CN1261825C - Exposure system and method with group compensation capability - Google Patents

Abstract

An exposure system with group compensation capability includes a lot classification database, a compensation unit and a first exposure device. The lot classification database records the group classification of the corresponding lot wafer. The compensation unit obtains the group classification of the corresponding lot wafers from the lot classification database, retrieves the corresponding group compensation values according to the group classification, and compensates the corresponding alignment parameters according to the group compensation values. The first exposure device uses the compensated alignment parameters to perform a back-end process including alignment and exposure operations on the lot wafers.

Description

Exposure system and method with group compensation capability

technical field

The present invention relates to an exposure system and method, in particular to an exposure machine suitable for semiconductor manufacturing, which can classify batches of goods according to the machine and mask of the front-end process, and provide groups for the back-end process. Exposure system and method for group compensation.

Background technique

In semiconductor manufacturing, the photolithography process in the yellow light area is one of the most important steps in the entire process. The components related to the structure of semiconductor products, such as the pattern (Pattern) and dopants (Dopants) of each layer of film, must be determined by the lithography process. Therefore, the semiconductor manufacturing industry usually uses the number of lithography times required for a process or the number of masks required to represent the difficulty of the corresponding product process. As mentioned above, due to the complex manufacturing process of the exposure equipment in the yellow light area, the exposure equipment is usually one of the main bottlenecks in the overall semiconductor manufacturing process.

In order to improve the resolution of the exposure, the exposure machine usually uses the "repeat and step (Step and Repeat)" method for exposure, so the exposure machine can also be called a stepper (Stepper). The exposure machine passes the light source through the mask, and then shrinks it according to an appropriate ratio before irradiating it on a part of the wafer. Therefore, the exposure of the entire wafer must be exposed repeatedly and repeatedly "one by one" to fully expose the entire wafer. The exposure steps required for the wafer are completed.

FIG. 1 shows an example of the layer alignment relationship between the back-end process and the front-end process. In this example, different back-end processes: back-end process 1 (101), back-end process 2 (102) and back-end process 3 (103) must be aligned with the layers made by the front-end process 100. layers. Since a semiconductor product manufacturing process usually requires multiple levels of pattern transfer to complete, however, one wafer exposure step only completes the transfer of one layer of pattern. It is necessary to accurately align the exposure position of "every piece" on the wafer, and it is also necessary to accurately align each mask with the position of the wafer when exposing different layers of patterns.

Since the exposure machine exposes each batch of wafers (Lot), the correct parameter values (Recipe) for exposure and alignment will have a slight drift (deviation), so after each batch is executed After the exposure of the wafer, it is necessary to measure the exposed wafer, and obtain the error value as the basis for correcting the parameter value of the exposure machine when the next batch of wafers are exposed. Generally speaking, the above correction actions are performed manually or through a feedback (Feed Back) system, such as the exposure method and system for automatic feedback correction disclosed in Taiwan Patent Publication No. 516099 to perform related compensation calculations.

However, because the products manufactured by the machines and masks used in the front-end process have an impact on the alignment compensation trend of the back-end process, the calculation method of the above-mentioned feedback system is a hybrid calculation, that is, it does not consider the front-end process. The impact of the machine and the mask, therefore, the alignment compensation parameters of different front-end process products will affect each other, resulting in the instability of the compensation calculation, and it is easy to increase the rework rate (Rework Rate), thereby reducing the overall production capacity.

Contents of the invention

The main purpose of the present invention is to provide an exposure machine suitable for semiconductor manufacturing, which can classify batches according to the machine and mask of the front-end process, and provide an exposure system and method for group compensation in the back-end process.

In order to achieve the above object, it can be achieved by the exposure system and method with group compensation capability provided by the present invention. An exposure system with group compensation capability according to an embodiment of the present invention includes a batch classification database, a compensation unit and a first exposure device. The group classification of the corresponding batch of wafers is recorded in the batch classification database. The compensation unit obtains the group classification of the corresponding batch of wafers from the batch classification database, retrieves the corresponding group compensation value according to the group classification, and compensates the corresponding alignment parameters according to the group compensation value. The first exposure device uses the compensated alignment parameters to perform back-end processes including alignment and exposure operations on the batch of wafers.

