Photolithography development method

Abstract

The present invention relates to the technical field of photolithography, and in particular to a method for photolithography development, comprising the following steps: coating a photoresist on a wafer and exposing the photoresist; then developing the wafer; controlling the rotation of the wafer, and rinsing the wafer after the development process; and drying the wafer after the rinsing process; wherein, during the rinsing process, the wafer alternately changes between a first rotation speed and a second rotation speed within a preset time. The rotation speed of the wafer is alternately changed in sections to avoid damage to the photoresist surface caused by an excessively high rotation speed of the wafer during the rinsing process.

Description

Technical Field

[0001] The invention relates to the technical field of photolithography, and in particular to a photolithography development method. Background Art

[0002] In the photolithography process, development is an important step in the photolithography process, and the effect of development will directly affect the photolithography results. When the development time is reached, you should immediately use Figure 1 The deionized water rinse procedure shown rinses the wafer. Deionized water not only terminates the development process, but also rinses away the photoresist particles generated during the development process. During the rinsing process, the centrifugal force generated by the wafer rotation also helps remove surface particles.

[0003] At present, when the thickness of the photoresist is relatively thick (greater than 7um), during the development process, reducing the flushing speed may cause the development byproducts to be unable to be thrown out, thereby causing damage to the photoresist surface 100. The specific damage is as follows Figure 2 shown. Summary of the invention

[0004] In order to overcome the above technical problems, the present invention provides a photolithography development method, aiming to solve at least one of the above technical problems.

[0005] In order to achieve the above object, the present invention provides a method for photolithography development, comprising the following steps:

[0006] applying photoresist on the wafer;

[0007] exposing and developing the wafer;

[0008] Control the wafer rotation and rinse the wafer after development;

[0009] Drying the rinsed wafer;

[0010] During the rinsing process, the wafer alternates between a first rotation speed and a second rotation speed within a preset time. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0012] Figure 1 The rotation speed of the wafer at different stages in the prior art;

[0013] Figure 2 For passing Figure 1Schematic diagram of the surface structure of the photoresist after treatment;

[0014] Figure 3 This is a schematic diagram of the surface structure of the photoresist after being processed in an embodiment of the present application. DETAILED DESCRIPTION

[0015] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0016] Various structural schematic diagrams according to embodiments of the present disclosure are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may further design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0017] In the context of the present disclosure, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element or an intervening layer / element may exist therebetween. In addition, if a layer / element is "on" another layer / element in one orientation, the layer / element may be "below" the other layer / element when the orientation is reversed.

[0018] An embodiment of the present invention relates to a method for photolithography development, the method comprising the following steps:

[0019] Step 1: Apply photoresist on the wafer;

[0020] It should be noted that before applying photoresist to the wafer, the wafer can be subjected to a viscosity enhancement treatment. Specifically, a viscosity enhancer is applied on the surface of the wafer. The viscosity enhancer used in the present invention is VM652. The coating method is a spray-rotate method. First, the wafer is rotated at a low speed for a certain period of time, so that the VM652 viscosity enhancer can cover the entire wafer in a short time. After the spraying is completed, the wafer is stationary, and then the wafer is infiltrated with VM652 for a certain period of time. Sufficient infiltration can reduce the number of bubble defects. After the infiltration is completed, the wafer is rotated at a high speed for a certain period of time to throw most of the VM652 out of the wafer.

[0021] The preferred time for VM652 soaking is 15-25 seconds, which is more effective in reducing bubbles.

[0022] In one embodiment of the present invention, the spraying time is 25 seconds, the soaking time is 20 seconds, the spin-drying speed is 1500RPM, and the spin-drying time is 15 seconds. In other embodiments, the soaking time can also be 15 seconds or 25 seconds. Those of ordinary skill in the art can use other parameters as needed.

