CN100372088C - Automatic bonding method for MEMS high temperature pressure sensor - Google Patents

Abstract

The invention provides an automatic bonding method for a MEMS high temperature pressure sensor. It chooses an automatic bonding machine consisting of a table, a logistics table set on the table, an operator, a heating furnace and a microscope for automatic bonding; the operator of the automatic bonding machine is installed in a 4-degree-of-freedom operation controlled by 4 axes On the manual worktable, the heating furnace is installed on a 2-DOF positioning table controlled by 2 axes, and the microscope is installed on a microscope auto-focusing workbench including an axis that can move up and down. The invention is based on the high-precision and non-contact measurement of microscopic vision, and realizes the high-precision alignment operation of the MEMS high-temperature pressure sensor whether it is the front or the back; fusion of visual/micro-force sense information realizes high-precision, non-destructive alignment of chips and glass substrates Grabbing and handling; the high degree of automation of the equipment enables it to have batch manufacturing capabilities and improve production efficiency.

Description

Automatic bonding method for MEMS high temperature pressure sensor

(1) Technical field

The invention relates to a sensor processing method, in particular to a sensor electrostatic bonding method.

(2) Background technology

Silicon-glass electrostatic bonding technology is widely used in the manufacture of pressure sensors, and plays an important role in the fields of MEMS and IC manufacturing. It is also an important process in the manufacturing process of MEMS high temperature pressure sensors. When bonding MEMS high-temperature pressure sensors, whether it is front-side sensitive or reverse-sensitive. The center of the sensitive circuit must be aligned with the center of the pressure guiding hole. However, the electrostatic bonding operation in MEMS high-temperature pressure sensors is currently manual. Compared with the automatic anode bonding technology, the current manual bonding operation has the following deficiencies and defects: 1. The alignment accuracy is low, and the center of the chip sensitive circuit and the glass-based pressure guiding hole cannot be accurately aligned, especially on the reverse side. When the sensor is bonded, it affects the performance of the sensor. 2. Poor consistency, manual work leads to poor consistency of sensor performance. 3. The efficiency is low, which limits the mass production of MEMS high-temperature pressure sensors.

(3) Contents of the invention

The object of the present invention is to provide an automatic bonding method for MEMS high-temperature pressure sensors that can improve high-precision alignment in the silicon-glass anode bonding process of MEMS high-temperature pressure sensors, improve product quality, and improve production efficiency.

The purpose of the present invention is achieved like this: it selects the automatic bonding machine that is made up of table top, the logistics table that is arranged on table top, operator, heating furnace and microscope; The 4-degree-of-freedom operator's workbench, the heating furnace is installed on the 2-degree-of-freedom positioning workbench controlled by 2 axes, and the microscope is installed on the microscope auto-focusing workbench including the axis that can move up and down;

1. After the sensor chip and the glass substrate are ultrasonically cleaned, they are respectively placed on the carrier tray, placed on the logistics table, and the heating furnace is heated to 420°C;

2. System initialization, start the operator, rotate to the top of the logistics table, and under the control of the micro force sensor, grab the sensor chip without damage;

3. Move the positioning workbench so that the first heating point of the heating furnace with three heating points is located in the center of the microscope field of view, rotate the operator, carry the sensor chip under the microscope, and place it on the first heating point under the control of the micro force sensor. hot spot;

4. Under the servo control of microscopic vision, through image processing and recognition, control the movement of the positioning table so that the center of the sensitive circuit of the sensor chip is located in the center of the field of view;

5. The operator rotates to the top of the logistics table, and under the control of the micro-force sensor, the glass substrate is grasped without damage;

6. Rotate the operator to move the glass substrate under the microscope;

7. Under the servo control of microscopic vision, through image processing and recognition, the movement of the operator is controlled, so that the center of the pressure guiding hole of the glass substrate is located in the center of the field of view;