According to the exposure method with group compensation capability according to the embodiment of the present invention, firstly, the group classification of the corresponding batch of wafers is obtained. Next, the group compensation values of the corresponding batch of wafers are retrieved according to the group classification, and the corresponding alignment parameters are compensated according to the group compensation values. Finally, the back-end process including alignment and exposure is performed on the lot of wafers using the compensated alignment parameters.

Among them, the group classification of the corresponding batch of wafers is determined according to the machines and masks used in the front-end process. In addition, after the alignment and exposure operations of the batch of wafers are completed, the group classification of the corresponding batch of wafers is updated.

Description of drawings

FIG. 1 is an example showing the layer alignment relationship between the back-end process and the front-end process;

FIG. 2 shows the system architecture of an exposure system with group compensation capability according to an embodiment of the present invention;

FIG. 3 is a diagram showing the operation flow of an exposure method with group compensation capability according to an embodiment of the present invention.

Symbol Description:

100-Front-end process

101-Back-end process 1

102-Back-end process 2

103-Back-end process 3

200-second exposure device

210-first exposure device

211 - alignment unit

212-exposure unit

220-Lot classification database

230-compensation unit

231-Group complement database

S301, S302, ..., S305-operation steps

Detailed ways

FIG. 2 shows the system architecture of an exposure system with group compensation capability according to an embodiment of the present invention. The exposure system with group compensation capability according to the embodiment of the present invention includes a first exposure device 210 , a second exposure device 200 , a batch classification database 220 and a compensation unit 230 .

The first exposure device 210 has an alignment unit 211 and an exposure unit 212 . The alignment unit 211 is used to align parameters according to relevant alignment parameters, such as X-axis displacement (Offset_X), Y-axis displacement (Offset_Y), X-axis irradiation size (Shot Scaling X), Y-axis irradiation size (Shot ScalingY), shot orthogonal (Shot Orthogonality), and Shot Rotation (Shot Rotation) and other parameters are used to perform alignment actions and alignment actions between layers when scanning/stepping exposure of a layer is started for the wafer. The exposure unit 212 is used to expose the wafer after the alignment unit 211 is aligned to a correct position. After the wafer is aligned and exposed by the alignment unit 211 and the exposure unit 212 , it can be sent to other semiconductor manufacturing processes for related processing.

It should be noted that the second exposure device 200 may have a device structure and composition similar to that of the first exposure device 210, and in a common case, the second exposure device 200 and the first exposure device 210 may be the same exposure machine tower. In this embodiment, the second exposure device 200 represents the exposure tool for the front-end process of the corresponding batch of wafers, and the first exposure device 210 represents the exposure tool for the back-end process of the corresponding batch of wafers.

The group classification of the corresponding batch of wafers is recorded in the batch classification database 220 . Wherein, the group classification of the corresponding batch of wafers is determined according to the machines and masks used in the front-end process, and each batch of wafers that have passed the front-end process will be registered by the second exposure device 200 in the batch classification database 220 Record its group classification in .

The compensation unit 230 has a group complement database 231 . The group complement database 231 is used to record group compensation values corresponding to different group categories. The compensation unit 230 can obtain the group classification of the corresponding batch of wafers from the batch classification database 220, retrieve the corresponding group compensation value from the group compensation value database 231 according to the group classification, and perform the first exposure according to the group compensation value. The corresponding alignment parameters in device 210 are compensated. The first exposure device 210 can then use the compensated alignment parameters to perform back-end processes including alignment and exposure operations on the batch of wafers.

