Method for measuring surface pressure of photoetching silicon wafer

Abstract

The invention provides a method for measuring the surface pressure of a photoetching silicon wafer. The method comprises the following steps: S1, preparing a pressure measuring silicon wafer, wherein a plurality of pressure measuring chips are embedded in the pressure measuring silicon wafer; the pressure measuring chip is connected with an external data acquisition system through a micro channel so as to acquire and transmit pressure data in real time; s2, preprocessing; S3, installing a pressure measuring silicon wafer; s5, data acquisition: receiving and recording a signal output by the pressure measuring chip through a data acquisition system, and then converting the signal into an actual pressure value according to a calibration curve of the pressure measuring chip; and S6, data analysis: analyzing the collected pressure data to evaluate the distribution condition and the change trend of the pressure on the surface of the silicon wafer and the possible influence on the quality of the silicon wafer in the photoetching process. The method provided by the invention not only can realize real-time monitoring and quick response, but also is not easily interfered by the photoetching process.

Description

Technical Field

[0001] The invention relates to the technical field of photolithography, and in particular to a method for measuring surface pressure of a photolithography silicon wafer. Background Art

[0002] In the lithography process, pressure measurement on the silicon wafer surface is crucial because it directly affects the lithography quality, chip performance and the reliability of the final product.

[0003] In the existing technology, the surface pressure of the silicon wafer is usually measured by attaching a strain gauge on the surface of the silicon wafer, and the pressure is inferred by measuring the change in the resistance of the strain gauge. This method is easily affected by environmental factors; the measurement accuracy is limited by the performance and pasting quality of the strain gauge; real-time monitoring cannot be achieved; and some technologies use piezoelectric sensors for measurement. However, piezoelectric materials are easily affected by temperature and humidity and have poor stability; complex signal processing circuits are required.

[0004] Based on this, in order to adapt to the development of lithography technology, a method for measuring silicon wafer surface pressure is needed that can perform real-time monitoring, respond quickly, and not be easily disturbed by the lithography process. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for measuring the surface pressure of a photolithography silicon wafer, which is specifically achieved through the following technical solutions:

[0006] A method for measuring surface pressure of a photolithography silicon wafer comprises the following steps:

[0007] S1. Prepare a pressure measuring silicon wafer: The pressure measuring silicon wafer is embedded with a plurality of pressure measuring chips; the pressure measuring chip is connected to an external data acquisition system through a tiny channel to collect and transmit pressure data in real time.

[0008] S2. Pretreatment: Process the pressure measuring silicon wafer to make the surface of the pressure measuring silicon wafer smooth, clean, and free of scratches or contamination;

[0009] S3, installing the pressure measuring silicon wafer: placing the pressure measuring silicon wafer and the silicon wafer to be measured together in the silicon wafer box, and completing the alignment and leveling operations;

[0010] S4, executing a photolithography process: making the pressure measuring silicon wafer and the silicon wafer to be tested perform the same exposure process; during this process, the pressure measuring chip in the pressure measuring silicon wafer measures and collects the pressure of the area to be tested, and converts it into an electrical signal for output;

[0011] S5, data acquisition: receiving and recording the signal output by the pressure measuring chip through the data acquisition system, and then converting it into the actual pressure value according to the calibration curve of the pressure measuring chip;

[0012] S6. Data analysis: Analyze the collected pressure data to evaluate the distribution of pressure on the silicon wafer surface during the lithography process, its changing trend, and its possible impact on the quality of the silicon wafer.

[0013] Optionally or preferably, the pressure measuring silicon wafer has the same shape and size as the silicon wafer to be measured; the diameter of the pressure measuring silicon wafer is 50-600 mm.

[0014] Optionally or preferably, the pressure measuring chip comprises a supporting layer, a sealing layer, a resonance layer and a diaphragm layer; a cavity is arranged on one side of the sealing layer close to the resonance layer, the resonance layer comprises a resonance beam, and the diaphragm layer comprises a pressure-sensitive diaphragm.

[0015] Optionally or preferably, the pressure measuring chips are embedded in the side pressure silicon wafer in an equidistant array arrangement.

[0016] Optionally or preferably, the pressure measuring chip connects the collected pressure change data to an external data acquisition system via optical fiber in the form of an optical signal.

[0017] Optionally or preferably, before analyzing the collected data, the data is filtered, denoised, and calibrated.

