.

10‧‧‧ wafer

101‧‧‧First substrate

101A‧‧‧ first fit surface

102‧‧‧second substrate

102A‧‧‧Second mating surface

1021‧‧‧ runner

1022‧‧‧Microstructure

103‧‧‧Light hardening adhesive

103'‧‧‧Light hardening adhesive thin layer

12‧‧‧Rot coating machine

121‧‧‧vacuum suction cup

20‧‧‧First lamps

30‧‧‧second luminaire

1 to 7 illustrate a bonding method of the wafer 10 of the present embodiment.

Please refer to FIG. 1 to FIG. 7 . FIG. 1 to FIG. 7 illustrate the combination of the wafer 10 of the embodiment. method. First, as shown in FIG. 1, a first substrate 101 is provided, and the first substrate 101 is disposed on a vacuum chuck 121 of a spin coater 12, and the first substrate 101 is not adsorbed by the vacuum chuck 121. That side is a first bonding surface 101A. Thereafter, an appropriate amount of photocuring adhesive 103 (for example, UV glue, viscous coefficient of 3200 cps) is poured into the center of the first bonding surface 101A of the first substrate 101. In the present embodiment, the light hardening is poured. The amount of the subsequent agent 103 was 1 mL. In the above, the material of the first substrate 101 is, for example, ceramic, plastic, enamel resin, rubber or metal. Further, the amount of the photo-curing adhesive 103 may be increased or decreased depending on the size of the first bonding surface 101A.

Next, as shown in FIG. 2, the spin coater 12 starts to spin-coat the first bonding surface 101A of the first substrate 101 to the first-stage photo-curing adhesive 103, and uses a first stage in the first stage. The first substrate 101 is rotated by a rotational speed value. In the present embodiment, the first rotational speed value is 200 rpm, and the operation is continued for 25 seconds. At this time, it can be seen that the photo-curing adhesive 103 gradually spreads over the first bonding surface 101A. Thereafter, as shown in FIG. 3, after the first stage of the photo-curing adhesive 103 is spin-coated, the spin coater 12 immediately enters the second-stage photo-curing adhesive 103 to be spin-coated, and in the second stage, The first substrate 101 is rotated using a second rotational speed value, and the second rotational speed value is greater than the first rotational speed value. In the present embodiment, the second rotational speed value is 1000 rpm, and the operation is continued for 12 seconds. After the first bonding surface 101A is spin-coated by the first and second stages of the photo-curing adhesive 103, a uniform liquid photo-curing adhesive thin layer 103' is formed on the first bonding surface 101A (for example, A thin layer of UV glue with a thickness of about 55um). Compared with the literature "UV ADHESIVE BONDING TECHNIQUES IN ROOM TEMPERATURE FOR PLASTIC LAB-ON-A-CHIPS" is a method of coating a UV glue using a squeegee, the wafer of this embodiment The combination of 10 uses a two-stage spin coating to further achieve a thin and flat effect of the photohardenable adhesive 103. In the present embodiment, the photocurable adhesive thin layer 103' is formed by two-stage spin coating, but those skilled in the art can also complete the photocurable adhesive thin layer 103 by only one-stage spin coating. 'Making, or otherwise forming a thin layer 103' of photohardenable adhesive.

Then, as shown in FIG. 4, the photo-curing adhesive thin layer 103' is irradiated with a first luminaire 20, which in this embodiment is, for example, a 36W UV lamp, which is irradiated with a light-hardening adhesive. The time of layer 103' is 8 to 10 seconds. The light emitted by the first luminaire 20 causes the photohardenable adhesive layer 103' to be initially cured to reduce the fluidity of the photohardenable adhesive layer 103'. Then, as shown in FIG. 5, a second substrate 102 is provided. One of the second substrate 102 is a second bonding surface 102A, and a plurality of grooves are formed on the second bonding surface 102A as the flow channel 1021. The flow channel 1021 can be formed using microelectromechanical fine processing techniques or other conventional techniques. Then, the second bonding surface 102A of the second substrate 102 is bonded to the photo-curable adhesive thin layer 103' of the first substrate 101. Since the photocurable adhesive thin layer 103' has been reduced in fluidity after being irradiated by the first lamp 20, when the second substrate 102 is attached to the first substrate 101, the photohardenable adhesive thin layer 103' is received by the first substrate 101. The pressing of the second substrate 102 also does not easily flow into the flow path 1021 of the second bonding surface 102A, so that the flow path 1021 can be prevented from being hindered by the light-hardening adhesive 103 flowing therein. In the above, the second bonding surface 102A of the second substrate 102 has a plurality of microstructures 1022 (see FIG. 5), in addition to the flow channel 1021, when the second substrate 102 and the second substrate 102 After the substrate 101 is bonded, the microstructure 1022 can maintain the second substrate 102 at a certain distance from the first substrate 101, and the distance is also used to prevent the photo-curing adhesive thin layer 103' from being excessively squeezed into the flow path 1021.