[0023] The coating of photoresist may include the following steps:

[0024] First, the wafer is rotated at a certain speed, and high-viscosity polyimide is sprayed on the wafer for a certain time. In the embodiment of the present invention, the time for coating is 20-25 seconds. Compared with the traditional process, the present invention reduces the coating time, can reduce the glue consumption of a single wafer, and can eliminate the adhesive residue on the back of the wafer. Then the wafer is allowed to stand for a certain time. In the embodiment of the present invention, the time for the wafer to stand is 25-35 seconds. Increasing the standing time can reduce the number of bubble defects on the surface of the wafer. Then the wafer is subjected to a glue-smoothing operation. The glue-smoothing operation is divided into three steps. First, the wafer speed is adjusted to a lower value, and the first step of glue-smoothing is performed for a certain time; then the wafer speed is adjusted to a higher speed, and the second step of glue-smoothing is performed for a certain time; finally, the wafer speed is adjusted to an intermediate speed, and the third step of glue-smoothing is performed for a certain time, and the glue-smoothing operation ends. In one embodiment of the present invention, the speed of the wafer during spraying is 500RPM, and the time is 20s. The speed of the glue spreading is divided into three steps, and the speed and time are: 800RPM, time 17s; 4000RPM, time 5s; 1500RPM, time 55s, and standing time 30s. In other different thick film processes, those skilled in the art can use other parameters as needed. When the wafer speed in the first step is less than the wafer speed in the third step and less than the wafer speed in the second step, bubbles can be further reduced and the yield rate can be improved.

[0025] As an example, the photoresist layer may be a positive photoresist layer. After the positive photoresist layer is exposed, the photoresist in the exposed area may be removed using a developer.

[0026] Step 2: Expose and develop the wafer. During the exposure process, an I-line photolithography machine is used for exposure, and the exposure wavelength is 365nm. During the development process, the wafer is in a stationary state;

[0027] Specifically, the wafer is controlled to rotate at a certain speed, and the developer is sprayed onto the wafer at the same time; further, as shown in Table 1, the rotation speed of the wafer is adjusted to 700 rpm, and then the wafer is maintained at 700 rpm for a period of time, and then reduced to 70 rpm, and then reduced to 30 rpm. In this way, during the process of the sudden drop in speed, the developer can be evenly spread to the photoresist on the entire surface of the wafer, and the excess developer can be thrown out, and the amount of developer accumulated on the surface of the photoresist can be controlled, thereby reducing the probability of development defects during the development process.

[0028] After the rotation speed of the wafer is reduced to 30rpm, the rotation speed of the wafer continues to decrease until the wafer returns to a stationary state. At this time, the photoresist on the pattern part of the wafer has been initially dissolved and maintained for a period of time.

[0029] Step 3: Use deionized water to rinse the wafer after development. During the rinsing process, control the wafer to rotate at a speed of 1200 rpm. After maintaining for a period of time, reduce it to 500 rpm. After maintaining for a period of time, increase it to the first speed of 1500 rpm. After maintaining for 5 seconds, reduce it to the second speed of 500 rpm. After maintaining for another 5 seconds, increase it to the first speed of 1500 rpm. Repeat this process 5 times, alternating between the two, and complete the rinsing of the wafer.

[0030] Table 1: Wafer rotation speed at different stages

[0031] Time(s) Speed ​​(rpm) 1.0 700 0.5 700 1.5 700 2.0 70 2.5 30 5.0 0 5.0 0 39.0 0 5.0 0 5.0 1200 10.0 500 5.0 1500 5.0 500 5.0 1500 5.0 500 5.0 1500

[0032] Step 4: Dry the rinsed wafer.

[0033] Compared with the prior art, the present embodiment changes the rotation speed of the wafer in stages during the rinsing process, thereby preventing the rotation speed of the wafer from damaging the photoresist surface during the rinsing process. Figure 2 As shown, after being processed by this embodiment, the photoresist surface on the wafer is not damaged.

[0034] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for photolithography development, characterized in that: The following steps are involved: applying photoresist on the wafer; exposing and developing the wafer; The spraying of the developer comprises: controlling the wafer to rotate at a rotation speed of 700 rpm, spraying the developer onto the wafer, then maintaining the wafer at 700 rpm for a period of time, reducing the speed to 70 rpm, and then reducing the speed to 30 rpm; Control the wafer rotation and use deionized water to rinse the wafer after development; Drying the rinsed wafer; Wherein, during the rinsing process, the wafer alternates between the first speed and the second speed within a preset time, alternating 5 times; The time for alternating the first speed and the second speed is the same; The preset time is 25-35s, the first rotation speed is 1000-1500rpm, and the second rotation speed is 500-800rpm.

2. The photolithography development method according to claim 1, characterized in that: The time for alternating the first speed and the second speed is 5 seconds.

3. The photolithography development method according to claim 1 or 2, characterized in that: During the development process, the wafer is in a stationary state.

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