Carrier plate processing method for improving plate warping

Abstract

The invention discloses a carrier plate processing method for improving plate warpage, comprising the following steps: providing an IC carrier plate substrate, the substrate comprising a front circuit and a back circuit, the front circuit being a high-density circuit, the back circuit being a large copper surface; electroplating the substrate, clamping the substrate by using an electroplating clamping fixture, arranging a clamping jaw for clamping the substrate on the fixture, and adjusting the angle of the clamping jaw to enable the substrate to be stretched in a single direction; electroplating the front side circuit and the back side circuit of the substrate by adopting different jet flow speeds and current densities; wherein high-speed jet flow and high current density are adopted for the front circuit, and low-speed jet flow and low current density are adopted for the back circuit; tempering treatment is carried out after electroplating of the substrate is completed; a mathematical model is established at the position, smaller than 3 mm, of the two sides of warping of the base plate, the compensation angle is calculated through arctan, and the clamping jaw angle of next electroplating is adjusted. The substrate warping can be effectively inhibited, the coating uniformity is improved, the residual stress is reduced, and the reliability of the IC support plate is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of printed circuit board processing technology, and particularly relates to a carrier plate processing method for improving board warping. BACKGROUND

[0002] The description in this part only provides background information related to the present application disclosure, and does not constitute prior art.

[0003] With the development of high-performance computing and high-speed communication, IC carrier boards gradually move towards high-density non-fear (HDI) and advanced packaging (2.5D / 3D). However, warping of the substrate is prone to occur during electroplating and compression, which is caused by thermal expansion difference and residual stress, affecting the chip bonding and assembly yield; uneven plating thickness: the difference between the front side circuit and the back side circuit structure leads to uneven current distribution; reliability decreases: long-term stress concentration may cause interface peeling and cracking. The prior art mainly uses a single method to improve, which cannot solve the problems of warping and uneven plating at the same time.

[0004] It should be noted that the above introduction to the technical background is only for the convenience of clearly and completely describing the technical scheme of the present application, and for the convenience of understanding by those skilled in the art. The above technical scheme cannot be considered as known to those skilled in the art only because it is described in the background section of the present application. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a carrier plate processing method for improving board warping, which can effectively suppress substrate warping, improve plating uniformity, reduce residual stress, and improve the reliability of IC carrier boards.

[0006] The present application embodiment discloses a carrier plate processing method for improving board warping, comprising the following steps: providing an IC carrier substrate, the substrate comprising a front side circuit and a back side circuit, the front side circuit being a high-density circuit, and the back side circuit being a large copper surface; electroplating the substrate, using an electroplating clamping fixture to clamp the substrate, the fixture being provided with a clamping jaw for clamping the substrate, and the angle of the clamping jaw being adjusted to make the substrate be stretched in a single direction; differentially adjusting the jet speed and current density for electroplating the front side circuit and the back side circuit of the substrate; wherein high-speed jet and high current density are used for the front side circuit, and low-speed jet and low current density are used for the back side circuit; carrying out tempering treatment after electroplating the substrate; when the warping of the substrate is less than 3mm on both sides, a mathematical model is established, the compensation angle is calculated by using arctan, and the angle of the clamping jaw for the next electroplating is adjusted.

[0007] Further, the substrate warping improvement method for substrate processing, the angle of the clamping jaw is adjusted to 40°-60°.

[0008] Further, the substrate warping improvement method for substrate processing, during the electroplating process of the substrate, the electroplating time is 30 min-120 min, the pulse electroplating and direct current electroplating are adopted, the electroplating bath temperature is 20℃-30℃, the copper sulfate concentration in the electroplating bath is 140 g / L-150 g / L, the sulfuric acid concentration is 160 g / L-180 g / L, and the chloride ion concentration is 10 ppm-30 ppm.

[0009] Further, the substrate warping improvement method for substrate processing, the substrate warping angle formula is: .

[0010] Further, the substrate warping improvement method for substrate processing, in the step of "carrying out electroplating on the front side circuit and the back side circuit of the substrate by adopting different jet flow speed and current density; wherein high speed jet flow and high current density are adopted for the front side circuit, and low speed jet flow and low current density are adopted for the back side circuit", the speed of the high speed jet flow is 1.5 m / s-2.0 m / s, the high current density is 1.8 A / dm 2 , the speed of the low speed jet flow is 0.5 m / s-1.0 m / s, and the low current density is 1.0 A / dm 2 .

[0011] Further, the substrate warping improvement method for substrate processing, in the step of "carrying out tempering treatment after the electroplating of the substrate is completed", the heating rate of the tempering treatment is 1℃ / min-3℃ / min, and the cooling rate of the tempering treatment is 1℃ / min-3℃ / min.

