A sensor die bonding and gluing process

Abstract

A sensor solid crystal glue pressing process, one end of the core pressing tool used is the core pressing end, and the other end is the handheld end. An annular glue pressing head is arranged at the axial center position of the core pressing end, the inner diameter of the annular glue pressing head is larger than the side length of the chip silicon cup, and the outer diameter of the annular glue pressing head is less than or equal to the side length of the chip end face; an annular limit outer edge is arranged on the outer periphery of the core pressing end, and the inner diameter of the annular limit outer edge matches the outer diameter of the sensor base; the height of the annular glue pressing head h = H-[d+(0.18~0.22mm)], where H is the distance from the upper end face of the base gauge pressure hole to the upper end face of the sensor base, and d is the chip height. The present invention provides a sensor solid crystal glue pressing process, in the production process of the gauge pressure sensor, the chip is sealed and fixed, and the process can simultaneously meet the requirements of not touching the pressure sensing surface of the chip, ensuring the sealing of the internal cavity, and controlling the thickness of the glue layer at the bottom of the chip.

Description

Technical Field

[0001] The invention relates to a production process of a pressure sensor, and in particular to a die bonding and gluing process for producing a gauge pressure sensor. Background Art

[0002] Most of the silicon-based chips used in the current MEMS piezoresistive pressure sensors in China and abroad adopt SOI structure, that is, a silicon layer with a Wheatstone bridge is bonded on a glass substrate, and the silicon layer includes a silicon cup that can produce pressure deformation. Because it is relatively sensitive to pressure, its pressure sensing range should not be touched when fixing the chip. At the same time, when manufacturing gauge pressure sensors, it is necessary to ensure the sealing of the chip cavity. In addition, the experience summarized in our company's many years of production practice shows that a 0.2mm thick glue layer at the bottom of the chip will make the overall performance of the sensor more stable. At present, there is no mature process that can solve the problem of ensuring the sealing and glue layer thickness at the same time without touching the pressure sensing surface of the chip. Summary of the invention

[0003] The purpose of the present invention is to provide a sensor die bonding and gluing process, in the production process of a gauge pressure sensor, the chip is sealed and fixed with glue, the process can simultaneously meet the requirements of not touching the pressure sensing surface of the chip, ensuring the sealing of the internal cavity, and controlling the thickness of the glue layer at the bottom of the chip.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A sensor die bonding and gluing process, comprising the following method:

[0006] 1) A core pressing tool is manufactured, wherein one end of the core pressing tool is a core pressing end, and the other end is a hand-held end. An annular pressing head is arranged at the axis center of the core pressing end, and the inner diameter of the annular pressing head is larger than the diameter of the chip silicon cup, and the outer diameter of the annular pressing head is smaller than the side length of the end face of the chip; an annular limiting outer edge is arranged on the outer periphery of the core pressing end, and the inner diameter of the annular limiting outer edge matches the outer diameter of the sensor base; the height h of the annular pressing head satisfies formula (1):

[0007] h=H-(d+c) (1)

[0008] Where: H is the distance from the upper end surface of the base gauge hole to the upper end surface of the sensor base;

[0009] d—chip height;

[0010] c—chip bottom glue layer thickness, c=0.18-0.22mm;

[0011] 2) Apply a layer of glue >0.22mm thick around the upper end surface of the gauge pressure hole on the sensor base;

[0012] 3) Then place the chip at the center of the sensor base, align the chip gauge pressure hole with the base gauge pressure hole, and then place the core pressing tool on the sensor base and compact it to make the thickness of the glue layer at the bottom of the chip c = 0.18-0.22mm.

[0013] A core pressing tool used in a sensor solid crystal pressing process, wherein one end of the core pressing tool is a core pressing end, and the other end is a handheld end. An annular pressing head is arranged at the axial center of the core pressing end, the inner diameter of the annular pressing head is greater than the side length of a chip silicon cup, and the outer diameter of the annular pressing head is less than or equal to the side length of the chip end face; an annular limiting outer edge is arranged on the outer periphery of the core pressing end, and the inner diameter of the annular limiting outer edge matches the outer diameter of a sensor base; the height of the annular pressing head is h=H-[d+(0.18-0.22mm)], wherein H is the distance from the upper end face of the base gauge pressure hole to the upper end face of the sensor base, and d is the chip height.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention provides a sensor die bonding and gluing process. In the production process of a gauge pressure sensor, the chip is sealed and fixed with glue. The process can simultaneously meet the requirements of not touching the pressure sensing surface of the chip, ensuring the sealing of the internal cavity, and controlling the thickness of the glue layer at the bottom of the chip.