Next, as shown in FIG. 6, the pressure is uniformly applied to the unbonded side of the first substrate 101 and the second substrate 102 to ensure that the first substrate 101 and the second substrate 102 can be closely adhered. Thereafter, the photo-curing adhesive thin layer 103' is irradiated with a second luminaire 30. The wattage value of the second luminaire 30 is higher than the wattage value of the first luminaire 20, and in the present embodiment, the second luminaire 30 is, for example, 400 W. The UV lamp was irradiated with a light-hardening adhesive layer 103' for 30 seconds. The light emitted by the second lamp 30 causes the photohardenable adhesive layer 103' to be rapidly cured, and the wafer 10 is completed after the photohardenable adhesive layer 103' is fully cured. In this embodiment, the lamps of different wattages are irradiated with the hardened adhesive thin layer 103' in two stages, but in the art, other wattage lamps can be used to illuminate the light hardening between the two stages. The thin layer 103' is then applied to avoid the occurrence of high mobility of the photohardenable adhesive layer 103' after the first stage of illumination.

The combination method of the wafer 10 of the present embodiment has the following advantages compared to the conventional method of combining wafers:

1. The photocurable adhesive 103 is uniformly and evenly applied onto the first bonding surface 101A of the first substrate 101 by means of two-stage spin coating.

2. The photo-curing adhesive 103 irradiated by the first lamp 20 (low power) reduces the fluidity, so that when the first substrate 101 and the second substrate 102 are bonded, the photo-curing adhesive 103 does not easily flow into the second substrate 102. Inside the flow path 1021.

3. The first substrate 101 and the second substrate 102 which are uniformly pressed cause a higher degree of adhesion of the packaged wafer 10, and the overall structure is more solid.

4. The distance is controlled by the microstructure 1022 between the two substrates to prevent excessive pressing between the two substrates, causing the photo-curing adhesive 103 to flow into the flow path 1021.

Although the present invention has been disclosed in the above preferred embodiments, it is not intended to limit the present invention, and any person skilled in the art can make some changes and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of this creation is subject to the definition of the scope of the patent application attached.

10‧‧‧ wafer

103'‧‧‧Light hardening adhesive thin layer

30‧‧‧second luminaire

Claims (7)

A method for bonding a wafer, comprising: a. providing a first substrate, wherein one side of the first substrate is a first bonding surface; b. forming a photo-hardening on the first bonding surface of the first substrate a thin layer of the agent; c. irradiating the thin layer of the photohardening adhesive with a first lamp to preliminarily cure the thin layer of the photohardening adhesive; d. providing a second substrate, wherein one side of the second substrate is a second bonding surface, the second bonding surface is attached to the first bonding surface of the first substrate; and e. irradiating the thin layer of the photo-curing adhesive with a second lamp, so that The thin layer of the photohardening adhesive is completely cured; wherein the wattage value of the second luminaire is higher than the wattage value of the first luminaire; in step b, the thin layer of the photocurable adhesive is formed by spin coating a first bonding surface of the first substrate, wherein the spin coating is performed in a first stage and a second stage, wherein the first stage is to rotate the first substrate by using a first rotation speed value, The second phase is to rotate the first substrate using a second rotational speed value, the second Speed higher than the first speed value. The method for bonding a wafer according to claim 1, further comprising the step of uniformly applying pressure to the first substrate and the second substrate after bonding. The method for bonding a wafer according to the above aspect, wherein the second bonding surface of the second substrate has a plurality of microstructures, and the microstructure is bonded after the second substrate is bonded to the first substrate The second substrate can be kept at a certain distance from the first substrate. The method of bonding a wafer according to claim 1, wherein at least one flow path is provided on the second bonding surface of the second substrate. The method of bonding a wafer according to any one of the items 1 to 6, wherein the photohardening adhesive is a UV adhesive, and the thin layer of the photohardening adhesive is a thin layer of UV adhesive. The method of bonding a wafer according to claim 1, wherein the first lamp and the second lamp are UV lamps. A method of bonding a wafer according to claim 1, wherein the first lamp has a wattage of 36 watts and the second luminaire has a wattage of 400 watts.