[0012] In summary, the method adopted by the embodiment of the present application has the following advantages: The substrate warping improvement method for substrate processing adjusts the pre-stress introduced by the clamping jaw during the electroplating process, effectively suppresses the warping of the substrate, adopts different jet flow speed and current density for the front side circuit and the back side circuit, improves the uniformity of the plating layer, reduces the residual stress through tempering treatment, improves the structural stability, further improves the warping precision through lattice difference arrangement, and makes the warping control have predictability and high precision by using the mathematical model for auxiliary design.

[0013] In order to further understand the features and technical contents of the present application, please refer to the following detailed description and drawings of the present application. However, the drawings provided are only used for reference and illustration, and are not used to limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present specification or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments described in the present specification, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0015] Fig. 1 is a schematic diagram of the step of the substrate warping improvement method for processing the substrate in the embodiment of the present application; Fig. 2 is a schematic diagram of the substrate warping in the embodiment of the present application.

[0016] The reference numerals of the above drawings are as follows: 1, substrate; h, substrate warping height; w, substrate width. DETAILED DESCRIPTION

[0017] In order to make the person skilled in the art better understand the technical solutions in the present specification, the technical solutions in the embodiments of the present specification will be described clearly and completely below in combination with the drawings in the embodiments of the present specification. Obviously, the described embodiments are only some of the embodiments of the present specification, not all. Based on the embodiments in the present specification, all other embodiments obtained by those skilled in the art without creative labor should be within the protection scope of the present specification.

[0018] The following is to illustrate the embodiments of the present application by specific specific embodiments, and those skilled in the art can understand the advantages and effects of the present application from the disclosure in the present specification. The present application can be implemented or applied by other different specific embodiments, and each detail in the present specification can be modified and changed in various ways based on different views and applications without departing from the concept of the present application. In addition, the drawings of the present application are only simple schematic illustrations, not the depiction according to the actual size, and the prior declaration. The following embodiments will further illustrate the related technical content of the present application in detail, but the disclosed content is not used to limit the protection scope of the present application.

[0019] It should be understood that although the terms "first", "second", "third" and the like may be used herein to describe various components or signals, these components or signals should not be limited by these terms. These terms are mainly used to distinguish one component from another component, or one signal from another signal. In addition, the term "or" used herein may include any one or more combinations of the associated listed items.

[0020] Reference Figs. 1-2As shown, the embodiment of the present application discloses a kind of plate warping improvement carrier plate processing method, comprising the following steps: IC carrier plate substrate 1 is provided, the substrate 1 includes front side circuit and back side circuit, the front side circuit is high-density circuit, and the back side circuit is large copper surface; The substrate 1 is electroplated, the substrate 1 is clamped using electroplating clamping fixture, the fixture is provided with clamping jaw for clamping the substrate 1, the angle of the clamping jaw is adjusted, and the substrate 1 is stretched in single direction; The front side circuit and the back side circuit of the substrate 1 are electroplated using different jet speed and current density;Wherein, high-speed jet and high current density are used for the front side circuit, and low-speed jet and low current density are used for the back side circuit; After the substrate 1 is electroplated, tempering treatment is carried out to release internal residual stress; When the substrate 1 warps less than 3mm on both sides, a mathematical model is established, the compensation angle is calculated using arctan, and the angle of the clamping jaw of the next electroplating is adjusted.

[0021] Specifically, in the embodiment, the angle of the clamping jaw is adjusted to 40°~60°.

[0022] Specifically, in the embodiment, during the electroplating process of the substrate 1, the electroplating time is 30 min ~120min, pulse electroplating and direct current electroplating mode are used, the electroplating bath temperature is 20℃~30℃, the copper sulfate concentration in the electroplating bath is 140 g / L ~150g / L, the sulfuric acid concentration is 160 g / L ~180g / L, and the chloride ion concentration is 10ppm~30ppm, so that copper crystal lattice is limited to grow on specific crystal surface, and directional dislocation is generated. Dislocation guide makes the substrate 1 release stress in fixed direction, generates controllable micro deformation, and further improves warping control precision Specifically, in the embodiment, the substrate 1 warping angle formula is: .

[0023] Specifically, in the embodiment, in the step "the front side circuit and the back side circuit of the substrate 1 are electroplated using different jet speed and current density;Wherein, high-speed jet and high current density are used for the front side circuit, and low-speed jet and low current density are used for the back side circuit", the speed of high-speed jet is 1.5m / s~2.0m / s, the high current density is 1.8A / dm2, the speed of low-speed jet is 0.5m / s~1.0m / s, and the low current density is 1.0A / dm2.