8. Under the control of the micro force sensor, place the glass substrate vertically downward on the sensor chip. When the two are just in contact, apply a DC voltage of 1200V, the positive electrode is connected to the sensor chip, the negative electrode is connected to the glass substrate, and the bonding starts. ;

9. The packaging head is pressed down on the glass substrate, loaded, and the operator withdraws at the same time, for the bonding operation of the second sensor;

By analogy, when the operator withdraws from the third heating point, the first sensor has been bonded, the operator grabs it out, puts it on the logistics table, and then performs the bonding operation of the fourth sensor. Such a cycle realizes the automatic bonding operation process of the sensor.

In order to achieve high-precision alignment in the silicon-glass anode bonding process of MEMS high-temperature pressure sensors, improve product quality, and improve production efficiency at the same time, the present invention is oriented to batch manufacturing of MEMS sensors, and selects a computer-based control device with batch manufacturing functions. Automatic anode technology This technology has the following advantages:

1. High-precision, non-contact measurement based on microscopic vision, which realizes high-precision alignment of MEMS high-temperature pressure sensors on both the front and back sides;

2. Integrate visual/micro-force sense information to realize high-precision, non-destructive grasping and handling of chips and glass substrates;

3. The high degree of automation of the equipment makes it capable of batch manufacturing and improves production efficiency.

(4) Description of drawings

Fig. 1 is the structural representation of automatic bonding machine of the present invention;

Fig. 2 is the front view of automatic bonding machine of the present invention;

Fig. 3 is the top view of Fig. 1;

Fig. 4 is a left side view of Fig. 1 .

(5) Specific implementation methods

The present invention is described in more detail below in conjunction with accompanying drawing example:

The MEMS high-temperature pressure sensor automatic bonding machine consists of a table top 1 on which a logistics table 2, an operator 3, a heating furnace 4 and a microscope 5 are arranged. The manipulator is installed on the manipulator table with 4 degrees of freedom for precise movement in X, Y, Z and W directions controlled by axes I, II, III and IV. The 4-degree-of-freedom manipulator workbench is used to control the positioning movement of the manipulator to realize the grabbing and handling of chips, glass substrates and bonded finished products; the heating furnace is installed on the axis V and VI controlled , Y two aspects of precise movement of the 2 degrees of freedom positioning on the table. The 2-degree-of-freedom positioning table is used to control the precise movement of the heating furnace along the X and Y directions and to realize the automatic alignment of the silicon wafer and the glass substrate with the aid of image vision; the microscope is installed on the belt axis VII that can move precisely in the Y direction Microscope auto-focus workbench. The microscope described therein is a variable magnification microscope. Microscope automatic focusing workbench is used to control the microscope with variable magnification, so as to constitute a zoom microscopic vision system.

The working process of the present invention is further described below:

1. After ultrasonic cleaning, the chip and the substrate are placed on the carrier tray and placed on the logistics table, and the heating furnace is heated to 420°C;

2. System initialization, start the operator, rotate to the top of the logistics table, and under the control of the micro force sensor, grab the sensor chip without damage;

3. Move and position the workbench so that the first heating point of the heating furnace with 3 heating points is located in the center of the field of view of the microscope. Rotate the operator, move the chip under the microscope, and place it at the first heating point under the control of the micro force sensor;

4. Under the servo control of microscopic vision, through image processing and recognition, control the movement of the positioning table so that the center of the chip sensitive circuit is located in the center of the field of view;

5. Rotate to the top of the logistics table, and grasp the glass substrate without damage under the control of the micro-force sensor;

6. Rotate the operator to move the chip under the microscope;

7. Under the servo control of microscopic vision, through image processing and recognition, the movement of the operator is controlled, so that the center of the pressure guiding hole of the glass substrate is located in the center of the field of view;

8. Under the control of the micro-force sensor, place the glass substrate vertically downward on the chip. When the two are just in contact, apply a DC voltage of 1200V, the positive electrode is connected to the chip, the negative electrode is connected to the glass substrate, and the bonding begins;

9. The packaging head is pressed down onto the glass substrate and loaded. At the same time, the operator is withdrawn for the bonding operation of the second sensor;

10. By analogy, when the operator withdraws from the third heating point, the first sensor has been bonded, the operator grabs it out, puts it on the logistics table, and then performs the bonding of the fourth sensor Industry. Such a cycle realizes the automatic bonding operation process of the sensor.