[0018] Based on the above technical solution, the present invention provides a method for measuring the surface pressure of a photolithography silicon wafer, which can produce the following technical effects:

[0019] (1) High measurement accuracy: By embedding a pressure measuring chip in the pressure measuring silicon wafer and accurately setting the parameters of the lithography machine and controlling the environment, the tiny pressure changes on the silicon wafer surface during the lithography process can be accurately captured;

[0020] (2) The chip to be tested is embedded in the silicon wafer when it is manufactured, and there is no need to open a mounting groove on the surface of the silicon wafer, thereby avoiding damage to the surface of the silicon wafer and possible contamination;

[0021] (3) Through the embedded multiple pressure measuring chips, multi-point synchronous measurement is achieved to obtain more comprehensive pressure distribution information on the silicon wafer surface;

[0022] (4) Measurements made using an array of pressure measuring chips can avoid measurement errors caused by the environment as much as possible and improve measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0024] Figure 1 The figure is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0025] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Embodiment 1:

[0028] like Figure 1 As shown:

[0029] The present invention provides a method for measuring surface pressure of a photolithography silicon wafer, comprising the following steps:

[0030] S1. Prepare a pressure measuring silicon wafer: a plurality of pressure measuring chips are embedded in the pressure measuring silicon wafer; the pressure measuring chip is connected to an external data acquisition system through a tiny channel to collect and transmit pressure data in real time; specifically, the pressure measuring silicon wafer has the same shape and size as the silicon wafer to be tested; the diameter of the pressure measuring silicon wafer is 50-600mm; the pressure measuring chip includes a support layer, a sealing layer, a resonance layer and a diaphragm layer; the sealing layer is provided with a cavity on one side close to the resonance layer, the resonance layer includes a resonance beam, and the diaphragm layer includes a pressure sensitive diaphragm. This structure can improve the stability and measurement accuracy of the pressure measuring chip; further, the pressure measuring chip is embedded in the side pressure silicon wafer in an equidistant array arrangement to ensure that the chips can be evenly distributed in the key areas of the silicon wafer.

[0031] S2. Pretreatment: Process the pressure measuring silicon wafer to make the surface of the pressure measuring silicon wafer smooth, clean, and free of scratches or contamination; specifically, when cleaning the surface of the silicon wafer, use a suitable cleaning agent and process to remove impurities such as grease and dust on the surface.

[0032] S3. Install the pressure measuring silicon wafer: Place the pressure measuring silicon wafer together with the silicon wafer to be tested in the silicon wafer box, and complete the alignment and leveling operations; further, it also includes a comprehensive calibration of the measurement system, including zero point calibration, sensitivity calibration and linearity calibration, etc., to ensure the accuracy of the measurement results.

[0033] S4, executing a photolithography process: making the pressure measuring silicon wafer and the silicon wafer to be tested perform the same exposure process; during this process, the pressure measuring chip in the pressure measuring silicon wafer measures and collects the pressure of the area to be tested, and converts it into an electrical signal for output;

[0034] S5, data acquisition: receiving and recording the signal output by the pressure measuring chip through the data acquisition system, and then converting it into the actual pressure value according to the calibration curve of the pressure measuring chip;

[0035] S6. Data analysis: Analyze the collected pressure data to evaluate the distribution of pressure on the silicon wafer surface during the lithography process, its changing trend, and its possible impact on the quality of the silicon wafer.

[0036] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for measuring surface pressure of a photolithography silicon wafer, characterized in that: The following steps are involved: S1. Prepare a pressure measuring silicon wafer: The pressure measuring silicon wafer is embedded with a plurality of pressure measuring chips; the pressure measuring chip is connected to an external data acquisition system through a tiny channel to collect and transmit pressure data in real time. S2. Pretreatment: Process the pressure measuring silicon wafer to make the surface of the pressure measuring silicon wafer smooth, clean, and free of scratches or contamination; S3, installing the pressure measuring silicon wafer: placing the pressure measuring silicon wafer and the silicon wafer to be measured together in the silicon wafer box, and completing the alignment and leveling operations; S4, executing a photolithography process: making the pressure measuring silicon wafer and the silicon wafer to be measured perform the same exposure process; During this process, the pressure measuring chip in the pressure measuring silicon wafer measures and collects the pressure in the area to be measured, and converts it into an electrical signal for output; S5, data acquisition: receiving and recording the signal output by the pressure measuring chip through the data acquisition system, and then converting it into the actual pressure value according to the calibration curve of the pressure measuring chip; S6. Data analysis: Analyze the collected pressure data to evaluate the distribution of pressure on the silicon wafer surface during the lithography process, its changing trend, and its possible impact on the quality of the silicon wafer.

2. A method for measuring surface pressure of a photolithography silicon wafer according to claim 1, characterized in that: The pressure measuring silicon wafer has the same shape and size as the silicon wafer to be measured; the diameter of the pressure measuring silicon wafer is 50-600 mm.

3. The method for measuring surface pressure of a photolithography silicon wafer according to claim 1, characterized in that: The pressure measuring chip comprises a supporting layer, a sealing layer, a resonance layer and a diaphragm layer; a cavity is arranged on one side of the sealing layer close to the resonance layer, the resonance layer comprises a resonance beam, and the diaphragm layer comprises a pressure sensitive diaphragm.

4. The method for measuring surface pressure of a photolithography silicon wafer according to claim 1, characterized in that: The pressure measuring chips are arranged in an equidistant array and embedded in the side pressure silicon wafer.

5. The method for measuring surface pressure of a photolithography silicon wafer according to claim 1, characterized in that: The pressure measuring chip connects the collected pressure change data to an external data collection system via optical fiber in the form of an optical signal.

6. The method for measuring surface pressure of a photolithography silicon wafer according to claim 1, characterized in that: Before analyzing the collected data, the data is filtered, denoised, and calibrated.

Images