[0024] Specifically, in the present embodiment, in the step of "tempering the substrate after electroplating", the heating rate of the tempering process is 1℃ / min ~3℃ / min, and the cooling rate of the tempering process is 1℃ / min ~3℃ / min.

[0025] By the above method in the present embodiment, the warpage of the substrate 1 is effectively suppressed by adjusting the pre-stress introduced by the clamping jaw during electroplating, the plating uniformity is improved by using different jet speeds and current densities for the front side circuit and the back side circuit, the structural stability is improved by reducing the residual stress through tempering, the warpage precision is further improved by guiding the lattice misarrangement, and the warpage control has predictability and high precision by using a mathematical model for auxiliary design.

[0026] Embodiment 1 Substrate 1 preparation: select an IC carrier substrate 1 with a size of 100mm*100mm*0.5mm.

[0027] Clamping before electroplating: place the substrate 1 on the electroplating fixture, adjust the angle of the clamping jaw (2) to 50°, so that the substrate 1 is stretched in one direction.

[0028] Differential electroplating: front side circuit: use high-speed jet (1.8m / s) of electroplating liquid to spray from the nozzle, current density is 2.2A / dm 2 ; back side circuit: use low-speed jet (0.8m / s) of electroplating liquid to spray from the nozzle (3), current density is 1.2A / dm 2 .

[0029] Tempering: temper the electroplated substrate 1 in a nitrogen atmosphere at 200℃ for 1 hour. The heating rate of the tempering process is 1℃ / min ~3℃ / min, and the cooling rate of the tempering process is 1℃ / min ~3℃ / min.

[0030] Warpage measurement and compensation: measure the warpage of the electroplated substrate 1, if the warpage is less than 3mm, calculate the compensation angle using arctan according to the substrate 1 bending angle formula, and adjust the clamping jaw angle for the next electroplating.

[0031] The above disclosed content is only the preferred feasible embodiment of the present application, and does not limit the application patent range of the present application, so any equivalent technical changes made by applying the content of the present application specification and drawings are included in the application patent range of the present application.

[0032] Each embodiment in the specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other, and each embodiment mainly explains the difference from other embodiments.

[0033] While the application has been depicted, described, and is defined by reference to particular embodiments, those skilled in the art understand that modifications and variations can be made to the application without departing from the spirit or scope of the application, and it is therefore contemplated to include such modifications and variations as come within the scope of the application.

Claims

1. A method for processing a carrier plate to improve board warping, characterized in that, Includes the following steps: An IC substrate is provided, the substrate including front circuitry and back circuitry, the front circuitry being high-density circuitry and the back circuitry being a large copper surface; The substrate is electroplated, and the substrate is clamped using an electroplating clamping fixture. The fixture is equipped with jaws for clamping the substrate. The angle of the jaws is adjusted so that the substrate is stretched in one direction. Electroplating is performed on the front and back lines of the substrate using differentiated jetting speeds and current densities; wherein, high-speed jetting and high current density are used for the front lines, and low-speed jetting and low current density are used for the back lines. After the substrate is electroplated, it is subjected to tempering treatment; If the warping on both sides of the substrate is less than 3mm, a mathematical model is established, the compensation angle is calculated using arctan, and the clamp angle for the next electroplating is adjusted.

2. The carrier plate processing method for improving board warping according to claim 1, characterized in that, Adjust the angle of the gripper to 40°~60°.

3. The method for processing a carrier plate to improve board warping according to claim 1, characterized in that, During the electroplating process on the substrate, the electroplating time is 30 min to 120 min, pulse electroplating and DC electroplating are used, the temperature of the electroplating bath is 20℃ to 30℃, the concentration of copper sulfate in the electroplating bath is 140 g / L to 150 g / L, the concentration of sulfuric acid is 160 g / L to 180 g / L, and the concentration of chloride ions is 10 ppm to 30 ppm.

4. The method for processing a carrier plate to improve board warping according to claim 1, characterized in that, The formula for the substrate warping angle is: .

5. The method for processing a carrier plate to improve board warping according to claim 1, characterized in that, In the step "electroplating the front and back lines of the substrate using differentiated jetting velocities and current densities; wherein high-speed jetting and high current density are used for the front lines, and low-speed jetting and low current density are used for the back lines", the high-speed jetting velocity is 1.5 m / s to 2.0 m / s, and the high current density is 1.8 A / dm³. 2 The velocity of the low-speed jet is 0.5 m / s to 1.0 m / s, and the current density is 1.0 A / dm³. 2 .

6. The method for processing a carrier plate to improve board warping according to claim 1, characterized in that, In the step "tempering after electroplating the substrate", the heating rate of the tempering process is 1℃ / min ~ 3℃ / min, and the cooling rate of the tempering process is 1℃ / min ~ 3℃ / min.

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