Various tests, including the motion accuracy of each axis table, image alignment accuracy and micro force sensor index test results are as follows:

Operator Workbench Test Results

name Test items x-axis y-axis z-axis w axis workbench Movement stroke(mm) 50mm 50mm 10mm 274° Repeat positioning accuracy (μm) 1.5μm 1.5μm 1.5μm 0.015° Motion Resolution (μm) 0.5μm 0.5μm 0.5μm 0.005°

Positioning workbench test results

name Test items x-axis y-axis workbench Movement stroke (mm) 80mm 10mm Repeat positioning accuracy (μm) 1.5μm 1.5μm Motion resolution (μm) 0.5μm 0.5μm

Microscope automatic focusing workbench test results

name Test items Technical indicators workbench Movement stroke(mm) 20mm Repeat positioning accuracy (μm) 1.5μm Motion Resolution (μm) 0.5μm

Inspection results of microscopic vision system (visual positioning accuracy)

name Test items Technical indicators Test results objective lens Positioning resolution (μm) 4.0μm 3.81 3.79 3.80 3.81 3.80

Micro force sensor test results

name Range (mN) Accuracy (%F.S) Resolution (mN) One-dimensional force sensor 3000 0.5% 5

Claims (1)

1. A MEMS high-temperature pressure sensor automatic bonding method is characterized in that: it selects an automatic bonding machine composed of a table top, a logistics platform arranged on the table top, an operator, a heating furnace and a microscope; the operation of the automatic bonding machine The hand is installed on the 4-DOF manipulator table controlled by 4 axes, the heating furnace is installed on the 2-DOF positioning table controlled by 2 axes, and the microscope is installed on the microscope automatic focusing including the axis that can move up and down on the workbench; (1) After the sensor chip and the glass substrate are ultrasonically cleaned, they are respectively placed on the carrier tray, placed on the logistics table, and heated to 420°C in the heating furnace; (2) Initialize the system, start the operator, rotate to the top of the logistics platform, and grasp the sensor chip without damage under the control of the micro force sensor; (3) Move the positioning workbench so that the first heating point of the heating furnace with three heating points is located in the center of the microscope field of view, rotate the operator, transport the sensor chip under the microscope, and place it under the control of the micro force sensor. 1 at the heating point; (4) Under the servo control of microscopic vision, through image processing and recognition, control the movement of the positioning workbench, so that the center of the sensitive circuit of the sensor chip is located in the center of the field of view; (5) The operator rotates to the top of the logistics table, and under the control of the micro-force sensor, the glass substrate is grasped without damage; (6) Rotate the operator to move the glass substrate under the microscope; (7) Under the servo control of microscopic vision, through image processing and recognition, the movement of the operator is controlled, so that the center of the pressure guiding hole of the glass substrate is located in the center of the field of view; (8) Under the control of the micro force sensor, place the glass substrate vertically downward on the sensor chip. When the two are just in contact, apply a DC voltage of 1200V, the positive electrode is connected to the sensor chip, and the negative electrode is connected to the glass substrate. together start; (9) The encapsulation head is pressed down onto the glass substrate, loaded, and the operator is withdrawn at the same time, for the bonding operation of the second sensor; By analogy, when the operator withdraws from the third heating point, the first sensor has been bonded, the operator grabs it out, puts it on the logistics table, and then performs the bonding operation of the fourth sensor. Such a cycle realizes the automatic bonding operation process of the sensor.

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