FIG. 3 shows the operation flow of the exposure method with group compensation capability according to an embodiment of the present invention. First, in step S301 , the compensating unit 230 acquires the group classification corresponding to the batch of wafers to be processed in the first exposure device 210 from the batch classification database 220 . It is worth noting that after the batch of wafers is processed by the front-end process in the second exposure machine 200, the second exposure machine 200 will determine the group corresponding to the batch of wafers according to the machine and mask it uses. Classify, and update it in the batch classification database 220.

Next, as in step S302, the compensation unit 230 searches the group compensation value corresponding to this batch of wafers from the group compensation value database according to the group classification of the corresponding batch of wafers, and as in step S303, according to the retrieved group The compensation value compensates for corresponding alignment parameters on the first exposure device 210 , such as X-axis displacement, Y-axis displacement, X-axis irradiation size, Y-axis irradiation size, irradiation orthogonality, and irradiation rotation.

Afterwards, in step S304 , the first exposure device 210 uses the compensated alignment parameters to perform back-end processes including alignment and exposure operations on the batch of wafers. Finally, after the batch of wafers completes the back-end process including alignment and exposure operations, as in step S305, the first exposure device 210 updates the group corresponding to the batch of wafers according to the tools and masks used in the back-end process Group classification.

Therefore, the exposure system and method with group compensation capability proposed by the present invention can classify batches of goods according to the machines and masks used in the front-end process, so that the compensation mechanisms of different front-end process products can be independently calculated, and later The group compensation function is provided in the terminal process, thereby reducing the instability of the traditional compensation value calculation, thereby reducing the rework rate and improving the overall production capacity.

Claims (6)

1. exposure system with group compensating capacity, it is characterized in that: described exposure system comprises:

The parcel taxonomy database writes down a group group categories of corresponding parcel wafer;

One compensating unit, by this unit of cargo taxonomy database obtain mutually should the unit of cargo wafer this group's classification, according to this group systematic searching mutually should the unit of cargo wafer group's offset, and aim at parameter according to this group's offset for corresponding one and compensate, wherein this group's classification that mutually should the unit of cargo wafer is to determine with light shield according to the board that this front end processing procedure uses;

One first exposure device, this alignment parameter behind the using compensation comprise a rear end processing procedure of aiming at exposure operation for this unit of cargo wafer; And

One second exposure device, in order to carrying out a front end processing procedure of this unit of cargo wafer, this group's classification that decision mutually should the unit of cargo wafer, and will be mutually should the unit of cargo wafer this group's sort pass to this unit of cargo taxonomy database.

2. the exposure system with group compensating capacity according to claim 1 is characterized in that: this first exposure device in this unit of cargo wafer finish aim at exposure operation after, upgrade in this unit of cargo taxonomy database mutually should the unit of cargo wafer this group's classification.

3. the exposure system with group compensating capacity according to claim 2 is characterized in that: this first exposure device be the board that uses according to this rear end processing procedure with light shield upgrade in this unit of cargo taxonomy database mutually should the unit of cargo wafer this group classify.

4. the exposure method with group compensating capacity comprises the following steps:

Carry out a front end processing procedure of this unit of cargo wafer with an exposure device, and a group group categories that decision mutually should the unit of cargo wafer, wherein this group's classification that mutually should the unit of cargo wafer is to determine with light shield according to the board that this front end processing procedure uses;

Obtain mutually should the unit of cargo wafer this group's classification;

According to this group systematic searching mutually should the unit of cargo wafer group's offset;

Compensate for corresponding at least one aligning parameter according to this group's offset; And

This alignment parameter behind the using compensation comprises a rear end processing procedure of aiming at exposure operation for this unit of cargo wafer.

5. the exposure method with group compensating capacity according to claim 4, more comprise this unit of cargo wafer finish aim at exposure operation after, upgrade mutually should the unit of cargo wafer this group's classification.

6. the exposure method with group compensating capacity according to claim 5, wherein this group's classification that mutually should the unit of cargo wafer is to upgrade according to board and light shield that this rear end processing procedure uses.

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