[0016] The present invention realizes the innovation of the sensor die bonding process, has a simple and reliable production process, uses tooling at a low cost, has good chip protection, and has a high control precision on the chip glue layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural diagram during the implementation of the process of the present invention;

[0018] Figure 2 It is a schematic diagram of the chip structure;

[0019] Figure 3 It is a structural schematic diagram of the core pressing tooling;

[0020] Figure 4 It is a schematic diagram of the overall appearance of the core pressing tooling when in use;

[0021] In the figure: 1-core pressing tool, 2-chip, 3-annular glue pressing head, 4-upper end surface of sensor base, 5-annular limiting outer edge, 6-glue layer, 7-chip silicon layer, 8-chip silicon cup, 9-chip glass substrate, 10-limiting surface in contact with the upper end surface of sensor base, 11-sensor base. DETAILED DESCRIPTION

[0022] The present invention is described in detail below in conjunction with the accompanying drawings, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0023] Embodiment 1:

[0024] like Figure 1-Figure 4 As shown, a sensor die bonding and gluing process, the chip silicon cup 8 is a square with a side length of 1.1 mm, ensuring that the thickness of the glue layer 6 at the bottom of the chip glass base 9 is 0.2 mm, includes the following methods:

[0025] 1) A core pressing tool is manufactured, wherein one end of the core pressing tool is a core pressing end and the other end is a hand-held end. An annular rubber pressing head 3 is arranged at the axial center of the core pressing end, and the inner diameter of the annular rubber pressing head 3 is 1.75 mm and the outer diameter is 2.47 mm. An annular limiting outer edge 5 is arranged on the outer periphery of the core pressing end, and the inner diameter of the annular limiting outer edge 5 matches the outer diameter of the sensor base 11. The height h of the annular rubber pressing head 3 satisfies the formula (1):

[0026] h=H-(d+c) (1)

[0027] Where: H is the distance from the upper end surface of the base gauge hole to the upper end surface of the sensor base;

[0028] d—chip height;

[0029] c—thickness of the glue layer at the bottom of the chip, c=0.2mm;

[0030] 2) Use the annular dispensing method to apply a glue layer >0.22mm thick around the upper end surface of the gauge pressure hole of the sensor base 11;

[0031] 3) Then, the chip 2 is placed at the center of the sensor base 11, so that the gauge pressure hole of the chip 2 is aligned with the gauge pressure hole of the base, and then the core pressing tool 1 is placed on the sensor base 11 and compacted to make the thickness of the adhesive layer 6 at the bottom of the chip 2 c=0.2mm.

[0032] like Figure 3 , Figure 1 As shown, when the core pressing tool 1 is buckled on the upper end of the sensor, due to the radial limiting effect of the annular limiting outer edge 5, the annular glue pressing head 3 can be accurately positioned on the upper end of the chip 2 without touching the pressure sensing surface of the chip, and pressed downward. When the limiting surface 10 in contact with the upper end surface of the sensor base is against the upper end surface of the sensor base 11, the thickness of the glue layer at the bottom of the chip just meets the requirement of 0.2mm, and the installation process of the chip bottom sealing glue is completed at the same time. The invention has a simple process, is easy to operate, has high processing accuracy, is suitable for mass production, and meets product performance requirements.

Claims

1. A sensor die bonding and gluing process, characterized in that: The following methods are included: 1) A core pressing tool is manufactured, wherein one end of the core pressing tool is a core pressing end, and the other end is a hand-held end. An annular pressing head is arranged at the center of the axis of the core pressing end, the inner diameter of the annular pressing head is larger than the side length of the chip silicon cup, and the outer diameter of the annular pressing head is smaller than or equal to the side length of the end face of the chip; an annular limiting outer edge is arranged on the outer periphery of the core pressing end, and the inner diameter of the annular limiting outer edge matches the outer diameter of the sensor base; the height h of the annular pressing head satisfies formula (1): h=H-(d+c) (1) Where: H is the distance from the upper end surface of the base gauge hole to the upper end surface of the sensor base; d—chip height; c—chip bottom glue layer thickness, c=0.18-0.22mm; 2) Apply a layer of glue >0.22mm thick around the upper end surface of the gauge pressure hole on the sensor base; 3) Then place the chip at the center of the sensor base, align the chip gauge pressure hole with the base gauge pressure hole, and then place the core pressing tool on the sensor base and compact it to make the thickness of the glue layer at the bottom of the chip c = 0.18-0.22mm.

2. A core pressing tool used in the sensor die bonding and gluing process as claimed in claim 1, characterized in that: One end of the core pressing tool is the core pressing end, and the other end is the hand-held end. An annular glue pressing head is arranged at the axial center position of the core pressing end. The inner diameter of the annular glue pressing head is larger than the diameter of the chip silicon cup, and the outer diameter of the annular glue pressing head is smaller than the side length of the chip end face. An annular limiting outer edge is arranged on the outer periphery of the core pressing end, and the inner diameter of the annular limiting outer edge matches the outer diameter of the sensor base. The height of the annular glue pressing head is h=H-[d+(0.18~0.22mm)], wherein H is the distance from the upper end face of the base gauge pressure hole to the upper end face of the sensor base, and d is the chip height.

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