| Point-of-care testing (POCT) chip is one kind of rapid testing chip in the clinical medicine, which develops from POCT technology and MEMS Systems. POCT chips can realize rapid and immediate testing, which has been applied in many aspects of detection, such as blood sugar, tumor, etc. For the high requirements of bonding precision, bonding strength, productivity and biological compatibility to POCT chip, the following research have done:1. Two kinds of joint structures are designed. And energy director layout is determined. Experimental chips are manufactured by MEMS system. The two kinds of joint structure are segregated joint structure and weld limited joint structure. Energy director, micro channel, weld pool and check welding platform are integrated in the joint structure. In the ultrasonic bonding, the bonding precision can be achieved through the check welding effect of the check welding platform. The structured energy director layout for POCT chips is determined, which contains liquid storage region, mixture region, delay-time region, detectable region and waste liquor region. Then the experimental chips are manufactured using hot embossing by silicon mold, which is manufactured by dry etching.2. The leveling jig is designed based on flexible leveling technology. And a method that is used to protect against scratches during ultrasonic bonding is proposed. The jig contains the main body, elastomer and base. The main body is designed to clamp the POCT chips. The elastomer, made from silicone rubber, is designed to realize the leveling function. The base is designed to be fixed with the bonding machine. In order to achieve the better leveling effect for POCT chips during ultrasonic bonding, the grouped leveling method is proposed. The structure parameter of every group is determined. And relevant testing experiment is carried out. The results demonstrate that the flexible leveling jig can increase the uniformity of pressure for bonding interface and simplify leveling operation significantly. In order to avoid the scratch by particulate between the horn and the bonding interface, the method of interstitial film is proposed. And relevant testing experiment is carried out. The results demonstrate that this method can decrease the scratch in the bonding interface.3. The joint structure and ultrasonic bonding process parameters are determined. The collapse-weld properties of the segregated joint structure and the weld limited joint structure are researched. The experimental results reveal that the segregated joint structure is easy to form bubbles during flow of the microfluid, which have bad influence on the detective function of POCT chips. So the paper chose the weld limited joint structure as the POCT chip's joint structure. The preliminary process parameters are determined by using the bonded micro channel's height as the first measure index. And then the experiment of bonding strength, airtightness test, liquid leakage test and whole blood driving are carried out based on the preliminary process parameter table. The results demonstrate that the structured energy director is rational, reliable and easy to integrate each function. The height of micro channel can be accurately controlled by the weld limited joint structure during ultrasonic bonding. The bonding precision of the micro channel is 2 ?m and the time range of whole blood driving test is less than 20 s. And the preliminary processing parameters can realize high bonding strength more than 2.5 MPa. And the energy director is welded uniformly. The chip's airtightness is fine which can work under 7 atmospheric pressures. |
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